9 research outputs found
A comparative study of Zinc (II) ions removal by a locally produced Granular activated carbon
No full textPhysiochemical properties of wastewater effluent from the plants of a brewery in Lagos, Nigeria were analyzed. The adsorption capacity of Granular activated carbon from animal horns when compared with the available commercial Granulated Activated Carbon (GAC) has been presented. Kinetics of adsorption was also investigated. The adsorption isotherms could be well defined with Freundlich model instead of Langmuir model for both GAC studied. The experimental data, when applied to the first and second-order kinetic models, followed the first-order with r² = 0.931 for GAC from animal horns while commercial GAC followed the second-order with r² = 0.936. The results illustrated how animal horns, a solid waste disposal menace from the abattoir at the Oshodi market in Lagos metropolis, was used as an effective biosorbent for the removal of Zn2+ ions; offering a cheap option for primary treatment of the wastewater effluent.Keywords— Biosorption, animal horns, Granulated Activated Carbon, wastewater, effluen
Application of Luffa Cylindrica in Natural form as Biosorbent to Removal of Divalent Metals from Aqueous Solutions - Kinetic and Equilibrium Study
No full textNon
Artificial neural network modeling for potential performance enhancement of a planar perovskite solar cell with a novel TiO2/SnO2 electron transport bilayer using nonlinear programming
No full textThe performance of a planar Perovskite Solar Cell (PSC), having a novel TiO2/SnO2 bilayer as Electron Transport Layer (ETL), has been optimized. To achieve this, an artificial neural network (ANN) was trained to predict the Power Conversion Efficiency (PCE) as a function of five technological parameters of the PSC namely; Active layer thickness, Hole Transport Layer (HTL) thickness, HTL dopant concentration, Electron Transport Layer (ETL) thickness, and ETL dopant concentration. The model was able to predict the data accurately, with an overall Mean Square Error (MSE) of 0.0002302, Root Mean Square Error of (RMSE) of 0.01502, Sum of Squares Error of (SSE) of 0.4712, and correlation coefficient (R) of 0.9991. Subsequently, the optimum values of independent variables giving the maximum efficiency were determined by applying the Particle Swarm Optimization algorithm to maximize the ANN-derived model. The optimum solutions predicted were then simulated using the SCAPS 1-D program, yielding a PCE of 14.94%. This paper presents a straightforward and efficient methodology by which ANN modeling and nonlinear programming can be applied to carry out multi-property optimization of PSC performance
Modelling And Simulation Of Hydrogen Production Plant for Minimum Carbon Dioxide Emission
No full textAbstract
The use of coal as a source of energy for hydrogen production is desirable because it is widely available, inexpensive, and guarantees long-term availability compared to natural gas. In this study, modeling and simulation of a hydrogen production plant from coal gasification was carried out. The study also optimized process variables affecting hydrogen production for minimum carbon dioxide emissions. Modeling and simulation of a hydrogen plant was carried out using ASPEN One Suites Ver. 11 software, while optimization of process variables was done using response surface methodology (RSM). Central Composite Design (CCD) was used to design the process variables such as carbon ratio (0.715-0.75), gasification temperature (1023.15 –1223.15 K), and pressure (1-3 MPa). The independent variables for hydrogen generation and carbon dioxide emissions (CO2e-) were correlated using a quadratic model The coal gasification parameters were optimized numerically using the desirability function to maximize the hydrogen produced and minimize the CO2e-. The results reveal that gasification temperature has a greater effect on maximizing hydrogen production and carbon dioxide emission (CO2e-) reduction. Results also showed the optimal conditions for minimizing the cost and maximizing the hydrogen production: a gasification temperature of 1223.15 K, an oxygen to coal ratio of 0.715, and a gasification pressure of 1 MPa.
Keywords: Hydrogen production, optimization, ASPEN, gasification, RSM, Coal Energy
Proactive safety culture in Nigeria through engineering education: A key to the prevention of catastrophic incidents in the industry
No full textAdvances made in promoting a culture of preparedness through disaster risk reduction (DRR) initiatives are strong building blocks to promote more comprehensive changes at the policy level and strengthen resilience in the everyday lives of children, families, schools, and the communities they serve. Proactive safety entails constantly ensuring the safety efficacy of systems, procedures, and people. Process safety entails the identification and understanding of potential hazards, the evaluation of consequences, safeguards, and risks, and the addition of layers of protection to prevent and/or mitigate incidents. The purpose of this study is to review the proactive safety culture in Nigeria through engineering education as a key to the prevention of catastrophic incidents in the industry. A strong safety culture is required to protect employees, but it is especially important for protecting students and developing their skills and awareness of safety. A questionnaire was developed to obtain feedback from industry experts and other stakeholders on the appropriate contents of an undergraduate course on safety that will produce safety-conscious engineering graduates and ultimately a culture of safety in Nigeria. These questions were asked in the following areas: safety assessment in Nigeria, importance of safety education, and safety courses for engineering students. Based on the responses from the 250 questionnaires distributed and 208 responses, a safety course curriculum was suggested with a possible 30 course outlines that could support students at different stages in their development, and as such, it would be expected that students’ safety skills improve as they progress through their degree
Two alternative pathways for docosahexaenoic acid (DHA, 22:6n-3) biosynthesis are widespread among teleost fish
No full textDocosahexaenoic acid (DHA) plays important physiological roles in vertebrates. Studies in rats and rainbow trout confirmed that DHA biosynthesis proceeds through the so-called "Sprecher pathway", a biosynthetic process requiring a Δ6 desaturation of 24:5n-3 to 24:6n-3. Alternatively, some teleosts possess fatty acyl desaturases 2 (Fads2) that enable them to biosynthesis DHA through a more direct route termed the "Δ4 pathway". In order to elucidate the prevalence of both pathways among teleosts, we investigated the Δ6 ability towards C24 substrates of Fads2 from fish with different evolutionary and ecological backgrounds. Subsequently, we retrieved public databases to identify Fads2 containing the YXXN domain responsible for the Δ4 desaturase function, and consequently enabling these species to operate the Δ4 pathway. We demonstrated that, with the exception of Δ4 desaturases, fish Fads2 have the ability to operate as Δ6 desaturases towards C24 PUFA enabling them to synthesise DHA through the Sprecher pathway. Nevertheless, the Δ4 pathway represents an alternative route in some teleosts and we identified the presence of putative Δ4 Fads2 in a further 11 species and confirmed the function as Δ4 desaturases of Fads2 from medaka and Nile tilapia. Our results demonstrated that two alternative pathways for DHA biosynthesis exist in teleosts. © 2017 The Author(s).A.O. is a Commonwealth scholar funded by the Commonwealth Scholarship Commission (NGCS-2014-438) in the UK. N.K. was funded by the Japan Society for the Promotion of Science through Grant-in-Aid for JSPS Research Fellow. DRT and OM were partly supported by the Major International Joint Research Project from the National Natural Science Foundation of China (NSFC) (No. 31110103913)
Do differences in the scale of irrigation projects generate different impacts on poverty and production?
No full textThis paper investigates differences in household production and consumption among small- and large-scale irrigators to assess whether the scale of an irrigation project increases household welfare in Mali. Much of the evidence of the impact of irrigation does not use counterfactual analysis to estimate such impact or distinguish between the scale of the irrigation projects to be evaluated. In the dataset collected by the author, both a large-scale irrigation project and small-scale projects are used to construct counterfactual groups. Propensity score matching is used to estimate the average treatment effect on the treated for small and large irrigators relative to nonirrigators on agricultural production, agricultural income, and consumption per capita. Small-scale irrigation has a larger effect on agricultural production and agricultural income than large-scale irrigation, but large-scale irrigation has a larger effect on consumption per capita. This suggests that market integration and nonfarm externalities are important in realizing gains in agricultural surplus from irrigation.Irrigation, program evaluation,
Global, regional, and national trends in routine childhood vaccination coverage from 1980 to 2023 with forecasts to 2030: a systematic analysis for the Global Burden of Disease Study 2023
No full textBackground: Since its inception in 1974, the Essential Programme on Immunization (EPI) has achieved remarkable success, averting the deaths of an estimated 154 million children worldwide through routine childhood vaccination. However, more recent decades have seen persistent coverage inequities and stagnating progress, which have been further amplified by the COVID-19 pandemic. In 2019, WHO set ambitious goals for improving vaccine coverage globally through the Immunization Agenda 2030 (IA2030). Now halfway through the decade, understanding past and recent coverage trends can help inform and reorient strategies for approaching these aims in the next 5 years. Methods: Based on the Global Burden of Diseases, Injuries, and Risk Factors Study 2023, this study provides updated global, regional, and national estimates of routine childhood vaccine coverage from 1980 to 2023 for 204 countries and territories for 11 vaccine-dose combinations recommended by WHO for all children globally. Employing advanced modelling techniques, this analysis accounts for data biases and heterogeneity and integrates new methodologies to model vaccine scale-up and COVID-19 pandemic-related disruptions. To contextualise historic coverage trends and gains still needed to achieve the IA2030 coverage targets, we supplement these results with several secondary analyses: (1) we assess the effect of the COVID-19 pandemic on vaccine coverage; (2) we forecast coverage of select life-course vaccines up to 2030; and (3) we analyse progress needed to reduce the number of zero-dose children by half between 2023 and 2030. Findings: Overall, global coverage for the original EPI vaccines against diphtheria, tetanus, and pertussis (first dose [DTP1] and third dose [DTP3]), measles (MCV1), polio (Pol3), and tuberculosis (BCG) nearly doubled from 1980 to 2023. However, this long-term trend masks recent challenges. Coverage gains slowed between 2010 and 2019 in many countries and territories, including declines in 21 of 36 high-income countries and territories for at least one of these vaccine doses (excluding BCG, which has been removed from routine immunisation schedules in some countries and territories). The COVID-19 pandemic exacerbated these challenges, with global rates for these vaccines declining sharply since 2020, and still not returning to pre-COVID-19 pandemic levels as of 2023. Coverage for newer vaccines developed and introduced in more recent years, such as immunisations against pneumococcal disease (PCV3) and rotavirus (complete series; RotaC) and a second dose of the measles vaccine (MCV2), saw continued increases globally during the COVID-19 pandemic due to ongoing introductions and scale-ups, but at slower rates than expected in the absence of the pandemic. Forecasts to 2030 for DTP3, PCV3, and MCV2 suggest that only DTP3 would reach the IA2030 target of 90% global coverage, and only under an optimistic scenario. The number of zero-dose children, proxied as children younger than 1 year who do not receive DTP1, decreased by 74·9% (95% uncertainty interval 72·1-77·3) globally between 1980 and 2019, with most of those declines reached during the 1980s and the 2000s. After 2019, counts of zero-dose children rose to a COVID 19-era peak of 18·6 million (17·6-20·0) in 2021. Most zero-dose children remain concentrated in conflict-affected regions and those with various constraints on resources available to put towards vaccination services, particularly sub-Saharan Africa. As of 2023, more than 50% of the 15·7 million (14·6-17·0) global zero-dose children resided in just eight countries (Nigeria, India, Democratic Republic of the Congo, Ethiopia, Somalia, Sudan, Indonesia, and Brazil), emphasising persistent inequities. Interpretation: Our estimates of current vaccine coverage and forecasts to 2030 suggest that achieving IA2030 targets, such as halving zero-dose children compared with 2019 levels and reaching 90% global coverage for life-course vaccines DTP3, PCV3, and MCV2, will require accelerated progress. Substantial increases in coverage are necessary in many countries and territories, with those in sub-Saharan Africa and south Asia facing the greatest challenges. Recent declines will need to be reversed to restore previous coverage levels in Latin America and the Caribbean, especially for DTP1, DTP3, and Pol3. These findings underscore the crucial need for targeted, equitable immunisation strategies. Strengthening primary health-care systems, addressing vaccine misinformation and hesitancy, and adapting to local contexts are essential to advancing coverage. COVID-19 pandemic recovery efforts, such as WHO's Big Catch-Up, as well as efforts to bolster routine services must prioritise reaching marginalised populations and target subnational geographies to regain lost ground and achieve global immunisation goals. Funding: The Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance
