A new method called parallel R-point explicit block method for solving a single equation of higher order ordinary differential equation directly using a constant step size is developed. This method calculates the numerical solution at R point simultaneously is parallel in nature. Computational advantages are presented by comparing the results obtained with the new method with that of the conventional 1-point method. The numerical results show that the new method reduces the total number of steps and execution time. The accuracy of the parallel block and the conventional 1-point methods is comparable particularly when finer step sizes are used.
In an attempt to synthesize new solid solutions and search for better performance materials, pentavalent cation dopants were introduced into the non stoichiometric BZN cubic pyrochlore, Bi3Zn1.84Nb3O13.84. Extensive solid solutions were formed in Bi3Zn1.84Nb3-xDxO13.84 with limit at x = 3 and 2.6 for D = Ta and Sb, respectively. This illustrates the possibility of cation-exchange solid solutions due to similarity in dopants’ ionic radii. The elemental analysis confirmed the stoichiometry of doped materials with no deleterious Bi2O3 loss. Ta / Sb doped samples were highly resistive with activation energies ranging from 1.2 - 1.9 eV. Temperature coefficient of capacitance, TCC, decreased from -396 ppm / oC to ~ -180 ppm / oC and ~ -90 ppm / oC for both end members, respectively.
Cu2O films were grown on n-Si substrates via the sol-gel spin-coating method. The films were annealed under 5% H2 + 95% N2 atmosphere at 350°C, 450°C and 550°C. Diffractogram obtained by the grazing angle x-ray diffractometry showed that the crystallinity of the films increased with increasing annealing temperature. Scanning electron microscopy micrographs revealed that the Cu2O films contain grains of irregular size indicating that the film growth followed the Volmer-Weber growth mode. The micrographs showed the size evolved from irregular shapes with average size of 100 nm at 350°C into rectangular shapes with average size of 200 nm at 550°C. Optical reflectance for 450°C and 550°C film increased gradually at wavelength 480 nm. Higher reflectance for the 450 °C film might be due to better coverage of the film. It also showed that optical absorption occured at wavelength below 480 nm.
The electrical and microstructural properties of (La1-xPrx)1/2Ba1/2MnO3 (x = 0.000, 0.167, 0.333, 0.500, 0.677, 0.833 and 1.000) compounds, prepared by the solid state reaction, have been investigated. The electrical property has been determined by using standard the four-point probe resistivity measurement with a temperature range of 30 K to 300 K. By increasing the Pr doping, the metal-insulator transition temperature (Tp) shifted to lower temperatures, which are 254, 248, 228, 220, 196, 180 and 158K for x = 0.000, 0.167, 0.333, 0.500, 0.677, 0.833 and 1.000, respectively. Using several theoretical models, it has been concluded that the metallic (ferromagnetic) part of the resistivity (ρ) (below TP) fits well with the equation ρ = ρ0 + ρ2.5T2.5, indicating that ρ0 is due to the importance of grain and domain boundary effects, a second term ~ ρ2.5T2.5 appears that might be attributed to electron-electron scattering. The scanning electron microscope (SEM) micrographs show the grains size decreases as the level of porosity increases, which contributes to the increase resistivity.
The values of beam quality correction factor kQ that were experimentally determined from year 2002 to 2008 were analysed. As kQ is the function of ionization chamber and beam quality, the analysis were based on three cases namely (a) kQ(NE2571, 6 MV x-rays) that were determined from 17 measurements in the duration of 69 months at 6 radiotherapy centres, (b) kQ(NE2571, 10 MV x-rays) from 7 measurements in the duration of 12 months at one radiotherapy centre, and (c) kQ(NE2581, 6 MV x-rays) from 5 measurements in the duration of 5 months also at one radiotherapy centre. The purpose is to examine, in each case, the variation kQ for all the measurements. In other words, to see variation kQ with time. Results obtained are 0.993(NE2571, 6 MV), 0.986(NE2571, 10 MV) and 0.986(NE2581, 6 MV). This shows that in each case, despite the difference in the experimental data in getting kQ for all measurement, kQ remains constant with time. Reasons for this are explained.
The importance of intercomparison programme for radiation therapy dose delivery at radiotherapy centres (RC) has widely been reported. We at Nuclear Malaysia Agency (NM) intend to develop a national level intercomparison programme in terms of absorbed dose to water Dw. We started with one RC which has voluntered to participate in the programme in the dose delivery of 6 MV x-ray beam. Two types of comparison were made to get the accuracy. Type I is based on the measured value of the Dw at reference depth, Dw(zref)mea : RC results was compared with NM, in which NM results was taken as a standard. Type II is based on calculated value the Dw(zref), Dw(zref)cal : both NM and RC results were compared with Dw(zref)cal, in which Dw(zref)cal was taken as a standard. Two on-site measurements were made at this centre to check for results consistency and to get the average accuracy. Results obtained were consistent for the two measurements and the average values in the accuracy are within the acceptable accuracy limit of ± 3%, namely Type I: 1.10 ± 0.58 % for the RC, and Type II: 0.99 ± 0.60 % and −0.11 ± 0.26% respectively for the RC and NM.
Acetone-butanol-ethanol (ABE) fermentation from Palm Oil Mill Effluent (POME) by C. acetobutylicum NCIMB 13357 in an oscillatory flow bioreactor was investigated. Experimental works were conducted in a U-shaped stainless steel oscillatory flow bioreactor at oscillation frequency between 0.45-0.78 Hz and a constant amplitude of 12.5 mm. Fermentations were carried out for 72 hr at 35oC using palm oil mill effluent and reinforced clostridia medium as a growth medium in batch culture. Result of this investigation showed that POME is a viable media for ABE fermentation and oscillatory flow bioreactor has an excellent potential as an alternative fermentation device.
A new series of lanthanum dialkyldithiocarbamate complexes with 1,10-phenantroline were successfully synthesized using in situ methods. These complexes were characterized using elemental analysis, infrared, thermogravimetric analysis and conductivity. Microelemental analysis data were in agreement with the general formula La(S2CNR’R”)3phen (R’ = ethyl, methyl; R” = butyl, heptyl, isopropyl, isobutyl, benzyl and cyclohexyl; phen = 1,10-phenantroline). Infrared spectra of complexes showed the thioureide n(C-N) bands were in the region of 1450 - 1482 cm-1. The single n(C-S) bands appeared in the region of 959 – 997 cm-1 and n(C-H) bands in the region of 2918-2955 cm-1. The crystal structure of tris(N,N-ethylbenzyldithiocarbamate)(1,10-phenantroline)lantanum(III) adopts an orthorombic system (space group Pccn) with a distorted dodecahedron geometry with a = 19.865(5) Å , b = 42.803(10) Å, c = 10.657(3) Å, a = b = g = 90o and Z = 9. Three dithiocarbamates and one phenanthroline ligands were coordinated to the central La atom in bidentate manner.
This study was carried out to determine the properties of coatings made from wheat, rice and sago flour when fried under different frying temperature and pressure during the initial period of deep-fat frying. Three types of batter made from wheat, rice and sago flour were prepared by mixing each flour with water at a ratio of 1:1.2 (flour: water). Poultry nuggets were dipped in the prepared batter and fried for 0, 6, 18 and 30 seconds at three frying temperatures (150, 165, 180°C) and two frying pressures (102 and 156 kPa). Results showed that the frying pressure applied did not produce any significant effect on moisture content, normalized moisture loss and fat content up to 30 seconds of frying. All parameters except moisture content of the coating region were significantly (p<0.05) affected by flour type. Coating from sago flour produced the highest normalized moisture loss and fat content compared to other flour.
A study was carried out to evaluate the effects of frying pressure (102 and 156 kPa) and temperature (150, 165 and 180°C) on sensory characteristics of chicken nuggets coated with wheat, rice and sago flours. Batters from wheat, rice and sago flours were prepared by mixing each flour with water at a weight ratio of 1:1.2 (flour: water). Chicken nuggets were dipped in the prepared batters and fried at the different pressure and temperature for 7 minutes. Sensory evaluation was done using trained panelists (n=7) with two replication. Attributes assessed were color, aroma, coating thickness, adhesiveness, hardness, crispness, oiliness, juiciness and overall acceptance. Results showed that using different frying pressures and temperatures did significantly affect (p<0.05) all the sensory attributes of chicken nuggets coated with wheat, rice and sago flours. It was observed that coated chicken nuggets fried at a pressure of 156 kPa and temperature of 165°C was most preferred by the trained panellists.
The size frequency distribution for age structure and length weight relationship of three species of the genus Acetes from the coastal waters of Malacca, Peninsular Malaysia are reported. The length frequency distribution for A. indicus suggested that the population consisted of two dominant age groups with mean at 20.80 (± 2.42) mm and 29.85 (± 2.79) mm of total length, respectively. The population of A. japonicus consisted of maximum two age groups, with means of 15.18 (± 0.90) mm and 21.56 (± 1.03) mm of total length. The population of A. intermedius also consisted of maximum two age groups, with means of 19.18 (± 2.45) mm and 26.92 (± 2.82) mm of total length. The positive allometric nature of growth for A. indicus was observed in the coastal waters of Malacca. But isometric nature of growth was found in combined sexes of A. japonicus. The positive allometric nature of growth was observed in female and both sexes of A. intermedius. There were significant difference between males and females size-frequency distribution of A. indicus (Kolmogorov-Smirnov test: dmax= 0.42, P < 0.001), A. japonicus (Kolmogorov-Smirnov test: dmax = 0.39, P < 0.001) and A. intermedius (Kolmogorov-Smirnov test: dmax = 0.40, P < 0.001). The significant differences were observed between mean total length of female and male of A. indicus, A. japonicus and A. intermedius (t-test, P < 0.001).
The molecular genetic marker, minisatellite locus D1S80 (1p35-p36), is a highly polymorphic variable number of tandem repeats (VNTR). Its polymorphic nature allows for phylogenetic studies, forensic analysis, genetic maps construction and paternity testing to be performed. A study of the hypervariable locus D1S80 was conducted to determine the allele frequency and distribution of this locus in modern Malay in Sarawak population. The polymerase chain reaction technique was employed and results were analysed on polyacrylamide gel. A total of seventy-six DNA samples of unrelated Malay individuals in UNIMAS were collected and examined. The VNTR analysis of the D1S80 locus demonstrated the presence of 17 alleles in the Malay population. Allele with the size of 577 bp (27 repeats) was determined to be the most common in the sample population with the frequency of 0.1641, followed by allele with the size of 561 bp (26 repeats) and 529 bp (24 repeats) whose frequency is 0.1172 and 0.1094, respectively. The smallest allele is allele with the size of 465 bp (20 repeats) whereas the largest is allele with the size of 753 bp (38 repeats). The sample population exhibited 57.8% heterozygosity.
This study attempts to trace changes in the wet spells over Peninsular Malaysia based on the daily rainfall data from 32 selected rainfall stations which include four sub-regions; northwest, west, south and east, for the period of 1975 to 2004. Six wet spells indices comprising of the main characteristics (maximum, mean, standard deviation), the persistency of two consecutive wet days and the frequency of the short and long duration of wet spells will be used to identify whether or not these indices increase or decrease over Peninsular Malaysia during the monsoon seasons. The study indicates that the eastern areas of the peninsula could be considered as the wettest areas since almost all the indices of wet spells over these areas are higher than over the other regions during the northeast monsoon (NE). The Mann-Kendall (MK) trend test revealed that almost all of the stations located in the eastern areas of the peninsula exhibited a positive trend in the mean, variability and persistency of wet spells indices during the NE monsoon, while a negative trend was observed during the southwest monsoon (SW) in these areas. Moreover, these indices showed a positive trend, and at the same time a decreasing trend was observed in the frequency of the long wet spells in most stations located over the west coast of Peninsular Malaysia during the SW monsoon for the period of 1975 to 2004.
MeSH terms: Malaysia; Rain; Seasons; Time Factors; Cyclonic Storms
Several series of trawl survey was carried out in the coastal waters of southeastern South China Sea using commercial trawler. Six species of ponyfishes were caught throughout the study. Adult fish species were examined for their systematic differences. Based on systematic differences, a pictorial description of each species was built up. Detail population growth of dominant species was estimated using the allometric regression analysis of length (L)-weight (W) relationship (W= aLb). The results showed that the regression coefficient b was 3.337±0.105 for Photoplagios stercorarius, 2.530±0.298 for Photopectoralis bindus, 2.690±0.330 for Secutor insidiator and 2.211±0.507 for Gazza minuta respectively. Stomach contents analyses revealed feeding guilds of each species of fishes. Mean trophic level for P. bindus was 3.222±0.491, G. minuta was 2.753±0.291, P. stercorarius was 2.662±0.316, S. insidiator was 2.865±0.298, Leiognathus jonesi was 2.490±0.267 and Leiognathus oblongus was 2.413±0.296 respectively. The mean value of RLG for P. stercorarius was 0.8740±0.0576, G. minuta was 0.5135±0.0942 and P. bindus was 1.1399±0.2611. Reproductive biology of the selected species of ponyfishes showed that the gonads were mono-lobed with maturing and matured oocytes stages at time of sampling. A mean value of GSI for P. bindus was 4.002±0.650, P. stercorarius was 2.540±0.430, S. insidiator was 5.638±1.114, Gazza minuta was 0.382±0.070, L. oblongus was 2.925±0.820, L. jonesi was 1.578±0.821 and Nuchequula decora was 2.569±1.451 respectively.
Nephrolepis cordifolia rhizome (sword fern) juice was investigated for diuretic activity in wistar rats. Different parameters viz. total urine volume (corrected for water intake during the test period), urine concentration of electrolytes such as sodium, potassium and chloride have been evaluated. Rhizome juice of Nephrolepis cordifolia (100 mg/kg), the reference drug, furosemide (20 mg/kg) was administrated orally to male Wistar rats and their urine output was quantitated at several intervals of time after the dose. After single dose of the rhizome juice of Nephrolepis cordifolia, urine output was significantly increased. Increase in urinary levels of Na+, K+ and Cl- was also observed after the administration of rhizome juice.
Population in urban centers in Kenya is increasing rapidly due to rural urban migration in search of better paying jobs. This migration has resulted in unauthorized settlements in the various urban centers. The income per capital of these people is less than a dollar a day. The amount of money is inadequate for survival and this has resulted into cultivating on open grounds for food crops. Unfortunately, these slums have come up along rivers, which carry, wastewater from household and industries. This wastewater is rich in heavy metals and the inhabitants of these areas use this contaminated water for irrigating their crops. The food crops from such areas have very high levels of heavy metals. The present study has screened Zea mays, Commelina bengalensis and Amaranthus hybridus for their ability to bioaccumulate these metals from contaminated soils using atomic absorption spectrophotometer (AAS). The results obtained showed that the C. bengalensis has high potential for removal of Cu, Pb and Cd metals as compared to the Zea mays and Amaranthus hybridus even though, results showed that C. bengalensis has a low potential for the removal of Zn as compared to Zea mays and Amaranthus hybridus.
MeSH terms: Zea mays; Kenya; Lead; Population Dynamics; Poverty Areas; Soil; Water Pollution; Zinc; Crops, Agricultural; Metals, Heavy; Amaranthus; Commelina; Rivers; Waste Water
This research, compares the observed seismogram of the PNG earthquake, C051099C with its synthetics in UGM, Wanagama, Indonesia, PMG, Port Moresby, PNG and CHTO, Chiang May, Thailand. The synthetic seismogram is calculated using preliminary earth model, which are the IASPEI91 and the anisotropic version of PREM. The seismogram comparison is conducted after imposing a low pass filter whose corner frequency is fixed at 20 mHz. We have found a real discrepancy on the travel time and waveform of some wave phases, namely P, S and Rayleigh and Love surface waves, by seismogram comparison in time domain. To correct the discrepancies, we need to adjust the earth structures, which include the depth of the Moho reflector, the velocity gradient of bh, and the propagation velocity of the P and S waves. The correction has been conducted in the earth layering system from the upper mantle down to the CMB, so that the excellent seismogram fitting was obtained for nearly all phases of the targeted waves. The used wave length for analysing is about 150 km. It turns out that the waveform of the body and surface waves is sensitive to the change of velocity structure. The analysis of repetitive ScS depth phases at closer distance stations gives better opportunity to investigate the S velocity structure near the CMB, something not used by other seismologists.
Silicon nanomaterial was prepared using the peroxide/acid/salt technique in which an aqueous silicon-based salt solution was added to H2O2/HF etchants. In order to optimize the experimental conditions for silicon nanomaterial production, the amount of nanomaterial produced was studied as a function of the volume of the silicon salt solution used in the synthesis. A set of samples was prepared using: 0, 5, 10, 15, and 20 mL of an aqueous 1 mg/L metasilicate solution. The area under the corresponding peaks in the infrared (ir) absorption spectra was used as a qualitative indicator to the amount of the nanomaterial present. The results indicated that using 10 mL of the metasilicate solution produced the highest amount of nanomaterial. Furthermore, the results demonstrated that the peroxide/acid/salt technique results in the enhancement of the production yield of silicon nanomaterial at a reduced power demand and with a higher material to void ratio. A model in which the silicon salt forms a secondary source of silicon nanomaterial is proposed. The auxiliary nanomaterial is deposited into the porous network causing an increase in the amount of nanomaterial produced and a reduction in the voids present. Thus a reduction in the resistance of the porous layer, and consequently reduction in the power required, are expected.
Molybdenum disulfide (MoS2) is a VI – VI compound semiconductor has hexagonal structure useful for high temperature lubricant. Polycrystalline films are electrodeposited cathodically on tin oxide (SnO2) coated conducting glass substrates. The deposited films are characterized by various techniques includes the X-ray diffraction analysis, where the structure of the films is identified as hexagonal and the lattice parameters are a = b = 3.153 Å and c = 12.279 Å which are in good agreement with standard report values. From optical analysis, the bandgap value is calculated as 1.68 eV with indirect bandgap nature. From scanning electron micrographs, the surface appears to be comparatively granular with grains in irregularly shaped. The thickness of the MoS2 films was calculated in the region 0.80 – 0.82 mm by using weight gain method. From Mott-Schottky plots the films are found to be n-type and the semiconductor parameters of the film are derived. From the photoelectrochemical cell studies the fill factor, open circuit voltage, short circuit current and efficiency are calculated.
Rheological properties of highly concentrated oil-in-water (O/W) emulsions (HCEs), formed by mixing palm-based nonionic surfactant, C12E6 (HLB = 11.7, CMC = 25μM), water and olive oil volume fraction ≥78vol% were investigated. Samples with lower oil volume fraction (<85%) and surfactant concentration (<8%) exhibited polydispersity of broader droplet size distribution (DSD). In contrast, samples with higher oil volume fraction (>85%) and surfactant concentration (>8%) displayed monodispersity of narrower DSD. The average droplet size decreased with increasing oil volume fraction and surfactant concentration. All frequency sweep experiments exhibited higher G’ than G”, representing the predominantly elastic nature of HCEs. The crossover of the ascendant and descendant flow curves of HCEs with higher oil volume fraction (>85%) and surfactant concentration (>8%) implied a structural build-up that could give rise to very high stability. The high stability was confirmed through accelerated stability test at 40oC for three months.