Theoretical Evaluation of Required PlasticWork in Bulging of Statically loaded Plate

Finding the amount of plastic deformation into metallic plates,metallicstructures, ships frame, bodies of different types of cylinders and reservoirsbodies as a result of exposure tostaticor dynamic forceis so necessary todetermine the extent ofdistortionand destructionhappening intheseobjects and this is one of the main factors in design calculations to determine the dimensions and thicknesses of these bodies. Derivation anew theoreticalmodelto calculate theamount of work and forcerequired to bulge the sheet metalisa very important targetbecause of the lack of a theoretical relations to calculate the work of plastic deformation with good approximationoridenticalto exact required work and force; or vice-versa to find the amount of plastic deformation as a result of a specific work or specific force.This was donein this research where a theoretical model has been derivedthrough the expense of work and force necessary to generatebulging in sheet metal. This theoretical model has been adopted on the mildsteel plates which are of wide application in practical life. Results obtained from the theoretical model were compared with those obtained from tests conducted onsimply supported circular steel plates made from low carbon steel ,milled steel , of a (280) mm diameter and (1,2, 3, 4,5, 6, 8,10) mm thickness andexposed to central force applied by a flat ended punch of 10 mm diameter. The applying force was increased gradually till it caused plastic deformation in the sheet, and then reached the state of shear of the disk, which is locatedunder the punch. Results comparison appear matchorsubstantial convergence between the practical resultsand those obtained from the theoretical model to find the work and for ceit takes to plastic deformation in the tested plates

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century