Influence of modified air on combustion characteristics in meso-scale vortex combustor

The need to supply power for miniaturized mechanical devices opens exciting new opportunities for combustion, especially in the field of micro-power generation. Because of the need for power supply devices with high-specific energy (small-size, low weight, long duration) and power. Meso/micro scale combustion has been considered as a potential solution for many small-volumes and energy demanding systems, such as power supplies for portable device. In this study the structure of turbulent diffusion flames in a meso scale combustor with different oxygen concentration has been investigated using a new design of vortex combustor. Methane gas was used as a fuel. Numerical investigations have been performed on the temperature distribution, swirl number, heat loss, and emitter efficiency in vortex combustion. The results have been obtained for various O2 concentrations in the air as oxidizer. The results shows that thermal flame behaves depend strongly on the oxygen content in the oxidizer. When the oxygen concentration increases from 15% to 30%, the flame temperature of the meso-combustion rises in all cases. Emitter efficiency is very high in the meso-combustor with high O2 concentration in oxidizer

Preliminary analysis on matric suction for barren soil

Most research conducted on slope failures can broadly be attributed to the convergence of three factors, i.e. rainfall, steepness of slope, and soil geological profile. The mechanism of the failures is mainly due to the loss of matric suction of soils by rainwater. When rainwater infiltrates into the slopes, it will start to saturate the soil, i.e., reduce the matric suction. A good understanding of landslide mechanisms and the characteristics of unsaturated soil and rock in tropical areas is crucial in landslide hazard formulation. Most of the slope failures in unsaturated tropical residual soil in Malaysia are mainly due to infiltration, especially during intense and prolonged rainfall, which reduces the soil matric suction and hence decreases the stability of the slope. Therefore, the aim of this research is to determine the matric suction for barren soil and to model an unsaturated slope with natural rainfall to evaluate the effects of matric suction on rainfall intensity. A field test was carried out using the Watermark Soil Moisture Sensor to determine the matric suction. The sensor was connected to a program called SpecWare 9 Basic which also used Data Logging Rain gauge Watermark 1120 to measure the intensity and duration of rainfall. This study was conducted at the Research Centre for Soft Soil which is a new Research and Development (R & D) initiative by Universiti Tun Hussein Onn Malaysia, Parit Raja. Field observation showed that the highest daily suction was recorded during noon while the lowest suction was obtained at night and early morning. The highest matric suction for loose condition was 31.0 kPa while the highest matric suction for compacted condition was 32.4 kPa. The results implied that the field suction variation was not only governed by the rainfall, but also the cyclic evaporation process. The findings clearly indicated that the changes in soil suction distribution patterns occurred due to different weather conditions

Beam scanning folded reflectarray antenna with shifted waveguide positions

International audienc

Beam scanning folded reflectarray antenna with shifted waveguide positions

International audienc

Seawater intrusion mapping using electrical resistivity imaging (ERI) at Malaysian coastal area

Natural process of seawater intrusion occurs in many coastal areas all around the world. Previous experiences have recorded that the phenomena will cause a problem to the freshwater aquifer due to its salinity contamination. Conventional approach on saltwater detection also suffers from efficiency in term of cost, time and data coverage. Hence, this study has introduced an electrical resistivity imaging (ERI) for saltwater intrusion mapping based on time lapse condition. Data acquisition and processing of ERI was performed using ABEM SAS 4000 and RES2DINV software. It was found that resistivity value was varied during different water tide due to migration of saltwater and freshwater within the aquifer. Saltwater, brackish water and freshwater was detected based on resistivity values of 0.1 – 5 Ωm, 5 – 15 Ωm and 50 – 100 Ωm respectively. This study was successfully demonstrated the applicable of ERI in saltwater intrusion mapping thus able to contribute to the sustainable future decision planning and development at the study area

Pulse detonation engine research development at high speed reacting flow laboratory-hiref, Universiti Teknologi Malaysia

The Pulse detonation Engine (PDE) research program has been started at High Speed Reacting Flow Laboratory (HiREF), Universiti Teknologi Malaysia (UTM) since 2005. The studies began with a single pulse detonation study for detailed investigation of detonation characteristics of various fuels and followed by development of repetitive PDE engine, performance study and augmentation of thrust using various types of ejectors. This paper summarizes the laboratory facilities, research activities conducted and the output from all of the related research programs