Abstract: This paper provides an overview of the use of green solvents for oil extraction from natural product using soxhlet extraction and supercritical fluid extraction (SFE) methods. In terms of qualitative and quantitative determinations on the extracted oils, the use of green solvents was comparable with n-hexane. For soxhlet extraction method, the integration of microwave application into the soxhlet at their optimum conditions has shown improvement in oil yield, oil quality, solvent consumption and extraction time. SFE using CO2 also revealed promising results as soxhlet extraction but apparently it involved high operating cost and difficult to control. Despite of that, all the studies successfully demonstrated the suitability of green solvent as an alternative to petroleum driven solvents for extraction of oils from natural products.
Abstract: Elemental doping of titanium dioxide with nitrogen and carbon were investigated in this study to get the modified photocatalyst working under visible light. Doped and codoped photocatalyst samples were synthesized by solgel method using titanium isopropoxide, ammonium nitrate and acetylacetone as precursors with the dopant concentration and calcination temperature fixed at 0.75% and 600°C respectively. Synthesized photocatalysts were characterized by XRD, FTIR and FESEM to check the existence of anatase phase, presence of dopants and formation of fine particles respectively. The effectiveness of the synthesized photocatalysts was measured by performing a standard batch photodegradation test with methylene blue as a model pollutant under ordinary visible light. The photocatalytic degradation efficiencies were found to be affected by the presence of dopant elements. The codoped photoctalyst (N-C-TiO2) exhibited the highest photocatalytic activity as it resulted in 91.3% degradation of methylene blue over 180 minutes of irradiation time.
Abstract: The revised Malaysian Urban Stormwater Management Manual (MSMA) eludes the importance of tidal backwater analysis in the engineering of lowland river drainage. Tidal gates and flood gates can only be adequately designed if a detailed investigation of the dynamic interactions of tidal high water and storm discharge be conducted. We propose a numerical and laboratory investigation of the lower Klang River in order to better understand the independent and joint effects of these factors to river flood stage.
Abstract: This paper presents 4-D high resolution electrical resistivity tomography study for slope monitoring using two optimized (modified) arrays of the Wenner-Schlumberger and Pole-Dipole. These optimized resistivity arrays give a total of 2052 number of datum points from each data acquisition set. These two optimized were used because they have more datum points compared to their original arrays. Perhaps these optimized arrays were able to resolve the subsurface structures from surface areas. Inversion results from the computer (mathematical models) suggested that these optimized arrays were able to give in imaging the Earth’s subsurface structures and characterization at different period of time. Furthermore, in this paper, we are presented merging data levels in order to give high resolution in electrical resistivity tomography. Even though the time taken for data acquisition using this technique is twice, the outcome is compromised and reliable which helpful in the Earth’s subsurface interpretation.
Abstract: Ground-based solar photometer measurements were utilized in the ambiance of Universiti Sains Malaysia (USM) Penang and Universiti Teknologi MARA (UiTM) Penang during September-November 2013 with a specific end goal to portray the characteristics of the local atmospheric environment. This both sites were established as being component of the collaborative work of the Seven South East Asian Studies (7SEAS) regional aerosol measurement project. This study concentrates on the Angstrom exponent (α), that is the gradient of the logarithm of the aerosol optical depth (AOD) against the logarithm of the wavelength as well as being commonly used to characterize the wavelength reliance of AOD and to furnish some critical data on the aerosol size distribution. In most situations fine mode aerosols appear to be the predominant category with marginally substantial contributions of coarse mode particles resulting from the particle growing, blending processes with other aerosol types, precipitation factors and relative distance to the seashore.
Abstract: A one-third scale single unit of 3-storey tunnel form building with foundation beam was designed, constructed and tested under out-of-plane lateral cyclic loading. This building was designed according to BS8110 with no provision for seismic loading. Tunnel form building was initially tested at ±0.01% , ±0.1%, ±0.25%, ±0.5%, ±0.75%, ±1.00%, ±1.25% and ±1.5% drifts until the structure lost its lateral strength (strength degradation). Then, the specimen was repaired and retrofitted using steel plate and angle which was positioned at the wall-slab joints that had suffered severe damages. A similar drift of displacement before retrofitting was repeated for the specimen after being retrofitted. Visual observation of damages, hysteresis loops, stiffness, ductility and equivalent viscous damping (EVD) of the specimen were analyzed and compared before and after retrofitting. The proposed retrofitting technique has increased its lateral strength by 26%. Fewer cracks occurred after retrofitting the specimen compared to before retrofitting. It can be concluded that steel plate and angle can strengthen the wall-slab joint and this method can be used to retrofit the tunnel form building if it had been damaged caused by earthquake excitations.
Abstract: Lightweight concrete (LWC) is one of the favourable concrete to be used as it has low density with acceptable high strength, high durability, and toughness. In order to produce LWC, it is required special material such as expanded polystyrene (EPS) beads and steel fiber to be added into the design mix concrete. As known, EPS beads have zero strength. Meanwhile, the significant of steel fiber is to reduce micro and macro crack propagation. Therefore, pull out test were carried out to measure the bond strength between reinforcement bar and three series of concrete mix design which are normal concrete, EPS-LWC and EPS-LWC enhanced with steel fiber. Concrete adhesion and bearing deformation of reinforcing bar against the concrete are the two main mechanisms that influence the strength of bond in the steel reinforced concrete. Deformation will increase when the bonding stress increase. Normal concrete series shows the higher average bonding stress which is 531.22 kPa compared to others series concrete mix. Meanwhile, bonding stress of EPS-LWC mix is 174.54 kPa which is higher than EPS-LWC enhanced with steel fiber mix. Even though the present of the steel fibre can increase the strength of the LWC, but it effects to the bonding strength between reinforcement steel rod and concrete. There are two improtant factor in bonding determination which are volume fraction and aspect ratio of the steel fiber. Segregation will increase when the aspect ratio of steel fiber increased. Besides, the workability becomes low. This present study used types of hooked end steel fiber with 60 mm length and aspected ratio is 0.75. While the size of the cylindrical is 300 mm x 150 mm. The position of the steel fiber in the specimens is too compact and presenting the air voids. Consequently weaken the bonding strength between concrete and reinforcement bar.
Abstract: The paper presents an evaluation of medium-rise reinforced concrete building in Johor which is subjected to low intensity earthquake effects. Even-though Malaysia is outside the earthquake region, the country had experienced and did suffer from major cases due earthquake in the past like tsunami. Engineers should concern and consider the loading for reinforced concrete building due to earthquake in the building design procedure. The study addresses the performance of critical frame reinforced concrete building when subjected to earthquake motion. The building of Marlborough College Malaysia chooses as model. The building was analyzed using Finite Element Modelling (FEM) using IDARC (2D) with respect to various earthquake intensities obtained from Time History Analysis (THA) data. The yield point at the beam-column connections was analyzed to determine the damage index and damage level of the building subjected to the various earthquake intensities. The building performed the early yielding point at 4.2650 sec for beam element at the intensity of 0.15g. Based on the results, it was found that the critical frame of Condominium Marlborough College Malaysia can stand an earthquake occurrence with intensity up to 0.20g. There is no structural damage some non-structural damage is expected in the non-linear analysis of modal frames. The building was also categorized as the one in the light damage level.
Abstract: This paper reports the investigation on the fire resistance performance of reinforced concrete column with embedded permanent formwork from woodwool board (WWCB). A series of slender column embedded with and without WWCB with cross-sections 200 mm x 200 mm for column without WWCB and 300 mm x 300 mm with embedded 50 mm thick WWCB. The height of the slender column was 2000 mm. The fire resistance test was performed in accordance with BS 476-22:1987 for two (2) hours fire exposure. The fire resistance test for the embedded column with WWCB was classified as “good” in resisting fire and heat transfer.
Abstract: A significant increase in demand for services will mean volatility axial load applied to structural elements, particularly the railway station when a train distributions narrow peak intervals. The prestressed concrete runway is one of the major structural component of the train and was showing fatigue cracking as a result of this change. Any local information that link fatigue fracture in concrete directly to understand the fatigue performance are limited. It is important that the load can be simulated real train closed to those under service load. This work aims to study the ability to withstand fatigue loading during services and the flexural behavior of sleeper under low velocity impact loading. The outcome of the work is to produce a harmonic function that will express the variable amplitude waveform through numerical modeling constant amplitude. This is involved a PSC responses due to train wheel loading of the commuter train.