OPTIMIZATION PROCEDURE FOR PRELIMINARY DESIGN STAGE OF CAIRO-DAMIETTA SELF-PROPELLED GRAIN BULK SHIPS

The global logistics center for the storage and handling of grain which will be constructed at Damietta port will extremely increase the annual movement of grain through Cairo-Damietta waterway. Therefore, the demand for inland grain bulk ships has increased significantly in the recent years. This paper introduces a procedure to find out the fleet size and optimum characteristics of self-propelled grain bulk ships working between Cairo and Damietta through River Nile. The characteristics of the Cairo–Damietta waterway are investigated to define the constraints on dimensions and speed for such ship type. Also, mathematical model for the objective function was developed considering: powering, voyage, weight, stability and cost calculation. In this research, Specific cost (Sc), cost of transporting one ton of cargo a distance of one kilometre, is considered as the objective function for this optimization process. This optimization problem is handled as a single objective nonlinear constrained optimization problem using a specially developed computer program. Solutions are generated by varying design variables systematically in certain steps. The best of these solutions is then taken as the estimated optimum. Finally, the problem is presented, the main constrains analyzed and the optimum solution shown

Techno-Economical Optimization for River Nile Container Ships

This work introduces a procedure for the preliminary design of a self-propelled container ship working between Cairo and Aswan through the River Nile. The characteristics of the navigation route from Cairo to Aswan are investigated to defi ne the constraints on dimensions and speed of the River Nile container ships. Also, the dimensions of some existing inland ships are collected and investigated to set limits on the dimensional ratios of such ships. Two empirical formulae, for the determination of ship steel weight and power prediction in the preliminary design stage of conventional self propelled inland container ships, are proposed. This problem is handled as a single objective constrained optimization problem using a specially developed computer program (CACSO). As the required freight rate refl ects the major goal of any commercial ship, it is considered as the objective function for this optimization process. A sensitivity study is carried out to indicate the relative dependence of the objective function on a variety of factors to which the objective function may be sensitive

Stability Analysis for River Nile Floating Hotels

A study of the Egyptian River Nile waterway and its characteristics is made to define the constraints on the dimensions of Nile floating hotels. Factors causing heeling moments or influencing the position of the ship’s centre of gravity, thus affecting the righting moment curve, are discussed in this paper to attain a better stability analysis for Nile floating hotels. Stability of Nile floating hotels can be easily and quickly checked by use of the proposed formula for the critical metacentric height. A mathematical model, for a specially designed computer program, which calculates the maximum sunshade area, is presented. Another proposal, for the calculation of maximum lateral projected area of Nile floating hotels, is presented. The River Nile weather conditions are also investigated to establish a specifi ed wind speed to be used in connection with stability calculation of Nile fl oating hotels

Techno-Economical Optimization for River Nile Container Ships

This work introduces a procedure for the preliminary design of a self-propelled container ship working between Cairo and Aswan through the River Nile. The characteristics of the navigation route from Cairo to Aswan are investigated to defi ne the constraints on dimensions and speed of the River Nile container ships. Also, the dimensions of some existing inland ships are collected and investigated to set limits on the dimensional ratios of such ships. Two empirical formulae, for the determination of ship steel weight and power prediction in the preliminary design stage of conventional self propelled inland container ships, are proposed. This problem is handled as a single objective constrained optimization problem using a specially developed computer program (CACSO). As the required freight rate refl ects the major goal of any commercial ship, it is considered as the objective function for this optimization process. A sensitivity study is carried out to indicate the relative dependence of the objective function on a variety of factors to which the objective function may be sensitive

Response surface optimisation of vertical axis wind turbine at low wind speeds

The Vertical Axis Wind Turbines (VAWTs) have an increasing global market and this emphasis the need for to improve the performance of VAWTs, especially at relatively low wind speed. This paper utilises the Response Surface methodology to optimise the performance of a VAWT. A three bladed VAWT configuration was considered with a NACA0015 profile. Three significant input parameters were selected including the tip speed ratio, the turbine solidity, and the pitch angle. An extended range of each input parameter was chosen in order to gain a good insight into how these input parameters affect the performance of the VAWT. The high-fidelity Computational Fluid Dynamics (CFD) simulations were carried out for the modelling of the turbine. The use of the Response Surface Optimisation based on Multi-Objective Genetic Algorithm (MOGA) along with the CFD simulations is found to be useful in the selection of the optimal design of VAWT. Moreover, the 3D aspects of the VAWT geometry are investigated and these include the turbine aspect ratio and the effect of the blade tip geometry. The implementation of an optimised winglet at the tip of the turbine blades is found to provide a significant enhancement of the cycle averaged power coefficient, especially at low aspect ratios

Nitrogen and Iron Availability Drive Metabolic Remodeling and Natural Selection of Diverse Phytoplankton during Experimental Upwelling

Nearly half of carbon fixation and primary production originates from marine phytoplankton, and much of it occurs in episodic blooms in upwelling regimes. Here, we simulated blooms limited by nitrogen and iron by incubating Monterey Bay surface waters with subnutricline waters and inorganic nutrients and measured the wholecommunity transcriptomic response during mid- and late-bloom conditions. Cell counts revealed that centric and pennate diatoms (largely Pseudo-nitzschia and Chaetoceros spp.) were the major blooming taxa, but dinoflagellates, prasinophytes, and prymnesiophytes also increased. Viral mRNA significantly increased in late bloom and likely played a role in the bloom\u27s demise. We observed conserved shifts in the genetic similarity of phytoplankton populations to cultivated strains, indicating adaptive population-level changes in community composition. Additionally, the density of single nucleotide variants (SNVs) declined in late-bloom samples for most taxa, indicating a loss of intraspecific diversity as a result of competition and a selective sweep of adaptive alleles. We noted differences between mid- and late-bloom metabolism and differential regulation of light-harvesting complexes (LHCs) under nutrient stress. While most LHCs are diminished under nutrient stress, we showed that diverse taxa upregulated specialized, energy-dissipating LHCs in low iron. We also suggest the relative expression of NRT2 compared to the expression of GSII as a marker of cellular nitrogen status and the relative expression of iron starvationinduced protein genes (ISIP1, ISIP2, and ISIP3) compared to the expression of the thiamine biosynthesis gene (thiC) as a marker of iron status in natural diatom communities

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

OPTIMIZATION PROCEDURE FOR PRELIMINARY DESIGN STAGE OF CAIRO-DAMIETTA SELF-PROPELLED GRAIN BULK SHIPS

The global logistics center for the storage and handling of grain which will be constructed at Damietta port will extremely increase the annual movement of grain through Cairo-Damietta waterway. Therefore, the demand for inland grain bulk ships has increased significantly in the recent years. This paper introduces a procedure to find out the fleet size and optimum characteristics of self-propelled grain bulk ships working between Cairo and Damietta through River Nile. The characteristics of the Cairo–Damietta waterway are investigated to define the constraints on dimensions and speed for such ship type. Also, mathematical model for the objective function was developed considering: powering, voyage, weight, stability and cost calculation. In this research, Specific cost (Sc), cost of transporting one ton of cargo a distance of one kilometre, is considered as the objective function for this optimization process. This optimization problem is handled as a single objective nonlinear constrained optimization problem using a specially developed computer program. Solutions are generated by varying design variables systematically in certain steps. The best of these solutions is then taken as the estimated optimum. Finally, the problem is presented, the main constrains analyzed and the optimum solution shown