Light Emitting Diode (LED) applications are increasingly used in various microelectronic devices due to their efficient light generation. The miniaturisation of the LED and its integration into compact devices within the weight limit have resulted in excessive heat generation, and inefficient management of this heat could lead to the failure of the entire system. Passive and/or active heat sinks are used for dissipating heat from the system to the environment to improve performance. An ANSYS design modeller and transient thermal conditions were utilised in this study to design and simulate the LED system. The modeller performs its function by utilising the Finite Element Method (FEM) technique. The LED system considered in this work consists of a chip, thermal interface material, and a cylindrical heat sink. The thickness of the Cylindrical Heat Sink (CHS) fins used in the investigation is between 2 mm and 6 mm, whilst ensuring the mass of heat sinks is not more than 100 g. The input power of the LED chip is between 4.55 W and 25.75 W, as required by some original equipment manufacturers (OEMs). A mesh dependency study was carried out to ensure the results were synonymous with what can be obtained practically. The simulation results suggest that the power ratings did not affect the thermal resistance of the CHS. In addition, the thermal resistance increased with the increased thickness of the CHS fin. The efficiencies of the heat sink were found to increase with an increased thickness of the cylindrical fin and the accuracy between the calculated and simulated thermal efficiency ranges from 84.33% to 98.80%. Evidently, the CHS fin of 6 mm thickness is more efficient than the other CHS fins, as depicted in this study.

In recent years, we have witnessed a paradigm shift in mobile operator deployment from Long Term Evolution Advanced (LTE-A) to fifth generation (5G) networks. With the completion of the 3GPP Release 15 standards supporting “Non-Standalone 5G” in late 2018, attention has shifted to Standalone 5G, whilst operators across the globe continue to accelerate deployment of 5G based on the latest specifications. This paper addresses the global trends and challenges for early 5G rollout with focus on the Nigeria market. It also provides solutions to guide Nigerian mobile operator on pitfalls and barriers to entry, to allow smooth transitioning from 4G to 5G technology in Nigeria. Finally, the paper provides empirical evidence suggesting UE connected to the small cells use lower transmit power, hence improving uplink performance.

A new approach to the implementation of the Fredholm integral method (FIM) was developed to evaluate scattering by irregular dielectric particles. In this paper, particles are modeled discretizing their volume with cells according to their weighted contents. The approach to FIM presented in this paper represents a departure from earlier work where the numerical integration is no longer based on expansion in a set of polynomials but on direct spatial integration. This approach which still involves contour integration method uses quandrantal contour in combination with a conditioning weighting function to control the magnitude of the integrand due to the power of the radial variable in the integrand being odd. The strength of our approach lies on the fact that computations are performed in the spatial frequency domain. As a result, the angular scattering pattern is strongly connected to the spatial Fourier transform of the scatterer; hence, for electrically small particles the angular spectrum is relatively smooth and the number of pivots required for integration is relatively low. This technique is well suited to the treatment of scattering from irregular inhomogeneous dielectric particles since only the distribution in space of the dielectric constants needs to be defined. Numerical results also confirm the inadequacy of effective medium theories in evaluating scattering characteristics of inhomogeneous particles.

The next generation of railway customer-oriented services are expected to generate a large volume of data ( $\approx$ 10s of TB). As a result, passengers' applications, safety, security, and Internet-on-Board (IoB) sensors challenge current Train Communication Networks. With the present Ethernet Train Backbone (ETB) specification of just 100 Mbit/s in total, railway passenger services will not support intelligent, seamlessly connected and mobile media on-board trains. In this paper, we propose a novel ETB design with experimental results demonstrating end-to-end 10 Gbit/s and 40 Gbit/s throughput results over existing conducting media on commercial railway carriages. This is equivalent to 100 Mbit/s per user on real-world railway rolling stock and shows that standard RailCat 5e cabling and new rail-approved 10 Gbit/s ETB active nodes (switches) fully support emerging trends and future-proof ETB configurations.