Abstract-Rubber tire dust-rice husk is an innovation in improving the design of pyramidal microwave absorbers to be used in radio frequency (RF) anechoic chambers. An RF anechoic chamber is a shielded room covered with absorbers to eliminate unwanted reflection signals. To design the pyramidal microwave absorber, rice husk will be added to rubber tire dust since the study shows that both have high percentages of carbon. This innovative material combination will be investigated to determine the best reflectivity or reflection loss performance of pyramidal microwave absorbers. Carbon is the most important element that must be in the absorber in order to help the absorption of unwanted microwave signals. In the commercial

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This paper presents the development of a PC-based microwave five-port reflectometer for the determination of moisture content in oil palm fruits. The reflectometer was designed to measure both the magnitude and phase of the reflection coefficient of any passive microwave device. The stand-alone reflectometer consists of a PC, a microwave source, diode detectors and an analog to digital converter. All the measurement and data acquisition were done using Agilent VEE graphical programming software. The relectometer can be used with any reflection based microwave sensor. In this work, the application of the reflectometer as a useful instrument to determine the moisture content in oil palm fruits using monopole and coaxial sensors was demonstrated. Calibration equations between reflection coefficients and moisture content have been established for both sensors. The equation based on phase measurement of monopole sensor was found to be accurate within 5% in predicting moisture content in the fruits when compared to the conventional oven drying method.

Abstract-A change in the relative proportions of a mixture of rubber tire dust and rice husks will cause a change in the mixture's electrical permittivity and its ability to absorb electromagnetic energy. An openended coaxial probe was used in conjunction with three dielectric mixture equations (the Kraszewski equation, the Landau equation and the Lichtenecker equation) to obtain the dielectric properties of a mixture of rubber tire dust and rice husks (RTDRH) over the frequency range of 7 GHz to 13 GHz. Lichtenecker's equation for dielectrics proved to be a useful practical formulation for determining the effective permittivity of homogeneous dielectric mixtures. The effectiveness of these dielectric mixture equations in determining the effective permittivity of RTDRH was investigated in this study. A newly developed mixture equation was derived based on these dielectric

Abstract. The oil palm empty fruit bunch (OPEFB) natural fibres were comprehensively reviewed to assess their potential as reinforcing materials in polymer composites for energy absorption during low-velocity impact. The typical oil palm wastes include trunks, fronds, kernel shells, and empty fruit bunches. This has a tendency to burden the industry players with disposal difficulties and escalates the operating cost. Thus, there are several initiatives have been employed to convert these wastes into value added products. The objective of this study is to review the potential of oil palm empty fruit bunch (OPEFB) as natural fibre polymer composite reinforcement to absorb the energy during low-velocity impact as another option for value added products. Initially, this paper reviewed the local oil palm waste issues. Previous research works on OPEFB polymer composite, and their mechanical characterization is appraised. Their potential for energy absorption in low-velocity impact application was also elaborated. The review suggests high potential applications of OPEFB as reinforcing materials in composite structures. Furthermore, it is wisely to utilize the oil palm biomass waste into a beneficial composite, hence, promotes the green environment.

Abstract-An electromagnetic interference (EMI) shielding material based on the composite of BaFe 12 O 19 , polyaniline (PANI) and multi-walled carbon nanotube (MWCNT) was proposed. The constituents of the composite were brought together through mechanical mixing and the in-situ polymerization of aniline on the BaFe 12 O 19 and MWCNT surfaces. A series of composite with different MWCNT wt% loadings (0, 5, 10, 15, 20 and 25wt%) was prepared, and its effect on the EMI shielding performance was investigated. X-ray diffraction analysis was performed on all synthesized composites to confirm the phase formations. FESEM micrographs reveal the PANI particle formation on both BaFe 12 O 19 and MWCNT surfaces. Electromagnetic measurements were done by using a rectangular waveguide connected to a network analyser to obtain the permeability, μ r , permittivity, ε r , and shielding effectiveness (SE A and SE R ). The increase in the MWCNT loading results in the enhancement of the composite's shielding performance to a certain limit. Optimum EMI shielding performance is shown by sample PBM4 (20wt% MWCNT) with SE R and SE A values of 5.14 dB at 8.2 GHz and 36.41 dB at 12.4 GHz, respectively. The influence of different MWCNT loadings (0, 5, 10, 15, 20 and 25wt%) on the EMI shielding performance of a composite consisting of BaFe 12 O 19 , polyaniline (PANI) and multi-walled carbon nanotube (MWCNT) were investigated.

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Abstract-Composites of rice husks and carbon nanotubes (RHCNTs) are an innovation in improving the absorption of microwave signals. Rice husks, which are an agricultural waste material, have been found to possess a significant propensity for absorbing microwave signals. Studies have shown that both rice husks and carbon nanotubes (CNTs) have high percentages of carbon. Thus, in this paper, we present the results of our experimental study in which we varied the ratios of rice husks and CNTs in the composite materials and determined the dielectric properties of the composites and measured their abilities to absorb microwave signals. The experimental microwave