Wearable stitched transmission lines made from stripped RG174 and textile materials are introduced for broadband operations. The stitched transmission lines which are 150 mm long consists of an inner conductor surrounded by a tubular insulating layer. For shielding purposes, the structures are stitched into a denim material with conductive threads. The performances of the stitched transmission lines with three different stitch patterns, Double Overlock, Flatlock stitch and Ric-Rac stitch were investigated and results obtained confirm that Ric-Rac stitched transmission line has fewer DC losses than the three stitched transmission lines for frequencies up to 1 𝐺𝐻𝑧. However, beyond that up to 2.4 𝐺𝐻𝑧 and above, it was observed that the Flatlock stitched transmission line and the Double Overlock stitched transmission line have fewer radiation losses compared to the Ric-Rac stitched transmission line. Similarly, the performance of the stitched transmission line when bent through curved angles of 90° and 180° was considered, and a much better S21 was observed with a curved angle of 180° for frequencies below 2.1 𝐺𝐻𝑧, with radiation loss increasing afterwards. Finally, the sensitivity of the design to manufacturing tolerances, with changes in cross-sectional dimensions of the stitched transmission line and the transmission characteristics with different textile substrates were both considered. While simulated results showed that the stitched transmission line is sensitive to small variations in its circular dimensions, measured results conversely showed that Denim and Felt materials can be used as a substrate without any significant effect on its propagation characteristics.

A Decision Support System (DSS) is a useful information systems tool that supports decision-making as it aids institutional admission committees in effective and efficient decision-making. Several types of admission DSS are said to have existed over time. However, for most of the admission DSS as seen from the literature reviewed, soft copies of data are obtained from a source and uploaded onto the system, whereas, the DSS can be made to obtain data directly from the source into itself, thereby speeding up system procedures. The objectives of this study, are to develop an Application Programming Interface (API) and use mathematical methods of weighted grade points for ranking and provision of information for sensitive admission analysis and decision-making. The method of inquiry used in this study was inductive, geared majorly towards consultations of research papers, relevant materials such as educational journals, publications, websites etc., and resource persons through oral interviews. This study adopts a qualitative approach, by studying admission DSS with the aim of improving the existing systems. A Use-case scenario was used as a design model and the system architectural model and program flow were demonstrated as well. Thus, the DSS developed in this study referred to as AARISYS (Automated Admission Ranking System), was implemented using scripting (PHP & JavaScript) and markup languages (HTML & CSS) with MySQL. The web-based system fetches Applicants' data from an external Database (source) via an API, store and assign rank scores. Validation and defect tests were also used and the system results were displayed. Thus, with the aid of API, admission DSS can now obtain data from sources by itself, in contrast to the methods of inputting soft copied data, as used by other DSS.

Spinel LiMn2O4 offers a potentially attractive alternative to the commercialized LiCoO2 because of its low cost, non-toxicity, good rate performance and superior safety, but experiences severe capacity fading as a result of Jahn-Teller cubic phase transition to unstable tetragonal phase especially when operated at elevated temperature (>55oC). Among the various techniques carried out to overcome these setbacks is doping with cations to raise the oxidation state of Mn thereby decreasing the amount of unstable Mn3+. This study focuses on the investigation of the structural and electronic properties of Cu2+ doped LiMn2O4 using ab-initio computational method. The structural properties of both un-doped LiMn2O4 and Cu2+ doped LiMn2O4 were collectively obtained using both generalized gradient approximation (GGA) employing pseudo-potentials, plane wave basis sets and XcryDen. From the electronic properties of undoped LiMn2O4, it was revealed that in LiMn2O4, only Mn3+ ions contribute to conduction, even though Mn3+ ions and Mn4+ ions exist together. Increasing the number of Mn3+ brings it a unique challenge of instability. Due to this instability, avoiding the Mn3+ state of manganese prevents Jahn-teller distortion, resulting in a reduced phase transition. Based on the results from the first-principles calculation of Cu2+ doped LiMn2O4, the Cu valence in doped spinel LiCu0.25Mn0.75O4 is Cu2+ at a fully lithiated state. When half of the Li ions are extracted, the Cu2+ ions oxidized to Cu3+ ions. Since Cu2+ is a di-valent element, the dopant act as electrochemically active centres for valence change, leaving two trivalent ions to only take on +4 oxidation states stably, thus increasing Mn-O bonding strength which ultimately suppressed Jahn-Teller distortions. However, previous studies show that Cu2+ substitution shrinks the lattice because the ionic radius of Cu2+ is smaller than that of the host Mn3+ ions, thereby the reversible capacity of Cu-doped spinel may be reduced as Cu ions can only provide one electron per ion.

In this paper, the structural geometry, electronic and magnetic properties of single magnesium (Mg) and vanadium (V) atoms doped 4H-SiC system were investigated. For the structural geometry of each sample, the energy substitution, as well as bond length, were calculated; results obtained indicate that the bond length of Silicon-Magnesium (Si-Mg) and SiliconVanadium (Si-V) was 1.90 Å and 2.02 Å respectively, greater than that of silicon-carbon (SiC) 1.89 Å in pure SiC. This result indicates that the bond length increases due to the introduction of dopants with greater radii than that of Si. It also shows that both Mg and V doping changes the structure from non-magnetic ordering to magnetic in nature. The band structure result for both undoped and doped shows the presence of valence band maximum (VBM) and conduction band minimum (CBM) around different symmetry points which indicate an indirect band gap nature. The calculated band gap of pure 4H SiC is found to be ~ 2.21 eV, which is at a wide band gap material range, but with the introduction of Mg and V dopants, the band gap reduced significantly to ~0.4 eV and ~0.45 eV respectively. The density of state (DOS) and projected density of state (PDOS) show the contributions of the various states in both the VBM and CBM; after doping the Fermi energy is shifted towards higher energy and enters into the conduction band, exhibiting spin polarization. Both DOS and PDOS indicated that the magnetic moments mainly come from the 2p orbitals of Si atoms and 3p for Mg dopant and 3d orbitals for V dopant. The magnetic moment for 4H-SiC/Mg and 4H-SiC/V was calculated to be 2.23 μB and 3.24 μB.