The Effect of Chamfering Structure towards the Design of Open Loop Resonator Bandpass Filter for Microwave Applications

Filter is the most essential components in the transceiver system. It is used to accept and reject any unwanted frequencies that falls out of the bands. Recently, the design of bandpass filter (BPF) has been a great challenges for RF designer. Although many researches have designed filter in the unlicensed frequency but most of the filter suffered from high insertion loss, inadequate selectivity and wider bandwidth. Therefore, this project design an Open-Loop Resonator Bandpass Filter (OLRBPF) to produce a low loss filter to operate at 2.4 GHz frequency. In order to overcome the high insertion loss, chamfered bend is introduced and implemented at the OLRBPF’s structure. This will reduce the radiation loss produced and enhanced the coupling between both resonators of the filter. The results show that the proposed OLRBPF produce better insertion loss compare to conventional filter

Effects of different organic additives on in vitro shoot regeneration of Celosia sp

Nowadays, many researches were conducted in minimizing tissue culture technology due to the overhead of cost needed. The purpose of this study was to investigate the effects of using five kinds of organic additives at four level concentrations responsive to the number of shoots produced for eight weeks in culture. Stem segment explants of Celosia sp. were cultured on MS medium that have been supplemented with different kinds of extract juice that serve as organic additives which are mature coconut, young coconut, papaya, banana and tomato at 20, 30, 50 and 70 ml L -1. The numbers of shoot on each explant were recorded and the mean of ten replicates explants were calculated. Among the media used, young coconut water at 70 ml L -1 induced the highest shoot regeneration (14.21 ±8.26), followed by mature coconut water at 50 ml L -1 (13.14±10.33). Banana and tomato juice promote highest shoot regeneration of stem segments at 50 ml L -1 that produced 9.57±4.68 and 9.28±5.82 shoots per explants, respectively. While the lowest concentration which at 20 ml L -1 of papaya juice showed highest shoot regeneration (10.50±3.45) produced among the three other concentration tested. Statistical results showed that there were significant differences interactions effects (p<0.05) in terms of number of shoot regenerated between the types of extracts juices determined by ANOVA test. Comparing number of shoots regenerated that were cultured in control media, it showed higher than all of experimental medium composition. There were no big different in cost required in preparation of control media and the experimental media. Applications of five kinds of local fruit in tissue culture media should be considered since it responsive in shoot regeneration. © 2011 Asian Network for Scientific Information

Potential of alternative gelling agents in media for the in vitro micro-propagation of Celosia sp

Plant tissue culture techniques often require optimization for cost reducing by substitute the culture medium with kitchen necessity. This study conducted to investigate various commercial starches namely; cassava flour, rice flour, corn flour and potato starch to be alternatives gelling agents in culture medium preparation. MS basal medium was prepared without plant regulator supplemented with different combinations of alternative gelling agent with Oxoid technical agar. After 8 weeks in culture, the highest of shoot regeneration were obtained on cultured in MS medium containing 40 g L -1 corn flour (10.2Q±9.17), 60 g L -1 cassava flour (40.0Q±6.73), 40 g L 1 rice flour (16:00±12.45) and the combination of 40 g L 1 potato starch plus 2 g L 1 agar (27.20±8.59). ANOVA test shows there were significant differences interactions effects (p<0.05) in terms of number of shoot regenerated between the gelling agents used (40, 50 and 100 g L -1) in combination of agar. On the other hand, no significant different interaction effects at combination of 60 g L -1 gelling agent. The results showed that the combination of alternative gelling agent with agar or gelling agent alone successfully regenerated shoots from the stem segment explants of Celosia sp. No physiological effects were observed on shoots regeneration on Celosia sp. Applications of these alternative gelling agents in tissue culture media should be considered to achieve the optimum benefit for in vitro shoots regeneration. These options are cheaper than control one and could be used for low cost alternatives. © 2011 Asian Network for Scientific Information

Fabricated germanium-doped optical fibres for computed tomography dosimetry: Glow curve characteristics

Fabricated germanium (Ge)-doped optical fibre glow curve characteristics are investigated with respect to computed tomography (CT) dosimetry. 2.3 mol% and 6 mol% Ge-dopant concentration preforms have been used to produce flat and cylindrical fibres (FF and CF) of various size and diameter. The fibres are irradiated to doses of 20, 30 and 40 mGy for each of the beam qualities RQT 8 (100 kV), RQT 9 (120 kV) and RQT 10 (150 kV). The thermoluminescence (TL) kinematic parameters studied are maximum temperature (Tmax), activation energy (Ea) and peak integral (PI). The glow curve formations are reconstructed from the Windows®–based radiation evaluation and management system (WinREMS), deconvoluted using glow curve deconvolution (CGCD) analysis software. The structures of the glow curves are broad single or double-peaked, occurring at relatively high glow peak temperatures, TL response increases with radiation dose and peak height decreases with increasing energy, showing clear photoelectric dependence. The deconvoluted glow curves for all fibres are seen to consist of five individual glow peaks, P1 to P5, P1 being dominant in all cases other than for 6 mol% Ge-FF for which P3 is dominant due to the formation of a double-peaked glow curve. Tmax increases from P1 to P5 for all fibres, throughout the energy range used. P1 and P3 (6 mol% Ge-FF) have the lowest Ea, while P4 shows the greatest Ea for all fibres. The results indicate that electrons in P1 and P3 (6 mol% Ge-FF) are occupied at low energy traps while for P4, the electrons are trapped at a deeper energy level. The lowest PI value, indicative of the least number of electrons, is shown to be that of the deeper trap P4 for all energies investigated. This study provides support for the use of 6 mol% and 2.3 mol% preform fibres for CT dosimetry, each with similar kinetic parameters