Sawdust: A green and economical sorbent for thallium removal

Removal/preconcentration of thallium(I) ions from aqueous solution by sawdust; a waste material derived from the commercial processing of Cedrus Deodar wood for furniture production was investigated. A simple and low-cost modification results in increasing the sorption capacity of raw sawdust from 2.71 to 13.18 mg g⁻¹. Sorption was found to be rapid (98% within 8 min). The binding of metal ions was found to be pH dependent, optimal sorption accruing at around pH 6–9. Potentiometeric titrations of sawdust revealed two distinct pK_a values, the first having the value similar to carboxylic groups (3.3–4.8) and second comparable with that of amines (8.53–10.2) with the surface site densities of 1.99 × 10⁻⁴ and 7.94 × 10⁻⁵ mol g⁻¹, respectively. Retained Tl(I) ions were eluted with 5 ml 0.1 mol l⁻¹ HCl. Detection limit of 0.0125 μg ml⁻¹ was achieved with an enrichment factor of 160. Recovery was quantitative using sample volume of 800 ml. The Langmuir, Freundlich and D–R isotherm equations were used to describe partitioning behavior for the system at different temperatures. Kinetic and thermodynamic behavior of sawdust for Tl(I) ions removal was also studied.     

Prevalence and Distribution of Arcobacter spp. in Raw Milk and Retail Raw Beef

A total of 106 beef samples which consisted of local (n = 59) and imported (n = 47) beef and 180 milk samples from cows (n = 86) and goats (n = 94) were collected from Selangor, Malaysia. Overall, 30.2% (32 of 106) of beef samples were found positive for Arcobacter species. Imported beef was significantly more contaminated (46.80%) than local beef (16.9%). Arcobacter butzleri was the species isolated most frequently from imported (81.8%) and local (60%) beef, followed by Arcobacter cryaerophilus in local (33.3%) and imported (18.2%) beef samples. Only one local beef sample (10%) yielded Arcobacter skirrowii. Arcobacter species were detected from cow's milk (5.8%), with A. butzleri as the dominant species (60%), followed by A. cryaerophilus (40%), whereas none of the goat's milk samples were found positive for Arcobacter. This is the first report of the detection of Arcobacter in milk and beef in Malaysia.     

Carbon nanofiber based buckypaper used as a thermal interface material

Carbon nanofiber (CNF) based buckypaper was explored as a potential thermal interface material (TIM) for electronics. CNFs were subjected to heat treatment temperatures of 1100 °C, 1500 °C and 3000 °C. TIMs were prepared and characterized using thermal impedance test stand. Results show that the thermal impedance at the interface decreased in conjunction with the increasing heat-treatment temperature of CNFs. TIMs with graphitized CNF exhibit a significant decrease of 54% in thermal impedance in comparison with the dry contact. This improvement is likely due to the high degree of CNF graphitizibility and the resulting outstanding electrical and thermal conductivities.     

POWER-Area-Performance Characteristics of FPGA-based Sigma-Delta FIR Filters

While one-bit ΣΔ modulators are widely used in Analog to Digital conversion stages due to their inherent linearity and precision, it is less common for the entire digital processing path to operate in single bit mode at the oversampled rate of the conversion system. The conventional approach has been to decimate the signal bit stream after conversion and for the remaining processing to be performed in standard multi-bit binary at the Nyquist rate and with a resolution mandated by the dynamic range and noise. Using a Finite Impulse Response filter design as an example, we compare the area and performance of this conventional approach with the alternative single bit approach that operates directly on the ΣΔ data stream using ternary coefficients {?1, 0, +1} derived from the ΣΔ modulation of the target impulse response. Filters exhibiting approximately equivalent spectral performance in the two alternative approaches were developed using VHDL and simulated using some commercial FPGA types. In these experiments, the single-bit filters using ternary coefficients were found to dissipate less power compared to the conventional approach despite their need to operate at much higher clock rates. They also exhibit up to 40% higher performance and offer useful area savings at lower filter orders. At higher orders, the ΣΔ approach retains its power and performance advantages but exhibits slightly higher chip area. The simplicity and low power of the ΣΔ approach makes it applicable to mobile communication processing using low cost FPGA technology.     

Context-based lossless interband compression-extending CALIC

This paper proposes an interband version of CALIC (context-based, adaptive, lossless image codec) which represents one of the best performing, practical and general purpose lossless image coding techniques known today. Interband coding techniques are needed for effective compression of multispectral images like color images and remotely sensed images. It is demonstrated that CALIC's techniques of context modeling of DPCM errors lend themselves easily to modeling of higher-order interband correlations that cannot be exploited by simple interband linear predictors alone. The proposed interband CALIC exploits both interband and intraband statistical redundancies, and obtains significant compression gains over its intrahand counterpart. On some types of multispectral images, interband CALIC can lead to a reduction in bit rate of more than 20% as compared to intraband CALIC. Interband CALIC only incurs a modest increase in computational cost as compared to intraband CALIC.     

An event‐flow model of GUI‐based applications for testing

Graphical user interfaces (GUIs) are by far the most popular means used to interact with today's software. The functional correctness of a GUI is required to ensure the safety, robustness and usability of an entire software system. GUI testing techniques used in practice are resource intensive; model‐based automated techniques are rarely employed. A key reason for the reluctance in the adoption of model‐based solutions proposed by researchers is their limited applicability; moreover, the models are expensive to create. Over the past few years, the present author has been developing different models for various aspects of GUI testing. This paper consolidates all of the models into one scalable event‐flow model and outlines algorithms to semi‐automatically reverse‐engineer the model from an implementation. Earlier work on model‐based test‐case generation, test‐oracle creation, coverage evaluation, and regression testing is recast in terms of this model by defining event‐space exploration strategies (ESESs) and creating an end‐to‐end GUI testing process. Three such ESESs are described: for checking the event‐flow model, test‐case generation, and test‐oracle creation. Two demonstrational scenarios show the application of the model and the three ESESs for experimentation and application in GUI testing. Copyright © 2007 John Wiley & Sons, Ltd.     

Sawdust--a green and economical sorbent for the removal of cadmium (II) ions

The ability of sawdust (treated and untreated) waste, a waste material derived from the commercial processing of cedrus deodar wood for furniture production, to remove/preconcentrate Cd(II) ions from aqueous solution was determined. Sorption was found to be rapid (approximately 97% within 8 min). The binding of metal ions was found to be pH dependent, optimal sorption accruing at around pH 4-8. Potentiometric titrations of sawdust revealed two distinct pK(a) values, the first having the value similar to carboxylic groups (3.3-4.8) and second comparable with that of amines (8.53-10.2) with the densities 1.99 x 10(-4) and 7.94 x 10(-5), respectively. Retained Cd(II) ions were eluted with 5 ml of 0.1 mol l(-1) HCl. Detection limit of 0.016 microg ml(-1) was achieved with enrichment factors of 120. Recovery was quantitative using sample volume of 600 ml. The Langmuir and D-R isotherm equations were used to describe partitioning behavior for the system at different temperatures. Kinetic and thermodynamic behavior of sawdust for Cd(II) ions removal was also studied.     

A review on fuel economy standard for motor vehicles with the implementation possibilities in Malaysia

This paper focused on a review of international experiences on fuel economy standard based on technologies available. It also attempts to identify savings possibilities and greenhouse gas (GHG) emissions reductions. It is known that road transport, particularly private cars are responsible for large, and increasing share of transport fuel use and emissions. With the implementation of fuel economy standard and label for motor vehicles, it will reduce the risks of increasing dependency on petroleum-based fuel and will increase the profit to consumers. The GHG emissions, which causing global warming, air pollution, diseases, etc. can be reduced as well. In this regard, advanced technologies such as, engine, transmission, and vehicle technologies may brought significant consumers and social benefits. Studies in developed countries have shown that fuel economy standard is beneficial for the society, government as well as the environment.     

Recent advances and developments in advanced green porous nanomaterial for sustainable energy storage application

Journal of Porous Materials - Compared with traditional battery and super capacitor materials, nanomaterials can significantly improve ion transport and electron conductivity. There are many...