In this work, the elastic moduli of silica based borotellurite glass system with compositional formula; [(TeO2)0.7 (B2O3)0.3]1-x (SiO2)x with x= 0.0, 0.1, 0.2, 0.3 and 0.4 was studied using theoretical models. Makishima and Mackenzie, bond compression, Rocherulle, and ring deformation models were employed in the calculation of the elastic moduli, Poisson ratio, packing density, dissociation energy, cross-link density, average stretching force constant and the glass network ring size of the studied glasses. The values of the elastic moduli obtained from the Makishima and Mackenzie model were found to be lower than those obtained from the Rocherulle model and the value from the bond compression model was reported to be highest among the three models. In all the models, the elastic moduli increased with an increase in the concentration of silica in the glass composition. Therefore, it satisfied the original intention of improving mechanical strength to achieve high Young modulus which is .....

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Agarwood is described as fragrance, smelling wood that is usually derived from the trunk of genus Aquilaria The objective of this study was to develop and evaluate four chemical-based inoculants to induce karas tree to form agarwood resin. Four chemical inoculants were applied into 6 years old karas tree (Aquilaria malaccensis) plantations in Slim River, Perak, Malaysia using dripping techniques. The inoculant used were labelled as A, B, C and D. Commercial inoculant was also used for comparison purposes and labelled as K while a healthy tree, act as control was labelled as N. After four months of inoculation, these samples were cut down and discoloured tissue samples were collected. Solvent extraction method using dichloromethane (DCM) was carried out to obtain the resin crude extract from plant tissues of the samples. All chemical formulation used were succesfully stimulated sample trees to produce resin. Inoculant B produced the highest crude extract recovery (5.49%) compared to ino.....

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The number of solar radiations measuring stations in Nigeria has been observed not to effectively describe the necessary variability; as such prediction models are necessary for estimation of solar radiation values using readily available meteorological variables. In this study, solar radiation parameters were determined for Lafia zone, Nasarawa State, Nigeria. Twelve (12) location were carefully selected to avoid sunshine and wind obstruction using a systematic random sampling technique. Three-hour daily measurement (12.00 pm to 2.00 pm) was done on three 12V, 5W solar panels using a pyranometer and the output was estimated using the Angstrom-Prescott RegressionEquation. The continuity in the assembled system was measured using an Avometer. The result revealed that solar radiation intensity was found to range from 165.5 W/m2 to 298.6W/m2 with the mean value of 241.24 W/m2.The highest global solar radiation value of 29.8MJ/m2was observed in April while the lowest value of 16.5MJ/m2was .....

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Centella asiatica (C. asiatica) has been widely used as traditional or alternative medicine for thousand years due to its capabilities to cure various kinds of diseases. This plant has been used widely to prepare numerous kinds of food and beverages in many countries due to its beneficial functional properties. Active compounds that contribute to its antimicrobial properties are madecassic acid, asiatic acid, madecassoside, and asiaticoside. C. asiatica extract can inhibit majorities of foodborne pathogenic and spoilage microorganisms. It also contained antioxidant properties and has been proven to have an insignificant toxicity effect on human consumption. Currently, there is an increase of interest in research development for natural antioxidants and antimicrobial agents to replace the synthetic types in the food industry. This review presents information on the antioxidant capabilities of C. asiatica and its function to inhibit, reduce or minimize microbial growth. The toxicity and .....

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Natural phenomenon and other human activities in the atmosphere have caused serious variations in rainfall which leads to rain-rates that has resulted in the mitigation of signal transmission in satellite communication. This is due to absorption and scattering of the radio waves, resulting in the reduction of the overall link availability. In this study, the cumulative distribution functions (CDFs) for the predicted rain rate and rain attenuation in Abuja, Nigeria was evaluated using the Moupfouma and Chebil models purposely designed for tropical regions. One year data of signal attenuation and amount of rainfall in the study area for 2018 was collected from Nigerian Communication Satellite limited (NIGECOMSAT) and Nigeria Metrological Center (NiMET). The Ajayi (ITU-R P) models alongside with relevant statistics were employed for evaluation of the rain attenuation in the study area. Results show that the highest rainfall value with mean of 128.07 mm was recorded in August while the low.....

915 hits

Log volume estimation is a measurement of the amount of merchantable volume and precise estimation of log volume plays an important role in sustainable forest management. There are several log volume formula which commonly used in estimating the log volume, however, there are significant differences between each formula. Therefore, this paper evaluates the performance of three different log volume formula which are Smalian’s, Huber’s and Bruce’s formula against several log sectional length. The performance of each log volume formula will be evaluated in terms of the bias, precision and accuracy of the estimation. The result shows that Huber’s formula performs the best for log sectional length of 2 m, 4 m, 6 m and 8 m log sectional length. The log sectional length and prediction accuracy is inversely related whereby the shorter the log sectional length, the better the prediction accuracy is...

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Supplier selection is not an easy process as it typically involves multiple criteria and it requires human judgment. Therefore, there is a need to have a better system for supplier selection due to uncertainty and vagueness that exist in dealing with the multiple criteria decision making (MCDM) problem. This study is aimed to identify the important criteria for the selection of the best pharmaceutical raw materials supplier for XYZ Pharmaceutical Manufacturing company by using Fuzzy Analytical Hierarchy Process (AHP) and Fuzzy VIKOR approaches. Furthermore, this paper also presents the comparison results between the two methods in determining the best supplier. Fuzzy theory was used since it provides a right tool to encounter the uncertainties and complexity of decision making environment. This study investigated eight alternative suppliers based on seven criteria evaluated by two decision makers from the company. This study has successfully identified the top three most important crit.....

698 hits

Zinc oxide nanoparticles biosynthesized using two concentrations of Ocimum gratissimum (Og) plant leaf extracts were annealed at two different temperatures. Their UV-Vis absorbance peaks at 372 nm - 375 nm indicate a blue shift in excitonic absorption and their optical energy band gap values were in the range 3.22 eV – 3.31 eV. SEM images show the nanoparticles to be polydispersed and of a wide range of sizes with smaller nanoparticles clustering around bigger micrometer- sized ones with sharp edges. An annealing temperature of 400 ? resulted in the sintering of the nanoparticles but nanoparticles annealed at 250 ? had porous surfaces suggesting a possible use in gas sensor applications. XRD patterns show that the ZnO nanoparticles have the hexagonal wurtzite structure and are of good crystalline structure. Obtained crystallite sizes increased with annealing temperature and were in the range 14 nm to 29 nm. FTIR spectra show phenols, amines and aldehydes as the available reducing age.....

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Kajian  ini  bertujuan  untuk  mengkaji  kepimpinan  berdasarkan  pembesar-pembesar zaman  Kesultanan  Melayu  Melaka  dalam  teks  Hikayat  Melayu  @  Sulalatus  Salatin versi   Tengku  Said  ‘Long  Version’.  Ciri-ciri  kepimpinan  Islam  yang  diperkenalkan Abdul  Wahab  dan   Teori  Kepimpinan  Transformasional  Bass  dan  Avolio  digunakan sebagai   kerangka   konseptual    kajian   ini.   Kajian   ini   juga   menganalisis   ciri-ciri kepimpinan   yang   dimiliki   oleh    pembesar-pembesar   yang   agung   semasa   zaman kesultanan Melaka. Kaedah kualitatif yang  digunakan dalam kajian ini adalah kaedah kepustakaan yang berfokus kepada pembacaan yang teliti ke  atas teks Hikayat Melayu @  Sulalatus  Salatin  versi  Tengku  Said  ‘Long  Version’.  Data   dianalisis  dengan menggunakan kerangka konseptual yang telah dibina dengan menggabungkan ciri-ciri  kepimpinan  Islam  danÂ.....

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Ag-doped flowerlike rutile-phase (Ag-FR) TiO2 film with exposed (1 1 0) and (1 1 1) facet was fabricated by a facile hydrothermal method at 150 °C without additive or capping agent with different Ag content ranging from 0.5 to 2 wt%. This study investigated the influence of Ag content in enhancing the photocatalytic activity of AgFR TiO2 film. The flowerlike structures increased the active area of the TiO2 film. XPS revealed that the concentration of Ti3+-oxygen vacancy defects increased upon doping, while TEM revealed that the (1 1 0) and (1 1 1) are highly exposed facets of rods with flowerlike structure. The effectiveness of the Ag-FR TiO2 film was tested on methylene blue degradation under xenon lamp irradiation. The Ag-FR TiO2 film with 1 wt% Ag resulted in the highest methylene blue degradation, which was 20% higher than degradation by the undoped TiO2. The synergistic effect between both (1 1 0) and (1 1 1) facets and Ti3+-oxygen vacancy from Ag play an important role in reduci.....

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