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The purpose of this study is to forecast the mechanical properties of ternary blended concrete (TBC) modified with oyster shell powder (OSP) and shea nutshell ash (SNA) using deep neural network (DNN) models.

DNN models with three hidden layers, each layer containing 5–30 nodes, were used to predict the target variables (compressive strength [CS], flexural strength [FS] and split tensile strength [STS]) for the eight input variables of concrete classes 25 and 30 MPa. The concrete samples were cured for 3–120 days. Levenberg−Marquardt's backpropagation learning technique trained the networks, and the model's precision was confirmed using the experimental data set.

The DNN model with a 25-node structure yielded a strong relation for training, validating and testing the input and output variables with the lowest mean squared error (MSE) and the highest correlation coefficient (R) values of 0.0099 and 99.91% for CS and 0.010 and 98.42% for FS compared to other architectures. However, the DNN model with a 20-node architecture yielded a strong correlation for STS, with the lowest MSE and the highest R values of 0.013 and 97.26%. Strong relationships were found between the developed models and raw experimental data sets, with R² values of 99.58%, 97.85% and 97.58% for CS, FS and STS, respectively.

To the best of the authors’ knowledge, this novel research establishes the prospects of replacing SNA and OSP with Portland limestone cement (PLC) to produce TBC. In addition, predicting the CS, FS and STS of TBC modified with OSP and SNA using DNN models is original, optimizing the time, cost and quality of concrete.

In recent times, science and technology has taken a front seat in revolutionizing agricultural production and food processing globally with noticeable impact on food, nutrition and family health. This study was carried out to have a critical review of genetically modified (GM) foods and the use of GM and biofortified crops for food security in developing countries where foods are not adequately available and people are not food secured.

A critical review of GM foods was undertaken and the use of GM and biofortified crops for food security in developing countries where foods are not adequately available and people are not food secured was carried out.

Currently, there are no recent patents on GM and biofortified crops and this shows that there are more works to be done by policymakers, regulatory agencies, consumers and right organizations on environmental, health and biosafety of GM and biofortified crops. Advances in science and technology have changed our relationship with nature which enables crops to be modified and improved through selective breeding to obtain more stronger and productive crops. However, despite the benefits and improvements from GM and biofortified crops, controversy and arguments have continued to trail the consumption of GM and biofortified crops because of the perceived safety issues. Although genetic engineering has helped in developing fast-growing and pest-resistant crops, as well as reduction in use of pesticides, however, its impact on the environment and the consumers cannot be overemphasized. In conclusion, this study showed that the role of GM and biofortified crops for food security is the subject of public controversy; however, genetic engineering has the potential to improve world food production, increase food availability and influence farmers’ income and thus their economic access to food but the attendance potential risks related to food safety and avoidable environmental hazards should not be overlooked. There is need for comprehensive information on the impact of GM and biofortified crops on environment, human health and biosafety of the crops.

Few available literatures on the subject matter were critically reviewed.

The paper helps in creating awareness for more in-depth research on GM and biofortified crops and their impacts on food security in developing countries where foods are not adequately available and people are not food secured.

This research is of value to the researchers, policymakers and regulatory agencies in developing countries on food safety.

A novel cost-effective bio-digester was explored to convert biological waste into useful clean energy. The bioreactor was aimed to anaerobically digest locally sourced cow dung and chicken droppings.

The design consideration is a batch horizontal 267 L digester made from cast iron with centrally positioned four-impeller shaft to enhance mixing. The system operated with a retention time of 63 days and a substrate (cow dung and poultry waste) ratio of 1:2 and water substrate ratio of 1:0.5 in the gasholder system. The purification, compression and performance evaluation of the generated biogas were also conducted.

The total volume of gas produced for each substrate compositions designed over 14 days ranges between 49.34 and 52.91 mL/day. The optimal value of 52.45 ml using cow dung and poultry waste (w/w) 20:80 was obtained. The average ambient temperatures during the study were within the mesophilic range of 20-40°C. The pH values were stable and always in the optimal range of 6.5-8.0. The reductions in moisture content, ash content, total solids and volatile solids were from 80.50-0.20 per cent, 39.60-14 per cent, 18.50-5.90 per cent and 11.60-4.90 per cent, respectively.

The developed digester is cost-effective and would help minimize solid waste disposal. The estimated methane contents of the gas from cow dung and chicken waste after scrubbing were found to be 71.95 per cent and could be harnessed in solving the energy crisis in the developing nations.