Physics Memoir - Journal of Theoretical & Applied Physics <p>PHYSICS MEMOIR-Journal of Theoretical &amp; Applied Physics (PM-JTAP) is a web-based peer-reviewed international journal published quarterly (March, June, September &amp; December) by Department of Physics, Federal University Lafia. It offers an exciting publication outlet for theoretical and applied physics.</p> en-US (Prof. Muhammad Sanusi Liman) (Dr. Babatunde James Falaye) Sun, 12 Jul 2020 22:03:18 +0000 OJS 60 Stitched Transmission Line for On-Body Communication Systems <p>In this paper we report the use of a stitched transmission line for on body communications. The stitched transmission line was designed as a two wire braided coaxial cable using CST Microwave Studio Suite®. The constructed line is made up of a copper inner conductor surrounded by a polyethylene tubular insulating layer from a stripped RG174 braided coaxial cable. For shielding purpose, the structure is stitched onto a denim material with a conductive thread with the aid of a novel presser foot. To explore its suitability for on-body communications, the stitched transmission line was placed at approximately 5mm from the human body at the left hand side of the chest just below the nipple area and measurements were taken with an Anritsu MS46524A7GHz Vector Network Analyser (VNA) for a frequency range of 0.04 – 4GHz, with measured results demonstrating that the stitched transmission line can be used for on-body communications.</p> I. H. Daniel, N. Kure, M. U. Benedict, S. H. Sarki, A. A. Kassimu Copyright (c) 2020 I. H. Daniel, N. Kure, M. U. Benedict, S. H. Sarki, A. A. Kassimu Sun, 12 Jul 2020 21:59:23 +0000 An Assessment of Rainfall Attributes and Onsets-Cessations Dates Effective for Cropping in Lafia, Nasarawa State, Nigeria <p>Rainfall affects almost all human lives, significantly in diverse fields like agriculture, business, health, transportation and tourism. Amongst the main endeavours engaged by man, agriculture is the main stake for man’s source of livelihood. Most people are not aware of the attributes of rainfall peculiar to their surroundings, as such embarked on agricultural activities through ``try by error" and are faced with challenges due to the unstable nature of weather. Weather does disappoint most people that are into farming because rainfall varies in the study area. This study aimed at assessing Lafia rainfall attributes and the determination of its onset-cessation dates effective for cropping. Eleven years rainfall data of Lafia was collected for the study. The analysis was carried out using Excel tool and Mann Kendall analytical approach with the aid of Xl statistical software in the description of Lafia rainfall attributes. The study reveals a less stability nature of rainfalls at a value greater than 40, and a fluctuating onset dates between April and May with drought and dry spell occurrences in each of the growing seasons were recorded. The study therefore concluded that, there exist a less stable rainfall amount and a highly stable rainfall frequency of occurrences; all these affects food crops production and its output as the average rainfall amount recorded is (1371.2 mm) while the average number of rainy days in the study was (95 days). It is therefore recommended that other researchers should carry out an empirical study on the severity of drought and dry spell in the study area.</p> J. T. Yashim, A. F. Abdussalam, I. I. Abbas Copyright (c) 2020 J. T. Yashim, A. F. Abdussalam, I. I. Abbas Wed, 26 Aug 2020 07:17:31 +0000 Characterization and Optimization of Transparent and Conductive ITO Films Deposited on n and p-types Silicon Substrates <p>The characteristics of enhanced transparent and conductive indium tin oxide (ITO) films on n-type and p-type Si substrates grown by radio frequency (RF) magnetron sputtering were investigated. &nbsp;The structural, optical and electrical properties of the films after annealing at different temperatures ranging from 300°C to 600°C in air were studied. X-ray diffraction (XRD) analysis reveals an amorphous structure for the as-deposited films of both the n-type and p-type Si. The annealed films exhibited a polycrystalline nature with preferential peaks orientation along (222) and (400) crystalline directions. Atomic force microscope (AFM) results indicate smooth surface morphology with increasing roughness as the annealing temperature increases. The surface roughness of the ITO films on the&nbsp; p-type Si was high (6.65 nm) at 500°C and very good microstructures on both Si types were obtained at 500°C. Optical transmittance is enhanced from 89.1 % for the as-deposited film to 95.7 % for film annealed at 500°C in the visible range. ITO films on n-type and p-type Si demonstrate a substantial reduction in their electrical resistivity and sheet resistance with increasing annealing temperature. The ITO/p-Si structure exhibits a low resistivity of 2.45 × 10-5 Ω-cm compared to 7.46 × 10-5 Ω-cm for ITO/n-Si structure. The films performance showed a figure of merit of 14.68 × 10-3 Ω-1 for ITO/n-type Si and 44.74 × 10-3 Ω-1 for ITO/p-type at 500°C indicating that the optimized ITO films on p-type Si can be a promising ITO/p-Si heterojunction for silicon solar cells.</p> A. K. Isiyaku, A. H. Ali, S. G. Abdu, M. Tahan, N. A. Raship, A. S. Bakri, N. Nayan Copyright (c) 2020 A. K. Isiyaku, A. H. Ali, S. G. Abdu, M. Tahan, N. A. Raship, A. S. Bakri, N. Nayan Fri, 04 Dec 2020 15:42:20 +0000