Articles

This research work is about the propagation of electromagnetic waves on coaxial cables such that its resistive losses are minimized, and signal quality is improved. The resistive loss of a coaxial cable is caused by several things; impedance of the conductor, and the type of dielectric material used and the skin effect and causes the signal to be attenuated. In this research, various comparison was made on different coaxial cables in other to test their resistivity per length of the conductor and measure the losses per meter of the coaxial cables. The various properties of the conductor, the impedance, capacitance, and the velocity of propagations was taken into consideration. Measurements were carried out to derive our data, and MATLAB was used in analyzing the results and the behaviour of the LMR series, RG8, RG6A, Davis RF, and CQ110 coaxial cables. Based on the findings, it is concluded that for a better and improved signal quality and to reduce resistive losses in coaxial cables, the characteristic impedance of the cable should be 80 ohms as this will reduce the coaxial cable resistive losses.

<i>Musanga cecrepoides</i> is an interesting wood species due to its diverse utility ranging from medicine, shade, ornaments etc. Research has been conducted on other properties of this wood species with little information about its acoustic properties. Thus, the evaluation of its acoustic properties is pertinent so as to increase the information bank of its properties. This study assessed the acoustic properties of <i>Musanga cecrepoides</i> wood obtained from selected states and locations in the Niger Delta region of Nigerian viz a vis, Rivers, Bayelsa and Delta States. Test samples were collected from different stem positions axially (top, middle, base) and radially (inner and outer) and analyzed using the statistical software package IBM SPSS Statistics, Version 23 (IBM Corporation, New York, USA). Analysis of variance (ANOVA) was performed at 5% level of significance to determine whether the assessed acoustic properties were significantly different among different stem positions. Results showed that sound frequency (f) at top wood (3061.71 Hz) and outer wood (3096.06 Hz) had significantly higher resonance frequency compared with the bottom wood (2768.01 Hz) and inner wood (2349.54 Hz) respectively. The mean sound velocity (v) at both the axial (2069.59 m/s) and radial (1905.96 m/s) stem positions fell short of the estimated mean v of other wood species when compared. However, such result is suitable for other acoustic purposes with moderate sound velocity. The sound radiation coefficient (R) values were highest at the bottom (4.18) axially and outer (4.13) radially when compared to other stem orientations of the wood. Whereas axially at the top (1561815.86 Kg/(m<SUP>2</SUP>s)) and radially at the outer position (1558292.53 Kg/(m<SUP>2</SUP>s) Sound Impedance (z) was highest when compared with other stem positions of the <i>Musanga cecrepoides</i> wood.