19672 research outputs found
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Hydrogeochemical evolution in a tropical cave system; Batu Caves, Peninsular Malaysia
No full textA hydrogeochemical evolution of tropical caves' drip water was carried out at Batu Caves, Peninsular Malaysia. Drip water was analysed to underscore the cave hydrogeochemical evolution. The karst system of Batu Caves is characterized by low water storage capacity due to the high porosity of its weathered soil. A monitoring program was performed on a fortnightly time scale. The tropical environment showed a significant variation on the hydrogeochemical processes in the karst system compared to temperate environments. Drip water was assumed to be fed from a matrix of soil water flow in the absence of recharge. A constant hydraulic pressure was expected as a result of high evaporation in the tropical region and rainfall throughout the year. The mean drip rates varied from 0.02 to 1.02 ml/s and increased coincidently with high water input, and vice versa. The drip water pattern suggested that the drip water differentiated in two flow regimes which are seasonal and seepage flow. Both regimes act differently and control the water infiltration process in the karst system. The water-rock interaction processes involved in the karst system are dissolution, dilution, ionic exchange and prior calcite precipitation (PCP) that lead to saturated SI calcite index. In general, drip water consists of Ca, Mg, and HCO 3 as dominant elements. The source rock deduction analyses strongly suggested that the hydrogeochemical properties of drip water originated from carbonate weathering. The drip and meteoric water were designated as Ca-HCO 3 and Na-CO 3 facies, respectively. Na ion in meteoric water replaced by Ca and SO 4 was exchanged with HCO 3 ; i.e., a Ca-HCO 3 as a result of the ionic exchange. The Ca and Ca:Mg determined that the dissolution rate declined as a result of the drip water reaching its saturation point against PCP. Most of the drip water reached oversaturated values ranging from 0.398 - 1.017. Each drip possessed a unique hydro-geochemistry characteristic which is significantly related to the host rock properties, flow path characteristic, fracture system behaviour, and volume of water input
Analysation of performances of CNC high speed milling machine using multi-walled carbon nanotubes as additives in cutting fluid
No full textHigh quality products produced by computerized numerical control machining has a high demand in the industry due to its effect on product appearance, function, and reliability. In order to improve its quality, the application of nano-cutting fluid system can significantly reduce the cutting forces, surface roughness and cutting temperature as the nanoparticles are known as superior in reducing the friction between the workpiece-tool. In this study, nano-cutting fluid containing multi-wall carbon nanotubes mixed with vegetable oil is developed and applied to the cutting process of aluminium alloy Al6061 which employed minimum quantity lubricant to increase the effectiveness of the nano-cutting fluid. Surface roughness and cutting forces are analyzed by using signal-to-noise response analysis and the analysis of variance (Pareto ANOVA) to determine the optimum parameter of the experiment. The experiment shows the combinations of nanoparticle concentration (A2, 0.2 %), cutting speed (B1, 1000 min -1 ), feed rate (C3, 200 mm/min) and depth of cut (D1, 2 mm) for lowest cutting force, nanoparticle concentration (A3, 0.8 %), cutting speed (B1, 1000 min -1 ), feed rate (C2, 150 mm/min) and depth of cut (D1, 2 mm) for lowest cutting temperature and nanoparticle concentration (A2, 0.2 %), cutting speed (B2, 2000 min -1 ), feed rate (C2, 150 mm/min) and depth of cut (D1, 2 mm) for lowest surface roughness
Effects of Bacillus salmalaya Strain 139SI Inoculation on Yield and Nutrients Uptake of Oil Palm
No full textIntegrating the application of inorganic fertilizer with bacterial inoculants could enhance plant nutrient uptake and increase crop yield. However, their effects on oil palm plantation industry are still less studied. Thus, this study was designed to evaluate the potential of Bacillus salmalaya strain 139SI inoculant on the enhancement of soil fertility, nutrient uptake, yield and eventually, the quality of oil produced. The results demonstrate that inoculation of B. salmalaya strain 139SI produced higher palm fresh fruit bunch (FFB) yield over the untreated. Integrating the 139SI inoculant with inorganic fertilizer resulted in more substantial FFB yield than palm received recommended inorganic fertilizer rate. Enhancement of N level in soil and nutrient uptake was also recorded in strain 139SI inoculated palm. While the number of bunches produced by palm, the oil extraction rate and fatty acid profile shows comparable reading among all treatments. Thus, the results suggest that the application of B. salmalaya strain 139SI inoculant and inorganic fertilizer is effective for improving soil fertility, nutrient uptake and yield of oil palm
Maintenance of lift systems affecting resident satisfaction in low-cost high-rise residential buildings
No full textPurpose: Providing quality low-cost high-rise residential housing for poor households remains a major concern worldwide and especially in Malaysia. Despite government effort to maintain the quality of the housing through the Housing Maintenance Program and 1Malaysia Maintenance Fund Program (TP1M), the maintenance industry is still faced with serious housing quality problems in terms of facilities, one of which is the lift system. As the most expensive and important transportation system in a high-rise building, a lift system requires regular maintenance and inspection to provide safe and effective service to occupants. Unfortunately, most lift systems in Malaysia are not effectively maintained. The purpose of this paper is to examine contributing factors to the breakdown of lift systems, which greatly affect resident satisfaction in low-cost high-rise residential buildings. Design/methodology/approach: Semi-structured interviews were conducted with three stakeholders involved in maintenance management to identify the common causes of lift breakdown. Subsequently, a questionnaire survey was used to investigate resident satisfaction with the system. Findings: The results demonstrate vandalism as the most common cause for the frequent breakdown of lift system in low-cost housing. The study also reveals that there is a significant relationship between system breakdown rate and residents’ satisfaction. Originality/value: The paper concludes with the recommendation that stakeholders, including both maintenance personnel and residents, should commit themselves to ensuring that the use and care of lift system are correct
Temporal and spatial variation of grey water (sullage) properties from commercial and residential catchments
No full textWater pollution has been one of the major concerns in Malaysia and its increasing severity impacts negatively on the sustainability of water resources. It limits the total water availability dramatically due to the exorbitant cost for treating polluted waters and in some cases, polluted waters are not treatable for consumption. Grey water (sullage) is one of the important sources of pollution, which is released from residential and commercial premises into the rivers without prior treatment. Before initiating measures into developing or implementing grey water reuse and treatment systems, it is more appropriate to conduct a detailed study on the discharged grey water quality and characteristics. The present research studies the chemical, biological and physical characteristics of grey water released from residential and commercial premises near the Melana River, which is located at Skudai, Johor, Malaysia. The variations in parameters, namely, BOD, COD, pH and turbidity, with respect to different days and times (temporal) as well as different sampling sites (spatial) are investigated. The results reveal that grey water quality and characteristics are almost similar to those taken from literature and suggest that the treatment of grey water is necessary for intended reuse purposes
Micro-ring resonator made by ion exchange technique and detecting benzene (C6H6), propanol (C3H7OH) and methane (CH4) as cladding layer
No full textWe proposed and investigated the use of a micro-ring resonator in an ion exchange waveguide as a gas/liquid sensor. The ion exchange process in an optical waveguide was simulated using IONEX software, where Ag+ ionic concentrations were deposited on glass substrates. Subsequently, a micro-ring resonator was designed on the ion exchange waveguide as a transducer to sense changes in the effective refractive index using different cladding materials. Benzene, propanol and methane, which exhibit different refractive indices, were used as cladding materials. According to the simulation results, a change in the refractive index causes a change in the spectrum peak intensity as well as a resonance shift. The trace of spectrum change against the refractive index allows the proposed design to be used for gas/liquid sensors. Other micro-ring resonator parameters - FSR, FWHM, Q-factor, finesse and Δf - were also investigated. Results show that changes in the refractive index vary with the parameter. As a result, the proposed design also exhibits great potential for other areas, especially for tunable terahertz generation
A Vehicular License Plate Recognition Framework For Skewed Images
No full textVehicular license plate (LP) recognition system has risen as a significant field of research recently because various explorations are currently being conducted by the researchers to cope with the challenges of LPs which include different illumination and angular situations. This research focused on restricted conditions such as using image of only one vehicle, stationary background, no angular adjustment of the skewed images. A real time vehicular LP recognition scheme is proposed for the skewed images for detection, segmentation and recognition of LP. In this research, a polar co-ordinate transformation procedure is implemented to adjust the skewed vehicular images. Besides that, window scanning procedure is utilized for the candidate localization that is based on the texture characteristics of the image. Then, connected component analysis (CCA) is implemented to the binary image for character segmentation where the pixels get connected in an eight-point neighbourhood process. Finally, optical character recognition is implemented for the recognition of the characters. For measuring the performance of this experiment, 300 skewed images of different illumination conditions with various tilt angles have been tested. The results show that proposed method able to achieve accuracy of 96.3% in localizing, 95.4% in segmenting and 94.2% in recognizing the LPs with an average localization time of 0.52s
Synthesis of 3-(2-furylmethylene)-2,4-pentanedione using DL-Alanine functionalized MCM-41 catalyst via Knoevenagel condensation reaction
No full textTo use as the efficient solid base catalysts, alanine functionalized MCM-41 (Alanine-MCM-41), catalysts viz. 16Alanine-MCM-41 and 8Alanine-MCM-41, were successfully prepared by post-grafting method using MCM-41 synthesized by basic sol-gel method. The synthesized Alanine-MCM-41 catalysts were characterized by several instrumental techniques such as XRD, N2-sorptions and TEM to confirm the standard mesoporous nature. The CHN result shows that the alanine groups have been successfully functionalized on the surface of MCM-41 while the functionalization of alanine groups on MCM-41 were also confirmed by FTIR spectra. The total basic sites of 16Alanine-MCM-41 determined by TPD-CO2 are higher than that of 8Alanine-MCM-41 and enhance to lead the Knoevenagel condensation of furfural and acetylacetone under solvent-free condition. A variety of reaction parameters such as reaction time, temperature, mole ratio and solvents were studied to find an optimum parameter. The Alanine MCM-41 catalysts were successively recovered and reused several times without loss of catalytic activity because of strongly anchored the alanine groups on inner pore of MCM-41, as confirmed by FTIR spectra. Compared to 8Alanine-MCM-41, the 16alanine-MCM-41 gives higher catalytic activity in this reaction because its total base sites lead to produce a major product, 3-(2-furylmethylene)-2,4-pentanedione (FMP) with 100% selectivity using the best parameters like 1:1 M ratio of furfural: acetylacetone, 100 °C and 30 min
Functionalization of medium-chain-length poly(3-hydroxyalkanoates) as amphiphilic material by graft copolymerization with glycerol 1,3-diglycerolate diacrylate and its mechanism
No full textGlycerol 1,3-diglycerolate diacrylate (GDD) was graft copolymerized onto poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) P(3HO-co-3HHX) to render the latter more hydrophilic. Grafting of P(3HO-co-3HHX) backbone was performed using benzoyl peroxide as free radical initiator in homogenous acetone solution. The graft copolymer of P(3HO-co-3HHX)-g-GDD was characterized using spectroscopic and thermal methods. The presence of GDD monomer in the grafted P(3HO-co-3HHX) materials linked through covalent bond was indicated by spectroscopic analyses. Different parameters affecting the graft yield viz. monomer concentration, initiator concentration, temperature and reaction time were also investigated. Water uptake measurement showed that P(3HO-co-3HHX)-g-GDD copolymer became more hydrophilic as the GDD concentration in the copolymer increased. Introduction of hydroxyl groups via grafted GDD monomers improved the wettability and imparted amphiphilicity to the graft copolymer, thus potentially improving their facility for cellular interaction. Thermal stability of grafted copolymer reduced with increased grafting yield. The activation energy, Ea, for the graft copolymerization was calculated at ∼ 51 kJ mol−1. Mechanism of grafting reaction was also proposed
Oral mucosal lesion detection accuracy post lectures and tests in clinical dental students
No full textThe oral medicine field of dentistry comprises learning to diagnose oral soft tissue disease and is taught from the third year of dental school. Despite long-term learning on oral medicine, there are no data on the clinical accuracy of oral mucosal lesion (OML) diagnosis by clinical dental students (CDS). Purpose: to evaluate the effectiveness of oral medicine lectures prior to community service in Tanjung Pandan, Indonesia. Methods: An observational study was done by 60 CDS, divided into 3 groups, who were tested and/or given prior lectures. OML detection was performed by CDS and re-confirmed by an oral medicine specialist. The analyses were done by t-test, ANOVA, and Cohen's Kappa. The results: Out of 615 patients, only 243 patients had OML. There was a significant difference in test scores found between groups with or without prior lectures(P=.026; P=.015). The accuracy and inter-agreement of OML detection was good with substantial agreement (AUC=.825; K=.629); however, there was fair agreement on normal variant oral lesions (AUC=.68; k=.322), and all groups failed to detect and diagnose OPMD lesions (AUC=.501; k=.003). There was a positive correlation between test #2 and AUC OML (R=.845), and with every increase in test score, the accuracy is expected to be .033 higher. Dental student OML knowledge should be upgraded by frequent oral lesion case practice. Further educational strategy is needed to develop dental student's knowledge and skill, so that they can integrate their learning into their practice