The roots of Calophyllum inophyllum (Guttiferae), furnished six xanthones which are brasilixanthone (1), 1,3,5-trihydroxy-2- methoxy xanthone (2), caloxanthone A (3), pyranojacareubin (4), caloxanthone B (5) and tovopyrifolin (6), Structural elucidations of these compounds, were achieved through 1D and 2D NMR andMS techniques. In this paper, the isolation and structural elucidation data for these xanthones are reported.
This paper investigates several asymptotic confidence interval estimates, based on the Wald, likelihood ratio and the score statistics for the parameters of a parallel two-component system model, with dependent failure and a time varying covariate, when data is censored. This model is an extension of the bivariate exponential model. The procedures are investigated via a coverage probability study using the simulated data. The results clearly indicate that the interval estimates, based on the likelihood ratio method, work better than any of the other two methods when dealing with the censored data.
A field study was conducted on the effect of four primary tillage implements and three seed densities on the grain yield of rain fed wheat (Tajan cultivar), using a drill planting machine with the end wheels. The experimental design was a split plot design in a 4×3 factorial with three replications. In this study, the main plots were the tillage treatments, namely Mouldboard plough, Disc Plough, Chisel Plough, Offset Disc, and sub-plots were seed rates of 350, 400 and 450 seeds.m-2. Determinations included grain yield and selected yield components. The results showed that grain yield was not affected by the densities of seed and tillage machine treatments. The use of Chisel Plough, with 400 seeds.m-2 sowing rate, had the highest grain yield of wheat grown in the Golestan province (Iran), a region with an average annual rainfall of 450 mm.
Compartmented Fluidized Bed Gasifier (CFBG), consisting of two compartments - the combustorand gasifier, uses air blown instead of pure oxygen for syngas production in bubbling fluidization mode, eliminating the need of air separation unit, and reducing the capital cost, thus distinguishes it from other traditional ones. Fluidization quality is a determining factor in the CFBG to guarantee its well-lifted behaviour. Previous study, without solid circulation at ambient conditions, brought to the fore the necessity of considering the effect of the minimum allowable effective diameter. The study was then performed in the CFBG cold physical model of 0.66m overall diameter (effective diameter for combustor and gasifier is 0.413m and 0.257m) to investigate the fluidization quality and compare it with the results obtained from the previous cold model of about 1.36 times smaller, but with the same compartmented ratio of 65:35. Different inert particles (river sand, quartz sand and alumina) were used, over a range of aspect ratios, for the aforementioned objective. The results showed that the fluidization quality in the gasifier has not been achieved and the degradation of fluidization quality in the combustor is still observed, notwithstanding the fact that the condition of the minimum allowable effective diameter has been met. The reduction of distributor free area, to increase the distributor pressure drop, showed a marginal effect on the quality. The effect of the minimum allowable effective diameter on fluidization quality in CFBG as well as the interplay of geometric and operational parameters require further studies be carried out. The fluidization quality of the binary mixture is also currently under investigation.
The production of carbon dioxide from Karas woods under argon atmosphere was investigated using a direct pyrolysis-combustion approach. Direct burning was used in this study, using argon for yrolysis and oxygen during combustion to look at the yield of carbon dioxide, produced at different parameters, such as the temperature, retention time and flow rate of argon, as the carrier gas. In this study, a new methodology, 23 response surface central composite design was successfully employed for the experimental design and analysis of results. Central composite experimental design and response surface method were utilized to determine the best operating condition for a maximum carbon dioxide production. Appropriate predictable empirical linear model was developed by incorporating interaction effects of all the variables involved. The results of the analysis revealed that linear equation models fitted well with the experimental for carbon dioxide yield. Nevertheless, the R-Squared obtained using the direct pyrolysis-combustion was 0.7118, indicating that the regression line was not at the best-fitted line.
Thermodynamic chemical equilibrium analysis using, total Gibbs energy minimization method, was carried out for methane oxidation to higher hydrocarbons. For a large methane conversion and a high selectivity to higher hydrocarbons, the system temperature and oxygen concentration played a vital role, whereas, the system pressure only slightly influenced the two variables. Numerical results showed that the conversion of methane increased with the concentration of oxygen and reaction temperature, but it decreased with pressure. Nevertheless, the presence of oxygen suppressed the formation of higher hydrocarbons which mostly consisted of aromatics, but enhanced the formation of hydrogen. As the system pressure increased, the aromatics, olefins and hydrogen yields diminished, but the paraffin yield improved. Carbon monoxide seemed to be the major oxygen-containing equilibrium product from methane oxidation, whilst almost no H2O, CH3OH and HCOH were detected although traces amount of carbon dioxide were formed at relatively lower temperature and higher pressure. The total Gibbs energy minimization method is useful to theoretically analyze the feasibility of methane conversion to higher hydrocarbons and syngas at the selected temperature and pressure.
The adsorption of phenol, from aqueous solutions on activated carbon from waste tyres, was studied in a batch system at different initial concentrations (100-500mg/L) at 30°C for 48 hours. The activated carbon was prepared using the two-step physiochemical activation, with potassium hydroxide (KOH) at ratio KOH/char = 5. The carbonization process was done at 800°C for 1 hour with nitrogen flow rate 150ml/min, followed by the activation with the carbon dioxide flow rate 150ml/min at 800°C for 2 hours. The adsorption isotherms were determined by shaking 0.1g of activated carbon with 100ml phenol solutions. The initial and final concentrations of phenol in aqueous solution were analyzed using the UV-Visible Spectrophotometer (Shimadzu, UV-1601) at a wavelength of 270nm. Experimental isotherm data were analyzed using the Langmuir and Freundlich isotherm models.The equilibrium data for phenol adsorption could fit both isotherm models well with the R2 value of 0.9774 and 0.9895, respectively. The maximum adsorption capacity of the adsorbent obtained from the Langmuir model was up to 156.25 mg/g
In this study, an anaerobic mesophilic bacterial strain, namely Clostridium butyricum KBH1, was isolated from a natural source. This strain grew well and produced biogas with an average hydrogen concentration of 60% (v/v) in the Reinforced Clostridial Media (RCM). To study the basic nutrient requirements, three main nutrients namely peptone (Pep), yeast extracts (Yes) and glucose (Glu) were chosen as factors, using an experimental design. The experiments were run according to 23 Full Factorial Design, followed by the Response Surface Method (RSM). The fermentation was performed in 30 ml serum bottles with 20 ml working volume in a sterile and anaerobic condition at 37°C with 5% inoculums. The results from the Analysis of Variance (ANOVA) for the factorial design showed that all the three factors had significantly affected the gas production by the C. butyricum. The response surface plot of the gas production by C. butyricum showed that the gas production could be enhanced by increasing peptone and yeast extract concentrations up to 15 g/l and 24 g/l respectively, without showing any substrate inhibition. Meanwhile, the glucose concentration showed an optimum at the middle point (8 g/l) with possible substrate inhibition at a high concentration (12 g/l). The total biogas production could be correlated to the three factors, using the quadratic equation: Gas =0.17 + 7.11Glu - 0.02Pep + 0.77Yes - 0.53Glu2 + 0.09Glu*Pep. The experimental results showed that the strain could grow well in substrate with high organic nitrogen content such as POME and might be not suitable for substrate with high sugar content due to substrate inhibition.
The dielectrophoretic (DEP) separation of cell, using microelectrodes structure, has been limited to small scale due to size of the substrate. This work was carried out to extend the capability of microelectrodes system by orientating the microelectrodes in three dimensions (3-D) for larger scale dielectrophoretic separation of microorganism. The designed 3-D separation chamber consists of microelectrodes on two opposing walls. Based on the FEMLAB simulation, the electric field was seen to be generated across the chamber, rather than between adjacent electrodes in the same plane like in the small scale system. This configuration led to a stronger electric field in the bulk medium. The experimental results showed that the 3-D microelectrodes chamber behaved similar to the system with microelectrodes on one wall. The effects of the main parameters such as voltage, frequency and flow rates were similar to that of the systems with all the electrodes on one wall, but on the overall, capture more cells. A gap size between 250 – 500 μm resulted in an electric field which is strong enough to hold cells while giving a reasonable cross sectional area at the same time. Although there is some improvement achieved by 3-D system, it is still not very much, as compared to the small scale system.
The production of ethanol, from glucose in batch and fed batch culture, was investigated. In the fed batch culture, the glucose feeding was added into the culture at 16th hour of fermentation. The effects of different glucose concentration feeding rates on ethanol fermentation were investigated for fed batch culture. The 2gL-1hr-1 glucose concentration feeding rate was found to give higher ethanol yield (2.47 g ethanol g glucose-1), with respect to substrate consumed as compared to 8 gL-1hr-1 (0.23 g ethanol g glucose-1) and 4 gL-1hr-1 (0.20 g ethanol g glucose-1). The ethanol yield with respect to substrate consumed obtained in batch culture was 0.81 g ethanol g glucose-1. The fed batch culture at 2 gL-1hr-1 glucose concentration feeding rate was proven to be a better fermentation system than the batch culture. The specific growth rate, specific glucose consumption rate and specific ethanol production rate for the fed batch fermentation, at 2 gL-1hr-1 glucose concentration feeding rate, were 0.065 hr-1, 1.20 hr-1 and 0.0009 hr-1, respectively.
Synthesis of carboxymethylcellulose (CMC) from natural cellulose is an important industrial process. The effect of process parameters on the synthesis process is important information for the efficiency improvement of production process. Most of the previous studies on the effect of process parameters
on the synthesis of CMC are based on the One-Factor-At-Time (OFAT); therefore, in this work, the response surface methodology (RSM) was used. Here, the cellulose was converted to CMC through
carboxymethylation process using a technique of William etherification in heterogeneous system. The process parameters studied include the solvent ratio, reaction temperature and reactant ratio (molar ratio of NaOH to SMCA). Meanwhile, the analysis and optimization of the responses of the process, degree of substitution (DS) and yield were also performed using the response surface methodology. The validity of the synthesis process was identified by the determination of CMC spectrum using the fast Fourier infrared spectrometer (FTIR). The analysis of the results shows that carboxymethylation is strongly affected by combination of process parameters studied. The results obtained also show that the optimum responses, degree of substitution (DS) is 0.87 and yield is 1.80, whereas the optimum process parameters, solvent ratio is 0.70v/v, reaction temperature at 56.03oC, and molar ratio of NaOH to SMCA at 1.00mol/mol. These findings conclude that the DS and yield of carboxymethylation of cellulose are strongly affected by the combination of the process parameters.
An antimicrobial (AM) Active Packaging can be made by incorporating and immobilizing suitable AM agents into food package matrices and applying a bio switch concept. A starchbased film was prepared and incorporated with an antimicrobial agent, i.e. lysozyme with EDTA as a chelating agent. This film was then inoculated with the bacteria Escherichia coli and Bacillus subtilis to carry out the microbial contamination study. The inhibition of both E. coli and B. subtilis by the AM film was clearly observed as a clear zone formation in the culture agar test. The film appearance showed that lysozymes could give a better inhibition to the growth of E. coli and to B. subtilis, at a satisfying inhibition rate. From the broth test, the decreased in the optical densities were found to be 65.83% and 91.30%, suggesting an effective growth inhibition of E. coli and B. subtilis, respectively. Physically, the film which was incorporated with lysozymes was found to be slightly different from the control film. The moisture content of the film, with lysozymes, was found to be below 10.5%, as compared to the control, after 24 hours of formation in the storage at ambient temperature.
Nowadays, Concurrent Engineering (CE) is becoming more important as companies compete in the worldwide market. Reduced time in product development process, higher product quality, lower cost in manufacturing process and fulfilment of customers’ requirements are the key factors to determine the success of a company. To produce excellent products, the concept of Concurrent Engineering must be implemented. Concurrent Engineering is a systematic approach which can be achieved when all design activities are integrated and executed in a parallel manner. The CE approach has radically changed the method used in product development process in many companies. Thus, this paper reviews the basic principles and tools of Concurrent Engineering and discusses how to employ them. Similarly, to ensure a product development process in the CE environment to run smoothly and efficiently, some modifications of the existing product development processes are proposed; these should start from market investigation to detail design.
Malaysia is in the process of modernizing its oil palm plantation management, by implementing geo-information technologies which include Remote Sensing (RS), Geographic Information System (GIS), and Spatial Decision Support System (DSS). Agencies with large oil palm plantations such as the Federal Land Development Authority (FELDA), Federal Land Consolidation and Rehabilitation Authority (FELCRA), Guthrie Sdn. Bhd., and Golden Hope Sdn. Bhd. have already incorporated GIS in their plantation management, with limited use of RS and DSS. In 2005, FELCRA, Universiti Putra Malaysia (UPM) and Espatial Resources Sdn. Bhd. (ESR) collaborated in a research project to explore the potentials of geo-informatics for oil palm plantation management. The research was conducted in FELCRA located in Seberang Perak Oil Palm Scheme. In that research, a tool integrating RS, GIS and Analytical Hierarchy Process (AHP) was developed to support decision making for replanting of the existing old palms. RS was used to extract productive stand per hectare; AHP was used to compute the criteria weights for the development of a suitable model; and GIS was used for spatial modelling so as to generate the decision support layer for replanting. This paper highlights the approach adopted in developing the tool with special emphasis on the AHP computation.
In Malaysia, the use of groundwater can help to meet the increasing water demand. The utilization of the aquifers is currently contributing in water supplies, particularly for the northern states. In this study, quantitative and qualitative assessments were carried out for the groundwater exploitation in the states of Kelantan, Melaka, Terengganu and Perak. The relevant data was acquired from the Department of Mineral and Geoscience, Malaysia. The quantitative assessment mainly included the determination of the use to yield ratio (UTY). The formula was proposed to determine the UTY ratio for aquifers in Malaysia. The proposed formula was applied to determine the maximum UTY ratios for the aquifers located in the states of Kelantan, Melaka, and Terengganu, and were found to be 4.2, 5.2 and 0.6, respectively. This indicated that exploitation of groundwater was beyond the safe limit in the states of Kelantan and Melaka. The qualitative assessment showed that the groundwater is slightly acidic. In addition, the concentrations of iron and manganese were found to be higher than the allowable limits, but the chloride concentration was found within the allowable limit.
In this study, a simple, selective and sensitive method, for spectrophotometric determination of As(III) with gallocyanine as the sensitive reagent was developed. The wavelength of an analytical measurement, for the determination of As (III), using gallocyanine was at 630 nm with an optimum response at pH 2. The RSD for the reproducibility of 100 ppm As (III) was 2.3%. The LOD was 0.04 ppm with linear dynamic range in As(III) concentration of 0.2 - 1.5 ppm. The developed method has been validated against Atomic Absorption Spectrophotometry (AAS). The interference study of several metal ions was carried out and it revealed that that Mn (II) ion was interfered the most.
The concentrations of cadmium, copper, zinc and lead, in the total soft tissues of green-lipped mussel Perna viridis of a wide range of sizes (2-11 cm), were determined from a population at Pasir Panjang. The metal contents (μg per individual) and concentrations (μg per g) of cadmium, lead, copper and zinc were studied in P. viridis to find the relationships with body sizes. Smaller and younger mussels showed higher concentrations (μg per g) of Cd, Pb and Zn than the larger and older ones. The results of the present study showed that the plotting of the metal content, against dry body flesh weight on a double logarithmic basis, gave good positive straight lines; this observation is in agreement with Boyden’s formula (1977). This indicated that P. viridis showed a different physiological strategy for each metal being studied, which is related to age.
Precast concrete technology forms an important part in the drive towards a full implementation of the Industrialized Building System (IBS). The IBS requires building components and their dimensions to be standardized, and preferably cast off site. Slabs are major structural elements in buildings, other than beams and columns. Standardized and optimized slabs can significantly enhance the building industries in achieving the full implementation of the IBS. Nevertheless, this requires computer techniques to achieve standardized and optimized slabs which can satisfy all building design requirements, including the standards of architectural and structural design standards. This study proposed a computer technique which analysed and designed five different types of slabs which will satisfy all the requirements in design. The most commonly used slabs included in this study were the solid one way, solid two way, ribbed, voided and composite slabs. The computer techniques enable the design of the most optimized sections for any of the slab types under any loading and span conditions. The computer technique also provides details for the reinforcements required for the slabs.
Streptococcus zooepidemicus (SZ) is an aerotolerant bacteria and its ability to survive under reactive oxidant raises the question of the existence of a defense system against oxidative stress. As a characteristic of lactic acid bacteria, Streptococcus lacks an ordinary anti-oxidative stress enzyme, catalases and an electron transport chain. Whether this bacterium resists oxidative stress prior to an exposure to a higher level of an oxidizing agent H2O2 in hyaluronic acid fermentation is not known. This paper describes that Streptococcus cells, once treated with lower concentrations of H2O2 (i.e. 0.25, 0.50 and 1.0 mM) at least, were prepared for a subsequent higher concentrations of H2O2 such as 20.5 and 100 mM. At low concentrations (i.e. 0.25, 0.50 and 1.0 mM), H2O2 was found to act as a stimulant for HA synthesis, but it became toxic if presented at a very high level (100 mM H2O2). The highest HA yield to glucose consumed (YHAtotal/glu) was 0.017 gg-1 for the cells pre-treated with 0 mM of H2O2, and then exposed to 20.5 mM H2O2. Thus, this implied that this bacteria might possess a defense mechanism against oxidative stress and that this system was inducible.
Biocatalytic reaction is a type of reaction which uses enzyme or whole-cell as a (bio)-catalyst to achieve a desired conversion, under controlled conditions in a bioreactor. Temperature produces opposed effects on enzyme activity and stability, and is therefore a key variable in any biocatalytic processes. An exothermic biocatalytic reaction, in a continuous-stirred-tank reactor (CSTR), was analyzed where dynamic equations (non-linear differential equations) could be derived from the Michaelis-Menten and Arrhenius equations, by performing mass and energy balances on the reactor. In this work, the effects of the different parameters such as dilution rate, proportional control constant and dimensionless total enzyme concentration, on the stability of the system, were studied. The stability of the reaction could be analyzed, based on the ODE (ordinary differential equation), solved using the numerical technique in MATLAB® and the analytical investigation using Mathematica.® The numerical analysis can be carried out by considering the hase-plane behaviour and bifurcation diagrams of the dynamic equations, while the analytical analysis using Mathematica® can be undertaken by evaluating the eigenvalues of the system. In order to model the operational stability of biocatalysts, modulation factors need to be considered so that a proper design of bioreactors can be done. Temperature, as a key variable in such bioprocess systems, can be conveniently optimized through the use of appropriate models.