Mountain-Shaped Coupler for Ultra Wideband Applications

This paper demonstrates a novel mountain-shaped design for a compact 3-dB coupler operating at ultra-wideband (UWB) frequencies from 3.1GHz to 10.6 GHz. The proposed design was accomplished using multilayer technology in which the structure is formed by three layers of conductors interleaved by a layer of substrate between each conductor layer. Simulation was carried out using CST Microwave Studio; the result was then compared with results from rectangular and star-shaped couplers that implemented the same technique. The results obtained show that the proposed new coupler has better performance compared to both rectangular and star-shaped coupler designs in terms of return loss, isolation, and phase difference. The coupler was fabricated and measured; the measurement results satisfactorily agree with the simulation results

Compact wideband broadside-coupled microstrip-slot bandpass filter for communication applications

This paper proposes a compact size design of wideband bandpass filter (BPF). The broad-side coupling microstrip-slot technique is used to accomplish a good passband response with very low insertion loss across a wideband frequency range. The BPF that is designed using Rogers RO4003C substrate shows a good performance with the respective maximum reflection coefficient and insertion loss of -10 dB and 1.2 dB between 0.92 GHz and 5 GHz. This type of BPF filter is useful in any communication applications

Characterization of cocoa butter equivalent from formulated hard palm oil mid-fraction and canola oil blend

A search for an alternative to cocoa butter (CB) has increased due to premium price, uncertainty in supply and variability in quality problems. The study to find cocoa butter equivalent (CBE) as an alternative to CB from available and high nutritional oils or fats was carried out using enzymatic interesterification method. The objective of this study was to characterize the CBE obtained from hard palm oil mid-fraction (PMF) and canola oil blend using immobilized lipase from Rhizomucor miehei. The experiment was performed at hard PMF concentration of 50%, lipase load of 7.2% (based on weight of substrate) and reaction time of 2 hours. The characteristics observed were fatty acid profiles, triacylglycerol (TAG) composition, slip melting point (SMP) and solid fat content (SFC). CBE obtained exhibit higher percentage of linoleic acid (omega 6, 7.98%) and linolenic acid (omega 3, 2.47%) than CB (3.40% of linoleic acid) due to the addition of canola oil. TAG composition was 28.65% of palmitic-oleic-palmitic (POP), 19.52% of palmitic-oleic-stearic (POS), and 3.57% of stearic-oleic-stearic (SOS). SMP value of CBE (46.25°C) was higher than CB (32-35°C). The SFC value of CBE was different to CB. It was due to high amount of POP TAG, free fatty acid (FFA) or saturated saturated saturated (StStSt) TAGs in CBE produced and also lack amount of TAGs which has oleic acid at sn 2 position

Effect of Interphase Region and Neighboring Particles on Electric Field Intensity within Nanocomposite Systems

Recent works show that the presence of the interphase surrounding nanoparticles can improve the dielectric properties of nanocomposites. Also, neighboring particles in the nanocomposites affect the electric field distribution. Therefore, the objective of this paper to model and analyze the effect of onedimensional (1D) nanofillers towards the electric field distribution when the interphase and neighboring are taken into account inside the nanocomposite system. By using Finite Element Method Magnetics (FEMM) 4.2 software, a model of nanocomposites system consists of polymer matrix, nanoparticle filler with interphase and neighboring particles is modeled under the electrostatic problem module. Electric field intensity is observed with different distance between adjacent nanoparticles and interphase region permittivity values. The result obtained show that the presence of the interphase with various permittivity value will result in distorted electric field intensity surrounding a nanoparticle. Furthermore, the electric field intensity also affected when adjacent nanoparticles displaced between each other within nanocomposites

Investigation of Unequal Planar Wireless Electricity Device for Efficient Wireless Power Transfer

This article focuses on the design and investigation of a pair of unequally sized wireless electricity (Witricity) devices that are equipped with integrated planar coil strips. The proposed pair of devices consists of two different square-shaped resonator sizes of 120 mm × 120 mm and 80 mm × 80 mm, acting as a transmitter and receiver, respectively. The devices are designed, simulated and optimized using the CST Microwave Studio software prior to being fabricated and verified using a vector network analyzer (VNA). The surface current results of the coupled devices indicate a good current density at 10 mm to 30 mm distance range. This good current density demonstrates that the coupled devices’ surface has more electric current per unit area, which leads to a good performance up to 30 mm range. Hence, the results also reveal good coupling efficiency between the coupled devices, which is approximately 54.5% at up to a 30 mm distance, with both devices axially aligned. In addition, a coupling efficiency of 50% is achieved when a maximum lateral misalignment (LM) of 10 mm, and a varied angular misalignment (AM) from 0° to 40° are implemented to the proposed device

Distribution Voltage in DC Micro-grid System based Solar PV Topologies Configuration in Sarawak, Malaysia

In the past few decade, longhouse communities in the rural area of Sarawak has been experienced the limitation of electricity supplies. Due to geographic of Sarawak, supply electricity to these rural areas from utility grid through transmission lines also will only results in many losses, the initiation of utilize solar as prime sources is favourable solution. The implementation of DC microgrid system for this area will achieved, as the solar PV system is a DC source to generate electrical supply for appliances in longhouse communities. However, the tropical climate and geographical in Sarawak such as the inconsistent solar radiation, changing temperatures, high humidity and heavy rainfall will be the main restrain to implement solar DC microgrid system. Thus, this paper proposes a comprehensive study about the voltage distribution of DC microgrid configuration in order to investigate system the reliability and efficiency. The configuration of DC micro-grid model has been designed using MATLAB Simulink and an experimental presenting the Simulink also has been developed for validation purposes. The obtained simulation and experimental results confirm that the proposed configuration of the ring system with multiple-sources is more reliable and efficient than radial system with multiple-source configuration in terms of DC voltage distribution at different buses. Thus, the proposed configuration is more reliable according to voltage distribution at each buses

Biopolymeric encapsulation of probiotics for improved release properties in the gastrointestinal digestion system

Encapsulation of probiotics in the biopolymeric system is an excellent technique to enhance the protective effect, prolong the shelf life and deliver the probiotics in the human gastrointestinal tract at a specific time. Probiotics are usually loaded in a biopolymeric system or the food itself as a natural carrier for food applications. Probiotics are well-known for a healthy intestinal tract and digestibility of nutrients. The fate and viability of these bacteria in the digestion system are explored through in vitro evaluations. Probiotics encapsulated with natural biopolymers such as alginate, chitosan, gelatine, whey protein are found to improve their release properties in either emulsion or hydrogel system. This review emphasized on the release properties of encapsulated probiotics loaded with biopolymers using different dispersion methods including emulsification, suspension, extrusion, and drying. Biodegradable polymers or the food itself could be a potential protective agent and promote the controlled-release properties of probiotics

UV Induced Mutagenesis Elevates the Production of Laccase in Enterobacter cloacae

442-448The increasing commercial significance of microbial laccase in various fields compels the supply of enzymes in large quantities at an affordable price. Laccase has been produced by a wide variety of wild cultures of bacteria and fungi, the high yielding strains are always desired to meet the increasing demand of laccase. Although various approaches have been proposed for improving the yield of laccase, UV mutagenesis is known as the best method of improving the strains for better yield of microbial metabolites. However, the reports on the use of UV light in strain improvement for laccase production by the use of Enterobacter sp. are scarce and need to be explored fully. For this purpose present study was aimed to improve the laccase production in Enterobacter cloacae through UV mutagenesis. We report enhanced production of laccase in a high yielding strain of E. cloacae isolated from the soap industry waste. UV mutagenesis of a wild strain of E. cloacae resulted in 3.09 folds further improvement in the production. Optimum laccase synthesis was reported at 26 h, of incubation at 30ºC under neutral pH (7.0) conditions. This high yielding mutant strain will have great industrial significance for laccase production