Prediction of emissions and profits from a biomass, tyre, and coal fired co-gasification CHP plant using artificial neural network: Nigerian and South African perspectives

Abstract : The local sourcing of feedstock for energy generation will reduce costs in the power plant, and promote energy sustainability. Most times, potential investors in this area show interest about understanding the profitability of the business because, the information boosts the confidence of the investors in the project, and gives them the opportunity of making a short and long term plans about the business. The emissions arising from the energy plant is an important aspect of the venture that requires proper attention, otherwise the costs of emission control may consume a greater part of the profit, hence rendering the business un-viable. Nigeria and South Africa (SA) have abundant biomass (e.g. corn cob, sugarcane bagasse, & pine saw dust) coal and tyre that can be used as fuel in an energy plant. A 10 MW CHP plant was fired with coal and biomass, and tyre obtained from Nigeria and South Africa (SA) respectively, at ratios of 1:1, 3:2, and 4:1 to study the emissions and profits in the plant. An empirical model was employed to estimate the annual amount of feedstock and feed rate required for the plant, after which, an artificial neural network (ANN); LevenbergMarquardt algorithm was used to predict the emissions and profits in the plant for 20-year- investment period with feedstock costing (WFC) and without feedstock costing (WOFC). The profit obtained from the South African feedstock, WFC and WOFC; produced about 45.18 % and 36.83 % ($3,900,000.07 and$3,179,184.49) higher profits than the Nigerian feedstock, but the CO, NOX, & SO2 emissions from Nigerian feedstock were lower than that of SA. The findings from this study could be used as a platform for decision making by potential investors and stake-holders, and further research and development in the area

Advances and emerging techniques for energy recovery during absorptive CO2 capture: a review of process and non-process integration-based strategies

Absorptive CO2 Capture (ACC) is widely embraced as a mature technology to mitigate CO2 emission, but it is energy-intensive and expensive to implement on a commercial scale. It is envisaged that energy recovery could be achieved during ACC by synthesizing and integrating a complex network of flexible heat exchangers to transfer as much energy as possible from a set of hot flows to cold flows. This review provides information on the progress made in the development of process and non-process integration-based techniques alongside their benefits for effective energy recovery during ACC. An exposition on the integration of flexible Heat Exchanger Networks (HENs), its synthesis methodologies, and developments for improving energy recovery during ACC is presented. Furthermore, this review highlights the current state of knowledge creation in process integration and ACC, as well as its underpinning principles, challenges, and opportunities to provide a summary and important discussion on current practices in process integration-based strategies for energy recovery. Current opinions on the integration of flexible HENs for energy recovery during ACC are highlighted. The review also presents a proposed roadmap for large-scale energy recovery during ACC, and suggestions on the improvement opportunities for future research and development were provided. Finally, this review revealed that the integration of flexible HENs is a promising technique for energy recovery during ACC. This study will be beneficial to researchers exploring cost-effective methods for designing sustainable energy systems for effective energy recovery.http://www.elsevier.com/locate/rserpm2022Chemical Engineerin

Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa

Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies

Analysis of arterial intimal hyperplasia: review and hypothesis

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: Despite a prodigious investment of funds, we cannot treat or prevent arteriosclerosis and restenosis, particularly its major pathology, arterial intimal hyperplasia. A cornerstone question lies behind all approaches to the disease: what causes the pathology? Hypothesis: I argue that the question itself is misplaced because it implies that intimal hyperplasia is a novel pathological phenomenon caused by new mechanisms. A simple inquiry into arterial morphology shows the opposite is true. The normal multi-layer cellular organization of the tunica intima is identical to that of diseased hyperplasia; it is the standard arterial system design in all placentals at least as large as rabbits, including humans. Formed initially as one-layer endothelium lining, this phenotype can either be maintained or differentiate into a normal multi-layer cellular lining, so striking in its resemblance to diseased hyperplasia that we have to name it "benign intimal hyperplasia". However, normal or "benign " intimal hyperplasia, although microscopically identical to pathology, is a controllable phenotype that rarely compromises blood supply. It is remarkable that each human heart has coronary arteries in which a single-layer endothelium differentiates earl

Evaluation De La Productivited\'une Association Cocotier / Legumineuses Arborees

Une expérimentation d\'association du cocotier (Cocos nucifera L) avec les légumineuses arborées (Acacia auriculiformis et Acacia mangium) a été mise en place sur les sables quaternaires du littoral ivoirien, pour l\'amélioration de la productivité des cocotiers. Les résultats après 7 ans ont montré une amélioration de la teneur en azote des feuilles de cocotier, soit 2,2 % contre 1,62 % pour le traitement témoin, et de la productivité du cocotier de 50 noix par pied et par an contre 17 noix pour le témoin. Quinze ans après la mise en place de cet essai, la teneur en azote des feuilles de cocotiers est de 2 % contre 1,8 % pour le témoin. De même la productivité du cocotier dans les traitements d\'association a été supérieure à celle du témoin : 84 et 68 noix par pied et par an respectivement pour les traitements «cocotier / Acacia auriculiformis» et «cocotier / Acacia mangium» contre 52 noix pour le témoin. Le traitement «cocotier / Acacia. auriculiformis» avec 1135 kg.ha-1.an-1 de coprah a été supérieur au traitement «cocotier / Acacia. mangium» qui n\'a donné que 924. kg.ha-1.an-1.A coconut palm / Acacia auriculiformis and Acacia mangium intercropping trial was set up in order to improve the productivity of the coconut palm. The trial was set up on the quaternary sands of the Ivorian littoral zone. The first results recorded after seven years showed that the intercropping system has increased the nitrogen content in the leaves (2.2 % against 1.62 % for the control), and the yield of the coconut (50 against 17 nuts per palm). Fifteen years later, the nitrogen content of the leaves was 2 % for the intercropping system against 1.8 % for the control. The yield of the coconut palm in the intercropping treatments was higher than the one of the control : 84 and 68 nuts per palm for «coconut palm / Acacia auriculiformis» and coconut palm / Acacia mangium respectively against 52 for the control. The «coconut palm / Acacia auriculiformis» treatment with 1135 kg.ha-1.an-1 of copra has performed better than the «coconut palm / Acacia mangium»; it gave only 924 kg.ha-1.an- 1 of copra. Keywords: cocotier, azote, arbre fixateur, association culturale, sables quaternaires, Côte d\'Ivoire. coconut palm, nitrogen, fixing tree, intercropping, sandy soils.Agronomie Africaine Vol. 15 (2) 2003: pp. 51-6

Hepatitis B virus prevalence and vaccination in men who have sex with men in West Africa (CohMSM ANRS 12324-expertise France)

Background. Although men who have sex with men (MSM) are at high risk of hepatitis B virus (HBV) infection, they do not have access to vaccination in West Africa, which is a highly endemic region. We investigated HBV prevalence and associated factors, as well as acceptability and difficulties of vaccination in MSM enrolled in an operational research program in Burkina Faso, Cote d'Ivoire, Mali, and Togo. Methods. We followed up 779 MSM in 2015-2018. Participants who were negative for both hepatitis B surface antigen (HBsAg) and antibodies (anti-HBs) at enrollment were offered HBV vaccination. Factors associated with HBV infection were identified using logistic regression models. Results. Overall, HBV prevalence was 11.2% (95% confidence interval [CI], 9.0%-13.6%). It was lower in Togo than in Cote d'Ivoire (2.7% vs 17.3%; adjusted odds ratio [aOR], 0.12; 95% CI, 0.02-0.28) and higher in participants with 6+ recent male sexual partners (21.0% vs 9.3%; aOR, 1.48; 95% CI, 1.12-1.97). Of 528 participants eligible for vaccination, 484 (91.7%) were willing to be vaccinated and received at least 1 dose (ranging from 68.2% in Abidjan to 96.4% in Bamako; P < .001). Of the latter, 390 (80.6%) received 3 or 4 doses. The proportion of participants for whom the minimum required time between each dose was respected ranged from 10.9% in Bamako to 88.6% in Lome (P < .001). Conclusions. MSM in West Africa should be targeted more for HBV screening and vaccination. Although vaccination is well accepted by MSM, greater training of health care workers and education of MSM are required

Taking empowerment into account : the response of community-based organisations to the HIV care needs of men who have sex with men in West Africa (CohMSM ANRS 12324-Expertise France)

Empowerment is an ongoing process through which individuals and communities appropriate power and acquire the capability to function autonomously. Research on empowerment in men who have sex with men (MSM) is lacking in community-based contexts. We investigated the relationship between willingness to be empowered and HIV care needs in West African MSM accessing community-based organisations' (CBO) services. Fifty-three interviews were administered to HIV-negative MSM participating in the CohMSM study (Mali, Burkina Faso, Cote d'Ivoire, Togo). Five indicators of empowerment were identified from a discourse analysis: (i) motivation to access HIV services, (ii) willingness to improve HIV services, (iii) desire to be involved in new activities, (iv) desire to participate in such services, (v) willingness to collaborate in decision making. Based on these indicators, participants were classified into two profiles: high (19/53, 36%) and low (34/53, 64%) level of willingness to be empowered (HWE, LWE). Using a thematic analysis, HWE participants were focused on collective benefit (preventive follow-up, questions about MSM identity), while LWE participants were centred on individual benefit (medical care). CBOs should consider empowerment as a tool to advance collective health benefits for MSM. To improve empowerment in MSM, specific training on issues regarding sexual identity and stigma is needed for CBO providers