Assessment of Some Old Earth Dams in Malaysia Through Observation and Computer Simulation

In this study, two earth dams located in Malaysia were studied. The Labong Dam is a non-homogenous earth dam, whilst the Bukit Merah Dam is a homogenous earth dam. The performances of both dams against seepage were studied through the analyses of both observed and simulated phreatic surfaces. Simulations of seepage rate and phreatic surfaces through the dam were conducted by using SEEP/W model. The study showed that the SEEP/W model was able to predict (simulate) both the seepage rates and phreatic surfaces of the homogeneous and non-homogeneous earth dams with a reasonable accuracy. The Absolute Error (AE) between the predicted and observed seepage rates of both dams were found to be 0.03 m3/min to 0.18 m3/min. The average AE in the predicted phreatic surfaces for the maximum and minimum water levels in the reservoir were 0.6 m and 0.38 m for the non-homogeneous dam (Labong Dam), and 0.595 m and 0.75 m for the homogeneous dam (Bukit Merah Dam)

Observation of built-up edge formation on a carbide cutting tool with machining aluminium alloy under dry and wet conditions

This paper presents the morphology of built-up edge (BUE) formation under wet and dry conditions with low and high cutting speeds. The workpiece materials and cutting tools selected for this work were aluminium alloy and canela carbide inserts graded PM25. The cutting tools underwent turning operation machining tests and their performance was evaluated by the flank wear and observation of the tool wear area. The machining tests were conducted at different spindle speeds and feed rates while the cut depth was kept constant. The analysis showed that formation of the BUE was dominant at low cutting speeds in dry conditions, but in wet conditions at high cutting speeds, a better performance was exhibited in terms of wear analysis

Prototype modeling of security system with metal detector

The security system provides the ease to people in order to manage their mall easier and this system is concern on the security of each item. This system will provide not only the items identification but also the anti-theft security. Nowadays, each items produced have a barcode that is printed on its surface as product code. The old system seems not to fully utilize the barcode on each item. This system combines the barcode with electromagnetic security strips in order to reduce the security cost. The barcode strip will be developed in two layers, the barcode and the magnetic strip. The system is working such as the customers self service in the library. The items need to be check at the counter before it been taking out from the store. If the item is not registered then, the alarm will give a warning when it passes through the electromagnetic gate. The LabVIEW program developed by National Instrument is found out to be the best selection as the wave recognition to this system. Identification of patrons and materials by barcode is a reliable technique and gave great service when combined with electro-magnetic security device

Research of biochemical gold recovery method using high-arsenic raw materials

This article contains the results of experiments to recover gold from complex mineral raw materials containing more than 15 % arsenic. Laboratory tests showed that standard cyanidation recovers only 26,4 % of gold into the solution. Additional oxidizing reagents used increase the leaching efficiency and enable to recover more than 40 % of gold during subsequent cyanidation. The efficiency has been established for replacement of cyanide with thiourea and thiosulfate solutions. 79,5 %, i.e. the maximum recovery rate, was found in the experiment with preliminary oxidation with T. Ferrooxidans, a bacterial culture, followed by leaching with a thiourea solution

Optical performance of neodymium nanoparticles doped tellurite glasses

A series of neodymium NPs doped tellurite glass with composition of (TeO2)0.7(B2O3)0.3]0.7 (ZnO)0.3}1- x (Nd2O3 NPs) x (x = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05 mol%) was fabricated via melt-quenching method. Density and molar volume were measured and analyzed for the glass series. The optical properties of neodymium NPs doped tellurite glass were measured by UV–Vis spectrometer, photoluminescence and Z-scan technique. The optical band gap energy of the glass network was in the range of 3.178–3.209 eV. The upconversion emission of the laser glass excited at 800 nm was found in the ultraviolet region. Electronic polarizability, oxide ion polarizability, optical basicity and metallization criterion were calculated. Moreover, linear absorption coefficient, α, nonlinear refractive index ƞ (cm2/W), nonlinear absorption, β (x 10−3) and third order susceptibilities, χ (x 10−6) were measured. The optical efficiency of neodymium NPs doped tellurite glass exhibited excellent properties for its application in laser glass

Research of biochemical gold recovery method using high-arsenic raw materials

This article contains the results of experiments to recover gold from complex mineral raw materials containing more than 15 % arsenic. Laboratory tests showed that standard cyanidation recovers only 26,4 % of gold into the solution. Additional oxidizing reagents used increase the leaching efficiency and enable to recover more than 40 % of gold during subsequent cyanidation. The efficiency has been established for replacement of cyanide with thiourea and thiosulfate solutions. 79,5 %, i.e. the maximum recovery rate, was found in the experiment with preliminary oxidation with T. Ferrooxidans, a bacterial culture, followed by leaching with a thiourea solution

Efficiency study on vertical-finned crystalliser for concentration of carrot juice

Vertical-Finned Crystalliser (VFC) is a new innovation of the progressive freeze concentration method which is applied in concentration of carrot juice. The aim of this research is to observe the efficiency of this newly designed crystalliser in preserving the beta carotene content in the carrot juice concentrate. The crystalliser is equipped with a cooling jacket and extended surface of heat transfer area which makes it possible to obtain high efficiency operation, highly concentrated carrot juice and pure ice layer in the process. The process started with feeding the carrot juice into the crystalliser and the ethylene glycol coolant was pumped into the cooling jacket. Both carrot juice and coolant were circulated in the crystalliser and cooling jacket using two different pumps, until a layer of ice was formed on the inner wall of the crystalliser, including the extended surface/fins. The range of coolant temperature investigated was -6 °C to -12 °C and circulation flowrate of 1,600 mL/min to 2,800 mL/min at constant operation time of 50 min. The efficiency of the process was observed based on the average concentration efficiency value, η (%) and effective partition constant, K using concentration value from the sample absorbance analysis result of UV-Vis spectrophotometer. It was found that the increase in freezing rate (-8 °C) brought about the increase in average concentration efficiency value, η and lower K-value. Meanwhile, the best circulation flow rate was 2,800 mL/min giving higher value of efficiency and lower K-value. The present concentration method using PFC with VFC will be applicable in the industry especially to produce a variety of concentrated liquid food. , N., Azlan, N., Amran, N.A., Zakaria, Z.Y., Ngadi, N., Hashim, R., Jusoh, M

Effect of samarium nanopeprintss on optical properties of zinc borotellurite glass system

he glass series of samarium nanoparticles (NPs) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique. The structural properties of the prepared glasses were investigated by X-ray diffraction (XRD) analysis and FTIR analysis. It was confirmed that the prepared glasses are amorphous in nature. The bonding parameters of the glasses were analyzed by using FTIR analysis and were found the formation of non-bridging oxygen. The density of these glasses were measured and found to be increased with increasing samarium NPs content. The optical absorption spectra of these glasses were revealed that the fundamental absorption edge shifts to higher wavelengths as the content of Sm2O3 (NPs) increases. The optical energy band gap are found to be decreased linearly with an increasing samarium NPs concentration which is due to the formation of non-bridging oxygen in the glass system.KeywordsBorotellurite glass; optical band gap, Samarium nanoparticles

Fatty acid profile and antioxidant properties of oils extracted from dabai pulp using supercritical fluid extraction

The present work was aimed to optimise the supercritical carbon dioxide extraction of dabai oil from dabai pulp and defatted pulp using RSM in comparison with hexane extraction method. Fatty acid profile and antioxidant properties of the extracted dabai oil were also determined. Optimal RSM conditions were 36 MPa pressure, 40°C temperature and 21 min of extraction time. The extracted yields ranged between 14.13% and 15.42%. Supercritical carbon dioxide extracted oils had lower total phenolics, total flavonoids, and antioxidative activities than the hexane-extracted oils. High-performance liquid chromatography results showed that only vanillic, protocatechuic and gallic acids were identified in both hexane and supercritical carbon dioxide extracted oils of defatted dabai pulp. The total saturated fatty acids were higher in hexane-extracted dabai oil as compared to the supercritical carbon dioxide extracted oil, and vice versa for the unsaturated fatty acid. Although supercritical carbon dioxide extracted dabai oils are inferior to the hexane-extracted oils, they are preferred as they are extracted using green technology