Simulation of sub-drains performance using visual MODFLOW for slope water seepage Problem

Numerical simulation technique was used for investigating water seepage problem at the Botanic Park Kuala Lumpur. A proposed sub-drains installation in problematic site location was simulated using Modular Three-Dimensional Finite Difference Groundwater Flow (MODFLOW) software. The results of simulation heads during transient condition showed that heads in between 43 m (water seepage occurred at level 2) until 45 m (water seepage occurred at level 4) which heads measurement are referred to mean sea level. However, elevations measurements for level 2 showed the values between 41 to 42 m from mean sea level and elevations for level 4 between 42 to 45 m from mean sea level. These results indicated an increase in heads for level 2 and level 4 between 1 to 2 m when compared to elevations slope at the level 2 and level 4. The head increases surpass the elevation level of the slope area that causing water seepage at level 2 and level 4. In order to overcome this problems, the heads level need to be decrease to 1 until 2 m by using two options of sub-drain dimension size. Sub-drain with the dimension of 0.0750 m (diameter), 0.10 m (length) and using 4.90 m spacing was the best method to use as it was able to decrease the heads to the required levels of 1 to 2 m

Simulation of sub-drains performance using visual MODFLOW for slope water seepage Problem

Numerical simulation technique was used for investigating water seepage problem at the Botanic Park Kuala Lumpur. A proposed sub-drains installation in problematic site location was simulated using Modular Three-Dimensional Finite Difference Groundwater Flow (MODFLOW) software. The results of simulation heads during transient condition showed that heads in between 43 m (water seepage occurred at level 2) until 45 m (water seepage occurred at level 4) which heads measurement are referred to mean sea level. However, elevations measurements for level 2 showed the values between 41 to 42 m from mean sea level and elevations for level 4 between 42 to 45 m from mean sea level. These results indicated an increase in heads for level 2 and level 4 between 1 to 2 m when compared to elevations slope at the level 2 and level 4. The head increases surpass the elevation level of the slope area that causing water seepage at level 2 and level 4. In order to overcome this problems, the heads level need to be decrease to 1 until 2 m by using two options of sub-drain dimension size. Sub-drain with the dimension of 0.0750 m (diameter), 0.10 m (length) and using 4.90 m spacing was the best method to use as it was able to decrease the heads to the required levels of 1 to 2 m

Performance Investigation of Dual Wavelength Fiber Laser using different SOAs

We investigated the performance of a dual wavelength fiber laser (DWFL) using different types of semiconductor optical amplifiers (SOAs) utilizing fiber Bragg gratings (FBGs) as comb filter. The lasing performances of linear SOA (LSOA), nonlinear SOA (NLSOA) and booster optical amplifier (BOA) at different current setting were observed. LSOA produced the flattest spectrum based on its peak power difference at only 4.5 dB as compared to 66.4 dB using BOA. BOA has the worst flatness because its polarization sensitivity is the highest as compared to LSOA and NLSOA. Overall, the best lasing performance is when LSOA is used due to the lowest peak power difference with high peak power at -17.6 dBm

Growth and proximate composition of tropical marine Chaetoceros calcitrans and Nannochloropsis oculata cultured outdoors and under laboratory conditions

The growth and proximate composition of two marine microalgae, Chaetoceros calcitrans and Nannochloropsis oculata, cultured outdoors under shade (24 to 36°C, 140 μmol/m2/s) and laboratory conditions (environmental chamber, 23°C for C. calcitrans and 20°C for N. oculata, 150 μmol/m2/s) were compared. Outdoor cultures of both C. calcitrans and N. oculata had significantly higher (p < 0.05) biomass, cell count, optical density and specific growth rate compared to the cultures grown under laboratory conditions. Lipid content was significantly higher in C. calcitrans grown outdoors, whereas, protein and carbohydrate composition did not show any significant differences (p > 0.05) between the outdoor and laboratory cultures. In the case of N. oculata, no significant differences (p > 0.05) were found in protein and lipid composition, but carbohydrate was significantly higher (p < 0.05) in the outdoor culture. In addition, the results showed that both C. calcitrans and N. oculata cultures grew faster outdoors, producing more biomass within a shorter period of time. This study illustrated that outdoor culture of microalgae was viable despite the fluctuating environmental conditions.Key words: Growth, proximate composition, Chaetoceros calcitrans, Nannochloropsis oculata, outdoor culture

Bearing performance and damage characteristics of rein-infused thermoplastic 3D woven composites bolted joints

This paper presents a comprehensive study on the single-bolt single-shear (SBSS) and double-bolt single shear (DBSS) lap joint performance of resin-infused thermoplastic 3D fibre-reinforced composite (FRC) in on-axis (0°and 90°) and off-axis (45°) configurations. The bearing performance and failure mechanisms are compared with thermoset 3D-FRC. The resin-infused thermoplastic 3D-FRC bolted joint shows improved bearing performance in terms of higher ultimate bearing strength, stiffness loss strength, and reduced damage severity than its thermoset counterpart. Additionally, this paper presents a detailed study on the intermediate and final failure mechanisms, obtained from scanning electron microscopy of the interrupted and ultimate bearing tests, to understand damage progression in SBSS and BDSS lap joints at the submicron level. The major damage characteristics of a thermoplastic 3D-FRC bolted joint include plastic deformation and plastic kinking at the hole front tip, which improve the bearing capacity and reduce stress concentration, damage severity, and its deleterious effects

Antimicrobial activity of Cosmos caudatus extract against foodborne pathogens

The antimicrobial activity of Cosmos caudatus extract was evaluated against Bacillus cereus(ATCC 33019), Bacillus subtilis(ATCC 6633), Proteus mirabilis (ATCC 21100), Pseudomonas aeruginosa (ATCC 9027) and Candida albicans (ATCC 10231) using the methods as recommended by the Clinical and Laboratory Standard Institute (CLSI). The antimicrobial tests were conducted in term of susceptibility, minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC) and killing-time curve. The results showed that C. caudatus extract was susceptible against all tested pathogens; the inhibition zone ranged from 8.60 mm to 9.83 mm. The MIC and MBC/MFC values were ranged from 6.25 mg/ml-12.50 mg/ml and 12.50 mg/ml-50.00 mg/ml, respectively. Mean while, killing-time curves showed that C. caudatus extract can killed the B. cereus, B. subtilis, P. mirabilis, P. aeruginosa and C. albicans at concentration of 8 MIC for 2 h, 4 MIC for 2 h or 2 MIC for 2 h, 8 MIC for 4 h, 4 MIC for 0.5 h and 4 MIC for 1 h, as respectively. Findings indicated that C. caudatus extract has the potentiality to develop as a natural antimicrobial agent

Seasonal and spatial dynamics of the primary vector of plasmodium knowlesi within a major transmission focus in Sabah, Malaysia

Background The simian malaria parasite Plasmodium knowlesi is emerging as a public health problem in Southeast Asia, particularly in Malaysian Borneo where it now accounts for the greatest burden of malaria cases and deaths. Control is hindered by limited understanding of the ecology of potential vector species. Methodology/Principal Findings We conducted a one year longitudinal study of P. knowlesi vectors in three sites within an endemic area of Sabah, Malaysia. All mosquitoes were captured using human landing catch. Anopheles mosquitoes were dissected to determine, oocyst, sporozoites and parous rate. Anopheles balabacensis is confirmed as the primary vector of. P. knowlesi (using nested PCR) in Sabah for the first time. Vector densities were significantly higher and more seasonally variable in the village than forest or small scale farming site. However An. balabacensis survival and P. knowlesi infection rates were highest in forest and small scale farm sites. Anopheles balabacensis mostly bites humans outdoors in the early evening between 1800 to 2000hrs. Conclusions/Significance This study indicates transmission is unlikely to be prevented by bednets. This combined with its high vectorial capacity poses a threat to malaria elimination programmes within the region. Author Summary The first natural infection of Plasmodium knowlesi was reported 40 years ago. At that time it was perceived that the infection would not affect humans. However, now P. knowlesi is the predominant malaria species (38% of the cases) infecting people in Malaysia and is a notable obstacle to malaria elimination in the country. Plasmodium knowlesi has also been reported from all countries in Southeast Asia with the exception of Lao PDR and Timor Leste. In Sabah, Malaysian Borneo cases of human P. knowlesi are increasing. Thus, a comprehensive understanding of the bionomics of the vectors is required so as to enable proper control strategies. Here, we conducted a longitudinal study in Kudat district, Sabah, to determine and characterize the vectors of P. knowlesi within this transmission foci. Anopheles balabacensis was the predominant mosquito in all study sites and is confirmed as vector for P. knowlesi and other simian malaria parasites. The peak biting time was in the early part of the evening between1800 to 2000. Thus, breaking the chain of transmission is an extremely challenging task for the malaria elimination programme

Experimental of Hot Machining for Stainless Steel 316L Cutting Process

Stainless Steel 316L having excessive tensile power and resistance to temperature with excessive manganese content resulting high roughness during cutting process. The problem occurs when machining process conduct at hot conditions to soften the workpieces. To study the cutting parameters effect on surface quality and tool wear length, different temperatures were used for turning process in this study. The experiment conducted with hot machining process at temperature conditions at 200, 300 and 400 °C. The parameters of this experiment are cutting speed of 76–149 mm/min and feed rate of 0.11–0.22 mm/rev with constant value of depth of cut. The results showed the surface roughness affects the tool wear when machining at high feed rate and cutting speed compared to lower parameters conditions. The heating source temperature affects the surface roughness, area roughness parameter and tool wear in cutting process. In conclusion, the surface quality and tool wear improved at high feed rates and cutting speeds compared to lower parameters settings

Simulation of U-shaped plastic optical fiber ethanol sensor

The prediction of optical loss in different bending diameter of U-shaped POF sensor towardvariation of ethanol’s refractive indices was investigated using ray-tracing method perform byZemax software. It can provide information on how the propagation ray is perturbed bydifferent bending diameter of U-shaped POF. There are five designs of POF models werepre-drawn with different bending diameter; 2.0cm, 2.5cm, 3.0cm 3.5cm and 4.0cm. From theresults, U-shaped with 2.5 cm bending diameter has shown the most sensitive bendingdiameter as compared to the rest. Either with the presence of cladding layer or not thesensitivity detected was 0.014 x10-4 Watts/Vol%Keywords: ray-tracing; Zemax software; U-shaped POF sensor; ethanol sensor

Fuzzy logic controlled miniature LEGO robot for undergraduate training system

Fuzzy logic enables designers to control complex systems more effectively than traditional approaches as it provides a simple way to arrive at a definite conclusion upon ambiguous, imprecise or noisy information. In this paper, we describe the development of two miniature LEGO robots, which are the line following and the light searching mobile robots to provide a better understanding of fuzzy logic control theory and real life application for an undergraduate training system. This study is divided into two parts. In the first part, an object sorter robot is built to perform pick and place task to load different colour objects on a fuzzy logic controlled line following robot which then carries the preloaded objects to a goal by following a white line. In the second part, an intelligent fuzzy logic controlled light searching robot with the capability to navigate in a maze is developed. All of the robots are constructed by using the LEGO Mindstorms kit. Interactive C programming language is used to program fuzzy logic robots. Experimental results show that the robots has successfully track the predefined path and navigate towards light source under the influence of the fuzzy logic controller; and therefore can be used as a training system in undergraduate fuzzy logic class