A preliminary study was carried out to fabricate a three electrode system based on electrochemical sensoring. The cyclic voltammetry (CV) technique was chosen to select the type of metal suitable for evaporation and to compare the results produced from the fabricated gold electrode with the conventional macro-electrode system. The methodology and apparatus used involved low cost apparatus and methodology such as soft lithography, wet-etching, thermal evaporation, direct current sputtering, polymethylmethacrylate moulding and polydimethylsiloxane coating. The experiment was conducted at a fixed scan rate of 100 mV/s by using 0.01 M K3Fe(CN)6 in 0.1M KCl and well known method using Randles-Sevcik equation, peak current ratio and voltage separation was used to analyze the characterization on the fabricated sensors. Electrodes of 6.5 mm2 and 0.26 mm2 were fabricated to prove the adsorption effect of the reactant and the influence of the electrode area on the value of the peak current. CV analysis proved that the fabricated sensor was reliable for a range of 24 h at 25ºC room temperature.
Two sequential statistical experimental designs were used to screen and investigate the dependence of the amount of biodegradation of Procion Red MX-8B (PR-MX8B) on the fermentation variables. Fourteen factors were screened using the Plackett-Burman design. Among these factors, the most significant variables which included yeast extract, corn steep solids and starch influencing PR-MX8B decolourisation were statistically elucidated for optimization. The optimum concentrations of 5.00 g/l yeast extract, 2.99 g/l starch and 1.89 g/l corn steep solids were predicted by applying the Box-Behnken design to the second order polynomial model fitted to the results obtained. The best predicted optimal conditions verified experimentally yielded 72.11% while the predicted value from the polynomial model was 79.17%. The experimental values were in good agreement with the predicted values with a 90.81% degree of accuracy.
In this paper, an improved method of reducing ambient noise in speech signals is introduced. The proposed noise canceller was developed using a computationally efficient (DFT) filter bank to decompose input signals into sub-bands. The filter bank was based on a prototype filter optimized for minimum output distortion. A variable step-size version of the (LMS) filter was used to reduce the noise in individual branches. The subband noise canceller was aimed to overcome problems associated with the use of the conventional least mean square (LMS) adaptive algorithm in noise cancellation setups. Mean square error convergence was used as a measure of performance under white and ambient interferences. Compared to conventional as well as recently developed techniques, fast initial convergence and better noise cancellation performances were obtained under actual speech and ambient noise.
The genus Streptomonospora is a group of extremely halophilic filamentous actinomycetes that form a distinct branch in the 16S rRNA gene phylogenetic tree adjacent to the genera Nocardiopsis and Thermobifida, family Norcadiopsaceae. To date, genus Streptomonospora only contain two validly described species which are Streptomonospora salina and Streptomonospora alba. During a biodiversity study on halophilic filamentous actinomycetes from 18 co-ordinates in Barrientos Island, Antarctic, numerous actinomycetes strains were isolated. To identify whether these isolates were members of the genus Streptomonospora, a genus specific primer that allow the rapid detection of the genus Streptomonospora by means of PCR amplification was used. Furthermore molecular cloning was performed to make identical and multiple copies of the target gene. In addition, morphological characteristic identification was performed to validate isolates with positive amplification during PCR.
Chlorella is one of the common microalgae found in a wide range of habitats, including Antarctica. Chlorella UMACC 234 is an interesting isolate in the collection of Antarctic microalgae in the University of Malaya algae culture collection (UMACC) as it grows well at temperatures much higher than the ambience. The alga was isolated from snow samples collected from Casey, Antarctica. This study investigates the influence of nitrogen source on the growth, biochemical composition and fatty acid profile of Chlorella UMACC 234. The cultures were grown in Bold’s Basal Medium with 3.0 mM NaNO3, NH4Cl or urea. The cultures grown on NaNO3 attained the highest specific growth rate (μ = 0.43 day–1) while the specific growth rates of those grown on NH4Cl and urea were not significantly different (p > 0.05). The urea-grown cells produced the highest amounts of lipids (25.7% dry weight) and proteins (52.5% dry weight) compared to those grown on other nitrogen sources. The cell numbers attained by the cultures grown at NaNO3 levels between 0.3 and 3.0 mM were similar but decreased markedly at 9.0 mM NaNO3. The fatty acids of Chlorella UMACC 234 were dominated by saturated fatty acids, especially 16:0 and 18:0. The percentage of polyunsaturated fatty acids was very low, especially in cells grown on urea (0.9% total fatty acids). Characterisation of the growth and biochemical composition of this Antarctic Chlorella is important to our studies on the relationship of Chorella isolates from tropical, temperate and polar regions, especially in terms of phylogeny and stress adaptation.
The receptor-interacting protein 140 (RIP 140) is a well known nuclear repressor and has been shown to be crucial for female reproduction and metabolism. However, the function of this repressor in developmental processes is still unknown. We conducted a study to investigate the expression patterns of RIP 140 in developing zebrafish embryos. Semi-quantitative RT-PCR analysis revealed that RIP140 was highly expressed in the eye, swim bladder, reproductive and metabolic organs of adult zebrafish. During embryogenesis, RIP 140 mRNA was continuously expressed throughout all the developmental stages with the highest expression at 24 hours of post-fertilization (hpf). Furthermore, in situ hybridization whole-mounts revealed that the expression of this gene was mainly localized in the eyes, mid-brain, pectoral fin buds and somites. Therefore, this present study has provided a starting point for future investigations to examine the role of RIP 140 in the development of these organs.
In this multiple-subject study, intrinsic couplings between the primary motor (M1) and supplementary motor areas (SMA) were investigated. Unilateral (UNIright and UNIleft) self-paced tapping of hand fingers were performed to activate M1 and SMA. The intrinsic couplings were analysed using statistical parametric mapping, dynamic causal modeling (DCM) and Bayesian model analysis. Brain activation observed for UNIright and UNIleft showed contralateral and ipsilateral involvement of M1 and SMA. Ten full connectivity models were constructed with right and left M1 and SMA as processing centres. DCM indicated that all subjects prefer M1 as the intrinsic input for UNIright and UNIleft as indicated by a large group Bayes factor (GBF). Positive evidence ratio (PER) that showed strong evidence of Model 3 and Model 6 against other models in at least 12 out of 16 subjects, supported GBF results. The GBF and PER results were later found to be consistent with that of BMS for group studies with high expected posterior probability and exceedance probability. It was concluded that during unilateral finger tapping, the contralateral M1 would act as the input centre which in turn triggered the propagation of signals to SMA in the same hemisphere and to M1 and SMA in the opposite hemisphere.
Surface coverage and some properties soil chemicals were assessed at the Punta Fort William, Greenwich Island during the summer from 1–11 February 2008. Twenty sampling points were established along two strip transects covering a total area of 160 m2. Punta Fort William was basically barren. Rocks, stones and pebbles covered 89.4% of the Punta Fort William. The diversity of vegetation in Punta Fort William was relatively low as compared to other South Shetland Islands. Mosses predominated the area and covered 9.1% of the total surface. Colobantus quitensis was the only vascular plant found at the Punta Fort William. It covered 0.5% of the total surface area. Lichens contributed 0.2% of the surface coverage. Although lichen coverage was low, its frequency of occurrence was among the highest. Total organic carbon (TOC) and total nitrogen (TN) in the study area ranged from 1 g to 39 g C kg–1 and 12 μg to 3892 μg N kg–1, respectively. The level of TOC and TN were comparable to those reported in other maritime locations in Antarctic. Higher levels of TOC and TN were detected in the areas with intensive biological activities. Hydrocarbon concentration was very low in this area and the sources of hydrocarbons were both natural and anthropogenic. The natural hydrocarbons source was mostly biogenic while the petrogenic hydrocarbons input was anthropogenic.
Three techniques to retrieve information on sea ice thickness from both active and passive radar backscatter data are presented. The first inversion model is a combination of the radiative transfer theory with dense medium phase and amplitude correction theory (DMPACT), and the Levenberg-Marquardt optimization algorithm. The radiative transfer theory was applied as the forward model to generate radar backscatter data, while the DMPACT was included to account for the close spacing effect among the scatterers within the medium. The Levenberg-Marquardt optimization algorithm was then applied to reduce the error between the model generated radar backscatter data and the measured radar backscatter data from satellite images so that the sea ice thickness could be estimated. The second method presented was the neural network inversion method which utilizes a chain of neurons with variable weights. Once the network was fully operational it would be possible to predict the sea ice thickness, provided sufficient training data are given. The last method was the genetic algorithm which is a search technique used in order to predict the approximate sea ice thickness from the measured data. Data from ground truth measurements carried out in Ross Island, Antarctica, together with radar backscatter data extracted from purchased satellite images were used as input to verify the models. All three models were tested and successfully predicted sea ice thickness from actual terrain using the ground truth measurement data, with several constraints and assumptions placed to avoid problems during the retrieval process. While the models still have their own limitations, the potential use of the models for actual sea ice thickness retrieval was confirmed.
Frequency hopping spread spectrum (FHSS) systems with partial band interference require appropriate compounding of spread spectrum modulation, error correcting code, diversity and decoding method to receive improved transmission signal. In this paper, a fast FHSS system with regular low-density parity-check codes was employed to cater some anti-jamming competence by using good waterfall and error floor performance. The performance evalution of the previously mentioned system was conducted in the presence of partial band noise jamming. The best possible design of the system was achieved with the combination of diversity level L=2 with a probability rate of at 0.7 dB which showed the robustness of the system.
In this paper, the problem of steady laminar boundary layer flow of an incompressible viscous fluid over a moving thin needle is considered. The governing boundary layer equations were first transformed into non-dimensional forms. These non-dimensional equations were then transformed into similarity equations using the similarity variables, which were solved numerically using an implicit finite-difference scheme known as the Keller-box method. The solutions were obtained for a blunt-nosed needle. Numerical computations were carried out for various values of the dimensionless parameters of the problem which included the Prandtl number Pr and the parameter a representing the needle size. It was found that the heat transfer characteristics were significantly
influenced by these parameters. However, the Prandtl number had no effect on the flow characteristics due to the decoupled boundary layer equations.
In this project, a Geographic Information System (GIS) was used to collect and compile various field data in the Pedro Vicente Maldonado Ecuadorian Scientific Station Antarctica Base area. The main source of data was obtained from a global positioning system (GPS) survey using kinematic GPS (GPS-RTK) which allowed continuous point mapping in the terrain. GPS units were utilized in the collection of spatial data for all field work. The co-ordinates obtained were used to produce a point map which was then exported into GIS software where the proximity of cartographic phenomena and boundaries were mapped. All the collected data were subsequently gathered to develop the GIS database which was then used to generate and compile different maps to test for spatial and temporal relationships. The output of the project comprises a GIS database, spatial maps and 3D terrain model of the area. The developed GIS database can be used with other ecological datasets to provide biogeographical information, potential range distribution and sampling adequacy. The database is also applicable to geographical management and multi-disciplinary research projects.
In this study the effects of phosphorus and nitrogen levels, temperature and light-dark cycle on the algal growth potential (AGP) of an Antarctic Chlorococcum isolated from an ephemeral stream at Reeve Hill, Antarctica was investigated. The highest AGP was attained when the cultures were grown at high nitrogen concentration (329.87 mg NO3-N/l) and low phosphorus concentration (2.6 mg PO4-P/l) at 4ºC on a 12 h:12 h light-dark cycle. The results showed that Chlorococcum sp. required a high concentration of nitrogen, low concentration of phosphorus, low temperature with equal lengths of light and dark period (12 h:12 h) for optimum growth.
A study to determine the impact of leachate from operating and closed landfills into the surface water and groundwater systems in the state of Selangor was conducted in the year 2009. Groundwater was a major source of water for various uses in Selangor, Malaysia and was especially important for industrial purposes. The presence of high numbers of landfill sites was seen to have increased the risk of groundwater contamination. There were 20 landfill sites in the state of Selangor and seven of them were still operating and 13 closed. The landfills are classified into four categories, which were: (a) landfills operating at critical stages without controls to prevent pollution into the environment; (b) open dumpsites that have the capacity to continue to accept waste but needed to be upgraded to manage leachate and gas; (c) landfills that were closed but no safety closure plan was carried out; and (d) engineered landfills with up to date technologies. As most of the landfills were built prior to 1989, they were not subjected to the Environmental Impact Assessment requirements, hence, they were being poorly managed and were badly sited. The non-engineered sites had no proper pollution controls such as cover materials, liner materials, groundwater monitoring wells, leachate collection ponds and treatment, and methane gas collection pipes. This study revealed that the surface water and groundwater at and nearby the landfill sites were contaminated at various levels due to the landfill sites and operation. A comparison between the current quality of surface water and groundwater with their respective standards and background levels was carried out to survey the trend of the contamination. However, the limited financial resources hindered a very thorough investigation and restricted the number of samples collected and parameters analysed.
Lead-free solder paste printing processes account for the majority of assembly defects in the electronic manufacturing industry. In the stencil printing process, the solder paste must be able to withstand low and high shear rates which result in continuous structural breakdown and build-up. This study investigated the effect of the addition of nickel and platinum powders to the thixotropic behaviour of lead-free Sn/Ag/Cu solder pastes using the structural kinetic model. A hysteresis loop test and constant shear test were utilized to investigate the thixotropic behaviour of the pastes using parallel plate rheometry at 25ºC. In this study, the shear rates were increased from 0.01 s–1 to 10 s–1 and the second curve was a result of decreasing the shear rate from 10 s–1 to 0.01 s–1. For the constant shear test, the samples were subjected to five different shear rates of 0.01s–1, 0.1s–1, 1s–1, 10s–1 and 100s–1. The constant shear rate test was designed to study the structural breakdown and build-up of the paste materials. From this investigation, the hysteresis loop test was shown to be an effective test method to differentiate the extent of structural recovery in the solder pastes. All the pastes showed a high degree of shear thinning behaviour with time. This might be due to the agglomeration of particles in the flux that prohibited paste flow under low shear rate. The action of high shear rate would break the agglomerates into smaller pieces which facilitated the flow of pastes, thus viscosity was reduced at high shear rate.
Molecular dynamics reaction simulation showed that the rate constant is not constant over the concentration profile of reactants and products over a fixed temperature regime, and this variation is expressed in terms of the defined reactivity coefficients. The ratio of these coefficients for the forward and backward reactions were found to equal that of the activity coefficient ratio for the product and reactant species. A theory was developed to explain kinetics in general based on these observations. Several other theorems had first to be developed, most striking of all was the inference that the excess Helmholtz free energy was the thermodynamical function which had a direct relation to these activity factors than the Gibbs free energy. The theory is applied to a class of ionic reactions which could not be rationalized using the standard Bjørn-Bjerrum theory of ionic reactions.
Silicon, as the most important electronic material, has a lot of applications in the electronic industry and this includes the use of silicon in solar cells. One of the solar grade silicon production processes is the use of acid leaching for the removal of metallic impurities from silicon. The main advantage of this process for silicon purification is that it is based on a low temperature process. The purification of metallurgical grade silicon by acid leaching was studied as a function of time, temperature and etching. Based upon experimental results and under optimum conditions, it was possible to remove 41%, 71% and 25% of iron, calcium and aluminum respectively, with the use of aqua regia.
Ocimum basilicum seed extracts were found to possess significant anti-ulcer activity against ethanol-induced ulceration in experimental animal models. Three groups of adult male rats were used, with each group consisting of six rats. Oral administration of absolute ethanol to rats pre-treated with 10% Tween 20® (Group 1) produced extensive haemorrhagic lesions of the gastric mucosa. Rats orally pre-treated with O. basilicum extract suspended in 10% Tween 20® (Group 2) or cimetidine in 10% Tween 20® (Group 3), 30 min before oral administration of absolute alcohol had significantly reduced (p
The effects of anticipated climate change and the potential impact on animal production are discussed in the context of varying biophysical features, agro-ecological zones (AEZs), ecosystems, land use, and responses in animal genetic diversity and production. The AEZs in Asia have great diversity in their links to food production in crop-animal small farm systems, the poverty complex and livelihoods of the poor. In these environments. climate change effects on animals were mediated through heat stress, water availability, quantity and quality of the available feed resources, type of production system and productivity. The responses to heat stress are tabulated and they vary according to species, breeds within-species, AEZs, physiological and nutritional status, genetic potential and multifunctionality. Among ruminant production systems, dairy production was especially vulnerable to heat stress. Interestingly in India, buffalo numbers owned largely by the landless and small farmers in the semi-arid and arid regions have grown twice as fast as the buffalo population in the irrigated areas. The implications and strategies to cope with climate change involve mitigation, adaptation and policy. The principal strategy is targetting to the reduce on in greenhouse gas (GHG) emission from the agricultural sector from enteric fermentation and manure, and ways to intensify C sequestration. An important link is that of breeding and conserving indigenous animal genetic resources as a means to mitigate climate change, with associated benefits to the trade of live animals and animal products. Improved integrated tree crops-ruminant systems are an important pathway to enhance C sequestration. The opportunities for research and development (R&D) are enormous and they would need policy support and large investments to provide improved understanding of ways to ensure sustainable animal production systems. Coping with the totality of the effects and impact of climate change constitutes the challenges for agricultural R&D and the improved livelihood of the resource-poor in the future.
Malaysia has adopted various strategies in developing its space sector. Indigenous space technologies would enable a sustainable growth of the space field and at the same time develop the strategic space technologies. Therefore, issues related to the current space research level are fundamentally crucial to be highlighted. Subsequently, the space focus areas can be derived in order to meet the expectations of the national and international space technology growth requirements, which are moving on to a stronger posture in R&D. In the absence of a strong R&D national space industry leadership, the Malaysian space sector remains in a traditional downstream mode of the world space technology supply chain ever since. The space technology supply chain can be divided into the ground segment and the space segment. This paper examines the current space research activities in Malaysia within the framework of the space technology supply chain. As a result, a preliminary gap in the overview of space research in Malaysia is established.