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Discrete Evolutionary Programming for Network Splitting Strategy: Different Mutation Technique
No full textNetwork splitting is performed to prevent the power system network from blackout event during severe cascading failures. This action will split the power system network into few islands by disconnecting the proper transmission lines. It is very important to select the optimal splitting solution (transmission lines to be removed) to ensure that the implementation of network splitting does not cause the system to worsen. Therefore, this paper investigates two different mutation techniques; single-level and three-level mutation, utilized in Discrete Evolutionary Programming (DEP) optimization to find the optimal splitting solution following a critical line outage. Initial cutsets based heuristic technique is employed to help the convergence of the DEP optimization with minimal power flow disruptions as its fitness function. The techniques are validated using the IEEE 30 and IEEE 118-bus system. The results show that three-level mutation technique produces better optimal splitting solution as compared to single mutation technique
Preparation and Characterization of Nickel ferrite Nanoparticles via Co-precipitation Method
No full textNickel ferrite (NiFe2O4) nanoparticles were synthesized using co-precipitation method. The X-ray diffraction (XRD) pattern was used to determine the structure of NiFe2O4 nanoparticles. The presence of NiFe2O4 nanoparticles was confirmed by the FT-IR spectrum. The details of the surface morphology of NiFe2O4 nanoparticles were obtained by Scanning Electron Microscopic analysis. The particle size of the NiFe2O4 nanoparticles could be determined by means of Transmission Electron Microscopy. This work aimed at the investigation of the dielectric properties such as the dielectric loss and the dielectric constant of NiFe2O4 nanoparticles at varied frequencies and temperatures. In addition, the magnetic properties of the NiFe2O4 nanoparticles were studied
Literature Review on Green Cost Premium of Sustainable Building Construction
No full textDespite evidence that sustainable construction practice has numerous environmental, economy and societal benefits, many construction practitioners have failed to support sustainable construction practice due to perceive higher initial cost known as 'green cost premium' when compared to traditional construction practice. Hence, the factors of green cost premium that are commonly cited as a crucial barrier toward sustainable construction practice must be investigated. Based on the analysis of the existing literature (e.g.: conference paper, journal article), there are 27 factors, that classified into seven elements, that contribute to the cost differential. However, few studies have been conducted on green cost premium in developing countries. Therefore, this study attempts to fill this gap and is expected to contribute to the discussion on green cost premium to improve sustainable construction implementation
The past, present and future of policy modeling
No full textWe evaluate the past, present, and future of policy modeling from both qualitative and quantitative perspectives. We do this through an extensive review and analysis of papers published in the Journal of Policy Modeling between 1978 and 2018. Over the years the focus of the policy modeling literature (and the Journal) changed. The changes were in research topics, approaches, techniques, theories, methods, and analytical tools as required for the rigorous analysis of complex and dynamic economic phenomena in policy modeling
Optimization of equitable irrigation water delivery for a large-scale rice irrigation scheme
No full textEquitable water allocation is essential in an irrigation scheme for obtaining potential crop yields from the entire scheme, especially when water supply is inadequate. An optimization model achieved this goal by coupling an optimal water allocation model with available water supply and irrigation water demand for a river-fed rice irrigation system in Malaysia. This model consists of a paddy field water balance module and an optimization module. The outputs from the module are daily irrigation demand and surface runoff, if there is any. The optimization module consists of an objective function, which minimizes water shortage across the scheme area while maintaining equity in water allocation. This model performs optimization subject to several system constraints, and the decision variable of the model is daily releases or supply to the tertiary canals. Performance of this model remained unaffected under different water supply conditions, and the optimization model reliably examined the effects of alternate water allocation and management rules with field information. It improves efficiency and equity in water allocation with respect to crop growth stages and water shortages rather than simply cutting irrigation supply on a proportional basis to overcome water shortages
Investigation of VTP:PC71BM organic composite as highly responsive organic photodetector
No full textIn this work, we report the use of vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis(dimethylamino)-29H,31H-phthalocyanine (VTP) in the fabrication of organic photodetector that aimed to be more responsive in the lower region of visible light. The thin active layer of the photodetector has been developed from the vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis(dimethylamino)-29H,31H-phthalocyanine (VTP) [6,6]:-phenyl C71 butyric acid methyl ester (PC71BM) blend solution. The combination of VTP and PC71BM has significantly enhanced the absorption of visible light especially below 650 nm for the ITO/PEDOT:PSS/VTP:PC71BM/Al photodetector. The detector showed good photocurrent-illumination linearity, fast response-recovery time and high consistency towards the rapid change of light intensities. It is found that the detector exhibits a good photoresponsivity of 2.30 × 10-1 A/W
Enhancement of confined femto-ablation at SiO2/Si interface by embedded metallic nanoparticles
No full textInfluence of doping an SiO 2 /Si interface with metallic nanoparticles (MNPs) on confined laser ablation and resulting structural properties of the crystalline silicon (c-Si) substrate was investigated by irradiating the composed interface with a single, tightly focused femtosecond laser pulse. Confinement ablation regime was enforced by a 10 μm–thick SiO 2 layer capping the c-Si substrate. A mixture of gold (Au) and silver (Ag) nanoparticles was placed at the interface to take advantage of the presumed plasmon-induced enhancement of the incident field strength in a broad spectral range. The nanoplasmonic effect is visualised by numerical simulations utilising the mathematical apparatus of the finite-difference time-domain (FDTD) method. The structural transformations at the site of the laser-induced damage were investigated dominantly by the scanning (SEM) and high-resolution transmission (HRTEM) electron microscopes. A comparative analysis of the irradiation effects in the targets containing different combinations of the interface composing elements revealed clear and strong influence of the confinement and doping on the irradiation result. Character of the observed transformations (among others the crystal twinning) suggests dominant role of increased pressure in the process through the locally generated shock waves
Titanium dioxide doped fiber as a new saturable absorber for generating mode-locked erbium doped fiber laser
No full textThis work reports on the use titanium dioxide doped fiber (TiO2DF) as a passive saturable absorber (SA) in generating stable and self-starting mode-locked pulse laser in Erbium doped fiber laser (EDFL) ring cavity. The TiO2DF SA is a self-made fiber with 20 cm in length. It has a core diameter of 45 μm, the numerical aperture (NA) of 0.21, core composition of Silica-Titanium (Si-Ti) and cladding composition of Silica Oxides (SiO2). The TiO2DF SA has a wide-band linear absorption profile which also covers the mode-locked laser operating wavelength of 1553 nm. The TiO2DF serves as a great SA due to the presence of anatase crystalline form of TiO2 which provide saturable optical losses in the laser cavity. Results show that reliable mode-locked pulse is observed as the pump power raises from 106 mW to 142 mW. Within this range of pump power, a nearly constant repetition rate within the range of 0.984 MHz to 0.990 MHz is obtained. The actual pulse width seen from the autocorrelator is about 9.74 ps. Both, the maximum peak power of 878 mW and the maximum pulse energy of 8.56 nJ are calculated at the maximum pump power (142 mW). The fundamental frequency of the EDFL mode-locked pulse laser has a signal to noise ratio (SNR) of 54 dB. Our demonstration shows that the TiO2DF-SA is reliable and quite promising in generating EDFL mode-locked pulse laser
Nesting biology of Black-shouldered Kite ( Elanus caeruleus ) in oil palm landscape in Carey Island, Peninsular Malaysia
No full textBlack-shouldered Kite (Elanus caeruleus) is a well-known raptor that inhabits open areas such as oil palm plantation or paddy field. To determine preferable habitat and nesting site of Black-shouldered Kite in oil palm landscape, we conducted a study on Black-shouldered Kite's nesting biology in Carey Island, Selangor, Malaysia. We divided the island into six types of habitat and conducted road-side count of Black-shouldered Kite from April 2009 to February 2011. Whenever the Black-shouldered Kite was detected, we thoroughly searched the surrounding area for their nest. In total, we have recorded forty nests. The nests were built on 15 species of trees but most of the trees shared common physical characteristics. Some novice breeders also used oil palm tree as their nesting site. Structure and building materials of nests constructed on oil palm trees were different from nests built on other trees. Of all breeding attempts, only four nests which were located in residential area adjacent to young oil palm habitat were successful. Among important characteristics of successful nesting site include taller trees with strong branches and good leaf coverage. These trees not only protect nests from predator detection (except from other predatory birds) and physical environment but also facilitate Black-shouldered Kite's foraging activities by providing good vantage point
Characterization of biogenic hydroxyapatite derived from animal bones for biomedical applications
No full textIn this work, the viability of producing biogenic hydroxyapatite from bio-waste animal bones, namely bovine (cow), caprine (goat) and galline (chicken), through a heat treatment process has been investigated. The animal bones were locally sourced, cleaned to remove collagen and subsequently heat treated in air atmosphere at different temperatures ranging from 600 °C to 1000 °C. From the range of sintering temperatures investigated, it was found that hydroxyapatite derived from bovine bone showed good thermal stability while those produced from caprine and galline bones exhibited phase instability with traces of tri-calcium phosphate (TCP) being detected after heat treatment beyond 700 °C. The porous nature of the bone samples can be observed from the microstructures obtained and supported by low relative density. Heating the bovine and caprine bones at selected temperatures yielded porous HA body, having hardness values that are comparable with human cortical bone. However, the sintered galline bone sample showed higher porosity levels and low hardness when compared to the other two bone types