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.
The Ministry of Science Technology and Innovation (MOSTI) Angkasawan (Astronaut) Programme achieved its mission to send the first Malaysian astronaut Sheikh Muszaphar Shukur by Soyuz TM11 to the International Space Ship (ISS) on 10 October 2007. He returned to earth, landing safely on 21 October 2007. Such a momentous event has carved out yet another milestone in the country’s
history and development of a civilisation based on science and technology for its people. This mission has provided the educational sector with an opportunity to initiate a curriculum innovation. Together with the Ministry of Education (MOE), the initiative was undertaken to improve techniques of teaching and learning (TL) and to broaden its scope to include space science and technology.
Malaysia is currently poised to introduce its Science, Technology and Innovation (STI) Policy and Act to bolster the nation's efforts at economic and social transformation. In championing this initiative, the Academy of Sciences Malaysia, while continuing to advise the Government on STI issues of the day, has made major strides in taking stock of the country's STI strengths in the various sectors of the economy as well as weaknesses that need to be addressed in terms of human capital development. In this article, the author examines the level of research expertise presently in the country in the field of chemistry, and elaborates on the four key areas of energy, catalysis and chemical synthesis, materials science and biological chemistry which will be researched globally in the next few decades that we would also need to be engaged upon to remain competitive. Intended for a wider audience than chemists alone, the descriptive sections in the article by and large belie an interdisciplinary flavour. The article also advocates the need for a more thorough road mapping exercise of the STI efforts in chemistry across the spectrum of academia and industry and makes some recommendations towards forging strong collaborations in research between the universities, public research institutes and the industry which are seen as vital in providing cross-cutting chemical solutions throughout the value chains and to the success of technologies identified as critical to the nation.
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.
A 2.4 GHz variable-gain low noise amplifier (VGLNA) intended for use in a Wide-band Code Division
Multiple Access receiver was designed in 0.18 um CMOS process for low voltage and low power applications. Rivaling classical designs using voltage mode approach, this design used the current mode approach, utilizing the current mirror principle to obtain a controllable gain range from 8.26 dB to 16.95 dB with good input and output return losses. By varying the current through the widths of transistors and a bias resistor, the VGLNA was capable of exhibiting 8 dB gain tuning range without degrading the noise figure. Therefore, higher gain was possible at lower current and thus at lower power consumption. Total power consumption simulated was 4.63 mW from a 1 V supply and this gave a gain/power quotient of 3.66 dB/mW. Comparing this with available published data, it was observed that this work demonstrated a good gain tuning range and the lowest noise figure with such power consumption.
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.
All relevant and essential data of an existing vehicle seat assembly line such as the operating time and processes, material handling system, workstation layout, bill of materials, equipment and hand tools, were collected and analyzed. The time standards for each of the vehicle seat assembly elements were established using work study techniques. A simulation approach was used to determine the productivity and effi ciency of the existing and proposed lines. Simulation technique was also used to determine and identify bottle-necks in both existing and proposed systems. Comparison of the existing assembly line and the proposed assembly line in terms of their productivity and effi ciency are also highlighted.
Surfactants are important class of material used in latexes to impart stability at the
solid/liquid interface. Ionic surfactants and nonionic surfactants are known to provide electrostatic
and steric stabilisation. In this study, two surfactants having chain length of twelve
hydrocarbons were added to the natural rubber latex (NRL) respectively to determine its zeta
potential values, adsorption isotherm and rheological properties. Previous study has shown
that optimum stability was observed when the alkyl chain of surfactant contains twelve carbon
atoms. The zeta potential magnitude of NRL in the presence of sodium dodecyl sulphate
increased as the surfactant concentration increases, while polyoxyethylene dodecyl ether did
not show a significant change in zeta potential. The isotherms were of Langmuir Type 1, the
amount of surfactant adsorbed per unit area at the plateau region was 6.0 × 10−6 mol m−2
for sodium dodecyl sulphate and 2.1 × 10−6 mol m−2
for polyoxyethylene dodecyl ether.
The elastic modulus and relative viscosity of the NRL suspensions increased significantly
in the presence of sodium dodecyl sulphate and also with polyoxyethylene dodecyl ether as
compared to the NRL system due to stronger colloidal forces. The maximum packing volume
fractions of the NRL stabilised with sodium dodecyl sulphate and polyoxyethylene dodecyl
ether were found to be lower than NRL itself.
In December 2009, at the UN Climate Change Conference COP 15 in Copenhagen, the Prime Minister of Malaysia, the Rt. Hon. Mohd Najib Abdul Razak, had announced that “Malaysia is adopting an indicator of a voluntary reduction of up to 40% in terms of emissions intensity of GDP by the year 2020 compared to 2005 levels. This indicator is conditional on receiving the transfer of technology and finance of adequate and effective levels from Annex 1 partners, that correspond to what is required in order to achieve this indicator”. Malaysia also needs to decouple its GDP from its current relatively high carbon-based energy demand. In trying to meet both these targets, we need to intensify our research efforts in energy-based areas. As government funding in R&D is limited as the aim is for research to be private-sector driven, and with the grim global economic scenario today, it is most unlikely that Malaysia will get any assistance financially or technologically from Annex 1 nations. It is therefore proposed that Malaysia considers implementing a dedicated carbon cess on petroleum products to fund R&D in the country. (Copied from article).
Cassava starch was used as feedstock for production of bioethanol by Saccharomyces cerevisiae. The cassava starch was hydrolyzed using commercial α-amylase and glucoamylase enzymes followed by a batch ethanol fermentation process using saccharified starch slurry. By using 110 g/L of reducing sugar from saccharified starch slurry, the ethanol yield was promising with maximum ethanol concentration of 20.6 g/L recorded after 55 hours of cultivation process. Three different models - the Logistic model, Luedeking-Piret-like equation and Gompertz equation - were used to characterize and explain the cell growth, reducing sugar consumption and production formation, respectively. The kinetic parameters were estimated by fitting the experimental data to the proposed models using non-linear regression analysis. The correlation coefficient r2 values for the Logistic model, Luedeking-Piret-like equation and the Gompertz equation were 0.994, 0.996 and 0.990, respectively. The high correlation coefficient values indicate that the proposed models were able to describe the ethanol fermentation process.
Fractional factorial design was utilized to evaluate the effect of combinations of nitric acid, hydrogen peroxide, hydrochloric acid and water for microwave digestion of fish muscle. Upon digestion, copper, iron and zinc were determined by flame atomic absorption spectroscopy. H2O2 and HCl volumes were found to be the most significant parameters which resulted in good metal recoveries. This is especially so for the effect of HCl on Fe recovery. The results indicated that the combination of 4 mL 65% HNO3, 2 mL 30% H2O2 and 2 mL 30% HCl gave the most satisfactory percentage recovery. There was good agreement between measured and certified values for all metals with respect to the DORM-3 fish protein.
Solvent flow reactor system was introduced into the extraction system to increase the system efficiency and enhance the extraction yield by adding fresh solvent during the extraction processes. The liquefaction experiment was carried out at various flow-rates (1, 3 and 5 ml/min), reaction times (30, 45 and 60 min) and reaction temperatures (300ºC, 350ºC, 400ºC, 420ºC and 450ºC) with tetralin as solvent. Despite the ability of adding fresh solvent into the extraction process, the conversion of oil+gas was still considered to be low as there was ~25% of coal extracts left to be converted into low molecular weight compounds. One possible option to increase the oil yield is by applying catalyst that will further break up the coal extracts into small molecular weight compounds. In this study, a second reactor was introduced consisting of catalyst (NiSiO2) assuming that the catalyst would interact more effectively with coal extracts rather than the coal itself. In the
absence of catalyst, the oil yield was 55%. By introducing the Ni catalyst, the oil yield increased by 15%. Further analysis of GCMS showed that the oil from catalytic liquefaction gave out more low molecular weight compounds in comparison to the un-catalytic liquefaction oil.
This article uses finite volume and finite element methods for optimization of the artificial hair cell sensor. The performance of the sensor was investigated for different materials such as sicon and polysilicon and by varying hair cell dimensions including width and length. The silicon material which has low young modulus was proposed based on the simulation performance. The performance of the hair cell sensor was achieved by increasing the hair cell length while increasing the width did not significantly influence the performance. The
performance of the sensor was studied for its viscous force, deflection, von mises stress and sensitivity. From the simulation, the hair cell with a length of 1600 µm and 80 µm width was suggested for the subsequent analysis. Another way to improve the performance was by modifying the hair cell geometry and it was proved that the modified hair cell was more sensitive, based on the deflection. The angle of flow that hit the hair cell also affected the deflection of the sensor where the zero angle flow which was parallel to the substrate was the most effective angle. The limitations of the performance of hair cell for various fluid velocity were also discussed in this paper.
Throughout the years, the construction industry has made an important contribution to the Malaysian economy. Moreover, the Ninth Malaysia Plan (2006–2010) has also played a significant role in the demands of executing major residential housing project developments where it has been observed that construction waste was one of the priority waste streams. Due to the increasing number in the population that is actively involved in economic activities, and the modernization of the country, the types of construction waste that are being produced, and identifying the source such as waste are becoming more complex. Therefore, appropriate actions and approaches are needed to be taken with respect to its effective management in handling the solid waste from construction sites. This paper is intended to review the issues and the challenges enclosed within the supply chain management mechanisms in order for improving construction waste management. Throughout this review, useful information and better understanding concerning the current issues, challenges and the supply chain management mechanisms would be made inclusive in the field to be explored. The findings would also assist in improving the quality and awareness on the construction waste management that is being practiced.
A four-stage erbium-doped fibre amplifier with the gain bandwidth of 35 nm is demonstrated. The amplifier was designed to include a dispersion compensating module to compensate the accumulated dispersion by signals. The amplifier design permited some dynamic features such as the amplifier’s gain could be adjusted from 15 dB to 30 dB by varying the input signal power from –26 dBm to 8 dBm. The maximum output power of 23 dBm was obtained with a maximum allowable gain flatness of 1.5 dB.
In this paper a study on the wideband double-pass Raman fibre amplifier with mirror as the pump reflector is reported. The pump lights at 1435 nm and 1455 nm were launched in a co-directional manner with respect to the input signal. The double-pass direction of the signal was achieved through a fibre loop mirror constructed using an optical circulator. It was shown that multiple signal amplification was achieved without any disturbance of stimulated Brillouin scattering.
The effects of topical application of Orthosiphon stamineus leaf extract on the rate of wound healing and histology of the healed wound were assessed. Four groups of adult male Sprague Dawley rats were experimentally wounded in the posterior neck area. A thin layer of blank placebo was applied topically to wounds of Group 1 rats. Wounds of experimental animals (Group 2 and 3) were dressed with placebo containing 5% and 10% O. stamineus extract, respectively. A thin layer of Intrasite gel® was applied topically to wounds of Group 4 animals as reference. Macroscopically, wounds dressed with placebo containing 5% (healed on day 14.50 ± 0.43) and 10% (healed on day 13.83 ± 0.21) O. stamineus extract each or Intrasite gel® (healed on day 13.13 ± 0.42) significantly accelerated the rate of wound healing compared to wounds dressed with blank placebo. Histological analysis of healed wounds confirmed the results. Wounds dressed with placebo containing 5%, 10% O.stamineus or Intrasite gel® showed markedly less scar width at wound enclosure and granulating tissue contained markedly more collagen, proliferating fibroblast with angiogenesis, and no inflammatory cells compared to wounds dressed with blank placebo. In conclusion, placebo containing 5% or 10% O. stamineus on extract-dressed wounds significantly accelerated the rate of wound healing in rats.
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
In this study, the implementation of the Regional Climate Model into the hydrodynamic model has been applied for streamflow projection on a river located at the south of Peninsular Malaysia within the years 2070 till 2099. The data has been obtained from a Regional Climate Model (RCM), named Précis, on a daily basis. It begins by comparing historical rainfall data generated from Précis versus the actual gauged recorded rainfall data from Department of Irrigation and Drainage Malaysia (DID). The bias of the generated rainfall data has been reduced by statistical techniques. The same has been applied to the future generated rainfall data from 2070 to 2099. Using the generated precipitation data as input to the hydrological model, results in the daily output of river discharge identified as the main contributor of flood occurrences. Based on the results of the hydrological model utilised, e.g. HEC-HMS, comparison was made between the future and historical generated discharge data using Précis between the years 1960 till 1998. Dividing a year into three segments, e.g. January-April, May-August, SeptemberDecember, the results show that there would be a significant drop of peak discharge in the third segment and an increase in discharge during the second segment. The first part remains almost with no changes. As an addition, the drop of the peak shows reduction in the probability of flood occurrences. It also indicates the reduction in water storage capacity which coherently affects the water supply scheme
As textile production flourishes nowadays, the amount of dyed wastewater entering the
water body has also increased. Dyes could have serious negative impacts to the environment
and also the human health, hence, they need to be removed from the water body. In this
study, layered double hydroxide (LDH) of manganese/aluminium (MnAl) was synthesised
to be used as a potential adsorbent to remove methyl orange (MO) dye due to its unique
lamellar structure which provides LDH with high anion adsorption and exchange ability.
MnAl was synthesized by using co-precipitation method and characterized by powder X-ray
diffraction (PXRD), Fourier-Transform Infrared Spectroscopy (FTIR), Inductively coupled
plasma atomic emission spectroscopy (ICP-AES) and Carbon, Hydrogen, Nitrogen, Sulphur
(CHNS) elemental analysers, and Accelerated Surface Area and Porosity Analyzer (ASAP).
Adsorption studies were conducted at different contact times and dosages of MnAl to evaluate
the performance of MnAl in removing MO from water. Kinetic and isotherm models were
tested using pseudo-first order, pseudo-second order, Langmuir isotherm and Freundlich
isotherm. MnAl LDH was found to be perfectly fitted into pseudo-second order and Langmuir
isotherm.