Modelling COVID 19 Epidemics: The Role of Social Distancing and Isolation

Coronavirus disease 2019 pandemic, popularly known as the COVID 19 pandemic, was one of the most dreaded pandemics in the history of human epidemiology. It negatively impacted the health and economy of the whole world, leading to a global economy shutdown. This study aims to develop a mathematical model for COVID 19 transmission to investigate the role of social distancing and isolation. Therefore, a mathematical model for COVID 19 incorporating social distancing and isolation of exposed and infectious individuals as controls were formulated. The basic reproduction number, as an epidemic threshold, was computed by the next-generation approach. The model has a globally asymptotically stable disease-free equilibrium whenever the basic reproduction number is less than unity. The numerical results show that whilst COVID 19 can spark a major epidemic in the absence of control. It can be contained with optimum enforcement of rules. The findings of this study reveal that an optimum combination of social distancing and isolation as a control strategy is the most effective and is therefore recommended

On a Two-Sex Model for Gonorrhea Transmission Dynamics Incorporating Treatment and Condom Use

In  this study we  developed a two sex model for gonorrhea transmission dynamics incorporating treatment and condom use as control measures using a system of ordinary differential equations. We further derive an epidemic threshold as the effective reproduction number,  using the next generation method. We established both the disease-free equilibrium and endemic equilibrium states using the linearization method and the manifold theory respectively. From the analysis of the model and results, it was shown that, the disease free equilibrium state is locally and asymptotically stable if  The implication is that gonorrhea can be eliminated fro the population if the effective reproduction number, is less than unity. The endemic equilibrium state is locally and asymptotically stable for  and this implies that gonorrhea disease can spread and there could disease persistence. Key words: Gonorrhea disease, effective reproduction number, equilibrium state, centre manifold theory

On Simulation of the Effect of Compatibility Test on the Transmission Dynamics of HIV in a Heterosexual Population

Tests to determine genotypes, HIV status of partners are nowadays conducted to ascertain their compatibility for marriage or other forms of sexual relationships. The objective of this article is to simulate the effect of compatibility test compliance parameter on the transmission dynamics of HIV.  A mathematical model of HIV incorporating compatibility test compliance parameter is presented. A unique disease-free equilibrium state was determined, indicating possibility of control of HBV disease. The model was solved numerically using Runge-Kutta method of order four to determine the sensitivity of the model solution to this parameter. The results of the numerical simulations of the model show that effective compatibility compliance as a control strategy can eradicate HIV disease. Finally, these findings strongly suggest that high level of compatibility compliance is crucial to the success of HIV disease control. Key words: HIV, mathematical model, disease-free equilibrium, endemic equilibriu

Production of Eco-Friendly Brake Pad Using Raw Materials Sourced Locally In Nsukka

In this study, high quality asbestos free bake pad was produced from locally sourced raw materials. The disc brake friction lining with geometrical specification of Mitshibushi L-300 was produced using palm kernel shell and coconut shell powder as base material, polyester resin as binder material, graphite as lubricant, metal chips and carbides as the abrasives. A commercially bought brake pad served as control. Three different samples were produced by varying mass compositions of palm kernel shell and coconut shell. Sample A has equal mass of palm kernel shell (PKS) and coconut shell (CNS). Sample B has higher mass of PKS (83.03%) and lower mass of CNS (12.68%) while Sample C has lower mass of PKS (14.79%) and higher mass of CNS (35.92%). A constant pressure of 16.75kN/m2 and particle size of 0.63um were used for all samples. The binder, lubricant and abrasive composition were kept constant. The test result showed that the coefficient of friction (static and dynamic) for samples A, B and C were (0.374, 0351), (0.383, 0354) and (0.362, 0.349) while the commercial pad was (0.388, 0.359). Percentage water absorption for samples A, B and C were 0.0522, 0.0399 and 0.0470 while the commercial pad was 0.0327.  The hardness test results for sample A, B and C gave 3.3, 3.41 and 3.0 while the commercial pad was 2.53. The wear rate test gave 0.00366g/sec, 0.00456g/sec, 0.00334g/sec, 0.00312g/sec for samples A, B, C and commercial pad respectively. All the samples were tested under the same conditions . Sample C has a promising potential since it had a moderate water absorption, wear rate and hardness but had the least coefficient of friction. Keywords: Brake Pad, Palm Kermel Shell, Coconut Shell, Resin,

Thermodynamic Optimization of Steam Boiler Parameter Using Genetic Algorithm

In this paper, genetic algorithm implemented in Matlab is used for the optimization of the boiler unit at Egbin power plant. Based on thermodynamic consideration of a boiler, the thermal efficiency of the boiler for 2008 and 2009 is computed. The thermal efficiency is defined as the objective function and is  maximized using genetic algorithms subject to a list of constraints for obtaining the numerical values of the optimum operating parameters. These determined optimum operating parameters will serve as basis for improving the performance of the power plant and this is the significance of this study.    The effects of genetic algorithm options (such as initial population, elite children, and crossover ratio) on the optimization results are also established. It is observed that applying genetic algorithm in the thermodynamic optimization of a case study (Egbin power plant) boiler, the percentage increase in the thermal efficiency is 4.76% and 3.89% in comparison with the existing values for the studied boiler at Egbin thermal power plant for 2008 and 2009 respectively. Keywords: Thermodynamics, Optimization, Genetic Algorithm, Steam Boiler, Power Plant.

Mathematical model for the transmission dynamics of Lassa fever with control

In this work, we proposed a mathematical model for transmission dynamics of Lassa fever by incorporating isolation and treatment as control strategies. The disease free equilibrium state of the model was obtained, and used to derive the basic reproduction number, 0 using the next generation method. We further proved that the disease free equilibrium state is locally asymptotically stable whenever the reproduction number is less than unity. The numerical simulations revealed that the infection transmission rate constitute an essential parameter for an epidemic to occur, thus efforts should geared at bringing the infection transmission parameter to the lowest level to ensure eradication. The simulations further revealed that combined effective treatment and isolation of infected individuals are vital to eradicating the disease transmission

An Invading Stent: Conservative Management of a Penetrating Splenic Injury by a Migrated Pancreatic Duct Stent

Pancreatic duct (PD) stenting is a common treatment modality for PD calculi or strictures, which are common complications of chronic pancreatitis. PD stent migration is a described complication of the procedure. Penetrating splenic injury may result in life-threatening hemorrhage, often requiring splenic artery embolization or splenectomy. Herein, we describe a unique case of a 49- year-old female with chronic pancreatitis and PD stent who presented with abdominal pain. A computed tomography of her abdomen revealed the distal end of her PD stent to have migrated internally through her spleen with an associated perisplenic fluid collection. After initial clinical stabilization she underwent an endoscopic retrograde cholangiopancreatography which revealed the proximal end of the migrated stent in the duodenum and the stent was successfully with improvement in clinical status

COVID-19 pandemic waves: how prepared is West Africa for managing a high COVID-19 caseload? Urgent actions needed

The ECOWAS Region and the world have learnt a lot in the last year and a half concerning the pandemic. As the pandemic continues to evolve, the region needs to put together all these lessons in other to better protect its people, rebuild its economy and strengthen the regional health security for better regional prosperity. We reviewed the response mounted by the region from January 2020 to July 2021 and the existing body of knowledge. We recommend that the region quickly increase the COVID-19 immunization coverage, sustain the enhance genomic surveillance, improve testing and the strengthen point of entry surveillance

Investigation of the normal blowing approach to controlling wingtip vortex using LES

The characteristics and control of a wingtip vortex are of great significance when considering drag reduction and flight safety of transportation aircrafts. The associated aerodynamic phenomenon resulting from rolling up of a wingtip vortex includes boundary layer flow, shear layer separation, and vortex breakdown, while the interaction of a wingtip vortex with the airframe causes induced drag, wingtip noise, etc. This paper studies a normal blowing method utilized to control the wingtip vortex. Large eddy simulation (LES) technique applied to a straight NACA0012 wing having a chord length (c) of 0.4 m is adopted for this study. The Reynolds number based on the chord length is 1:6 × 106 and the angle of attack is 12° . The computational approach utilized the dynamic Smagorinsky-Lilly subgrid model for 3D simulations. Normal blowing from a high aspect ratio jet from the wingtip lower surface was used to control the wingtip vortex. From 0.05c to 0.30c, the blowing slit width was 1 mm, with the slit exit treated as a velocity inlet boundary condition which supplied the blowing jet with a momentum coefficient of 0.28%. Results of axial velocity and span-wise pressure distribution of the clean airfoil presented good agreement with known experimental data. LES results indicate that normal blowing suppresses the primary vortex strength, while the vortex core radius, maximum induced velocity, axial vorticity flux, and pressure peak of the primary vortex are reduced by 25%, 28%, 46%, and 52%, respectively. Flow field structures before and after blowing show that blowing suppresses the shedding, coiling, and convergence of the free vortex layers near the primary vortex. This study also shows that normal blowing generates a jetinduced vortex at the location of the secondary vortex, while backflow, volume expansion, and spiral burst can be observed in the jet-induced vortex. The bursting jet-induced vortex destroys the jet-like flow structure of the primary vortex at the trailing edge

A Novel Method for Defining the Leeward Edge of the Planar Jet in Crossflow

To avoid the complexity of the edge definition by the half width, a new approach to defining the leeward edge of the planar jet in crossflow is introduced in this paper. Particle Image Velocimetry (PIV) experiments were performed to measure different flow regimes within the single jet and the dual jets configurations in crossflow. Based on the experimental data acquired, a series of velocity profiles were extracted from the flow field. In each profile, a velocity threshold was given to distinguish the regions sheltered and the regions not sheltered by the planar jet. The boundary of these regions was accordingly recognized as the leeward edge. Furthermore, fitting of the edge was carried out using a second order polynomial so as to enable a mathematical expression of the leeward edge. An application of the proposed approach towards the flow induced noise reduction using a planar jet is also discussed in this paper. In addition, the PIV frame assembly algorithm used in this study is reported