A novel Multi-permittivity Cylindrical Dielectric Resonator Antenna for Wideband Applications

In this paper, a novel multi-permittivity cylindrical dielectric resonator antenna for wideband application is presented. The multi-permittivity cylinder is formed by combining two different permittivity material sectors in such a way that each sector (with constant permittivity) is 90 degree apart. A direct microstrip line coupling terminated with T-stub at the open end is used to excite the multi-permittivity cylindrical dielectric resonator. The angular position of the multi sector dielectric resonator with respect to the longitudinal axis of the microstrip line and length of the additional strip at the open end of the feeding circuit is key parameters for wideband operation of the antenna. By optimizing all parameters of the proposed antenna, wideband impedance bandwidth of 56% (12.1 GHz - 21.65 GHz) is achieved. The average gain of the antenna throughout the bandwidth is 5.9 dB with good radiation properties in both E-plane and H-plane. A well matched simulation and experimental results show that the antenna is suitable for wideband applications

Pulsed Laser Heating of a Thermoelastic Medium with Two-temperature under Three-phase-lag Model

In this paper, the problem of the generalized thermoelastic medium for three different theories under the effect of a laser pulse and two-temperature is investigated. The Lord–Shulman (L-S), Green-Naghdi of type III (G-N III) and three-phase-lag (3PHL) theories are discussed with two-temperature. The normal mode analysis is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically and the thermal force was applied. Comparisons are made with the results predicted by (3PHL), (G-N III) and (L-S) in the presence and absence of two-temperature. The boundary plane surface is heated by a non-Gaussian laser beam

Influence of biofertilizer on growth improvement of aerobic rice genotypes

Biofertilizers have emerged as a potential environment friendly inputs that are supplemented for proper plant growth.Two field experiments were conductedat University Putra Malaysia (UPM), Selangor, Malaysia during 1st season (Mayto September 2015) and 2nd season (September to December 2015)to evaluate the performance of aerobic rice genotypes under different combinations of bioandchemical fertilizer. The experiment consisted of five (5)biofertilizer combinations (chemical fertilizer recommended rate (CFRR) (150 N; 60 P2O5;60 K2O kg ha-1) 100%,biofertilizer 1 ton+ 75%CFRR,biofertilizer 2 tons + 50%CFRR,biofertilizer 3tons+ 25%CFRR,and biofertilizer 4 tons)and three aerobic rice genotypes (MRIA1, MR219-4 and MR219-9)laid out in a split-plot in randomized complete block design(RCBD) with 3 replicates.Results revealed that application of biofertilizer 1 ton + 75%CFRR produced the highest plant height (102.65 cm) and an umberof tillers (20.38) in the 2nd season, the highest grain yield (4.30 t ha-1) than theother biofertilizer treatments in the 1st season. MR219-4 produced the highest number of tillers, leaf area and leaf photosynthesis rate in both seasons,grain yield (5.02 t ha-1) in 1st season while MR219-9 produced the highestcropbiomass (52.76 g hill-1) and crop growth rate (8.00 g hill-1week-1) at 12 WAS,grain yield (3.86 tha-1) than the other genotypes in the 2nd season.The trend in these results indicated that biofertilizer tend to be more effective with limited chemical fertilizer in the 1st season of low rainfall.These results concluded that 1 ton biofertilizer + 75% CFRR andMR219-4enhancesrice growth and grain yield in aerobic condition

A Numerical Algorithm for Solving Stiff Ordinary Differential Equations

An advanced method using block backward differentiation formula (BBDF) is introduced with efficient strategy in choosing the step size and order of the method. Variable step and variable order block backward differentiation formula (VSVO-BBDF) approach is applied throughout the numerical computation.The stability regions of the VSVO-BBDFmethod are investigated and presented in distinct graphs.The improved performances in terms of accuracy and computation time are presented in the numerical results with different sets of test problems. Comparisons are made between the proposed method and MATLAB’s suite of ordinary differential equations (ODEs) solvers, namely, ode15s and ode23s

Mechanical Properties of Epoxy Composites Containing Carbon Black and Graphene

Epoxy composite has been widely used in various industrial applications due to its high strength. Nevertheless, its high strength causes it to fracture easily. Fillers are often added to improve its fracture toughness and other properties. In this work, epoxy composites containing carbon black (CB) and graphene have been synthesized to assess their mechanical properties. Series of analysis have been performed on composites containing single filler (CB or graphene) of various loadings to evaluate the values of Young’s Modulus, yield strength, and KIC. The results demonstrate an improvement in Young’s Modulus, yield strength, and KIC values by adding different carbon fillers, compared to neat epoxy. Based on these results, composites containing dual fillers are fabricated to understand the resultant synergistic effects. The hy-brid fillers show an increment in both fracture toughness and yield strength test for the epoxy composite with an optimum improvement at (3.0 wt.% CB + 0.1 wt.% Graphene) loading which is an increase of 256% in the values of Young’s Modulus, compared to neat epoxy. The addition of carbon fillers enhances the mechanical properties of epoxy composites, with dual fillers demonstrate the highest improve-ment, which could be due to the improvement in the dispersion degree

SINGLE STAGE RF AMPLIFIER AT 5.8GHZ ISM BAND WITH IEEE 802.11a STANDARD

This paper describes the circuit design and measurement of a single stage RF amplifier for 5.8 GHz-band with IEEE 802.11a standards for WLAN applications.The circuit was simulated using Ansoft Designer where a 14dB of gain; input and output return loss less than -10dB were observed. The GaAs Hetrojunction FET (HFET), capacitors and resistors are combined with the microstrip line pattern by silver epoxy. A 1dB output power compression point (P1dB) of 17dBm and 14.56dB of gain when -1dBm power injected under 6V and ½ Idss biasing are measured

5.75 GHz Microstrip Bandpass Filter for ISM Band

This paper presents on 5.75 GHz bandpass filter based on IEEE802.11a standard for wireless LAN application. The development of bandpass filter includes calculation, simulation, testing and measurement of the filter parameters process has been presented. Simulation software for this project used Ansoft Designer software. The filter operates at center frequency of 5.75 GHz with 100 MHz bandwidth and insertion loss below 10 dB. The bandpass filter contributes to the application of direct conversion front-end receiver for WLAN application at 5.8 GHz frequency

Carbonized rice husk and cocopeat as alternative media bed for aquaponic system

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA

Simulation Of Cascading LNA And RF Amplifier For Front-End Direct-Conversion Receiver At 5.8 GHz

In this paper, a simulation of cascaded LNA and RF amplifier for front-end direct conversion receiver at 5.8-GHz frequency band is presented. By using direct conversion architecture, the image rejection performance is improved, lower complexity and the component is reduced. The cascading LNA and RF amplifier has 27 dB gain and 2.17 dB noise figure. The LNA and RF amplifier is simulated using Ansoft Designer software and fabricated with Duroid 5880 as the microstrip material