Yazar "Mahmoud, Abubakar Sadiq" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Carbon dioxide-assisted Torrefaction of Maize Cobs by Thermogravimetry: Product Yield and Energy Recovery Potentials(VASYL STEFANYK PRECARPATHIAN NATL UNIV, VUL SHEVCHENKA 57, IVANO-FRANKIVSK 76018, UKRAINE, 2022) Nyakuma, Bemgba Bevan; Ajibade, Samuel-Soma M.; Adebayo, Victor B.; Alkali, Habib; Otitolaiye, Victor Olabode; Audu, Jemilatu Omuwa; Bashir, Faizah Mohammed; Dodo, Yakubu Aminu; Mahmoud, Abubakar Sadiq; Oladokun, OlagokeThe objective of this study is to examine the potential product yields and energy recovery of maize cobs (MC) through carbon dioxide-assisted torrefaction using thermogravimetric analysis (TGA). The CO2-assisted torrefaction of MC was performed from 240 °C to 300 °C (? 30 °C) for the residence time of 30 minutes based on the selected non-isothermal/isothermal heating programme of the TGA. Furthermore, the physicochemical, microstructure and mineral characteristics of MC were examined. The results showed that the CO2-torrefaction of MC resulted in mass loss (ML) ranging from 18.45% to 55.17%, which resulted in the mass yield (MY) ranging from 81.55% to 44.83%. The HHV of the solid product was in the range from 22.55 MJ/kg to 26 MJ/kg, which indicates the CO2-torrefaction process enhanced the energy content of MC by 40% – 60%. In conclusion, the findings showed that the CO2 torrefaction is a practical, sustainable, and cost-effective approach for the valorisation of MC into a clean solid biofuel for enhanced energy recovery.Öğe Climate Change Adaptation and Mitigation in Sub-Saharan African Countries(Springer, 2021) Adenuga, Kayode I.; Mahmoud, Abubakar Sadiq; Dodo, Yakubu Aminu; Albert, Moutlen; Kori, Said Alkali; Danlami, Nusa JibrilThe impact of climate change and global warming is high on agriculture, food security, quality of life, human health, economic growth, and development in sub-Saharan African countries. Thus, there are ongoing global discussions on climate change adaptation and mitigation including the Kyoto Protocol; an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions caused by global warming, the 2012 Doha Amendment to the Kyoto Protocol, United Nations Development Programme climate change portfolio, United Nations Educational Scientific and Cultural Organization climate change awareness program, United Nations Environment Programme (UNEP) and other bodies efforts to reduce climate pollutants globally, Africa in particular. However, despite these interventions, there is little scholarly information discussing the extent to which the region’s vulnerability to climate change on its economies and growing populations is addressed. Thus, this review paper examines the impacts of climate change and global warming in sub-Saharan African countries and strategies adopted to mitigate the effects on its environments and economy. © 2021, Springer Nature Switzerland AG.Öğe Key Performance Indicators (KPIs) to Promote Building Developers Safety Performance in the Construction Industry(OMNIASCIENCE, TERRASSA, BARCELONA 00000, SPAIN, 2020) Mahmoud, Abubakar Sadiq; Ahmad, Mohd Hamdan; Yatim, Yahya Mohd; Dodo, Yakubu AminuPurpose: The aim of this study is to establish key performance indicators (KPIs) that can be deployed in the evaluation and promotion of safety performance of building developer’s in Nigeria. Design/methodology/approach: A thorough review of the literature was performed to generally identify sets of KPIs used to evaluate the safety performances of building developer’s during construction. Interviews and focus group discussions were conducted with eleven (11) subject matter experts and professionals to ensure inclusion, validation and clarity of the indicators and to further provide agreement/disagreement, and importance ratings for the identified KPIs. The KPIs was grouped into appropriate categories, keeping out redundant KPIs, and ensuring KPIs are clear and measurable. The Relative Importance Index (RII) and Mean values were computed. Findings: Results from the study consist of 137 KPIs, grouped into 9 categories including: Planning, design and procurement, communication on & maintenance of effective safety behaviour, construction safety policy, construction safety personnel, management effort and support, safety training and enlightenment, administration of safety processes, investigation and reporting of accidents, and rewards and sanctions for project stakeholders. These KPIs were observed to be at different levels of importance from the respondents. The following KPIs were considered based on their extreme importance judging from the respective RII values: communicating safety requirements to designer (98.18%), safety performance set as part of contractor selection criterion (96.36%), availability and accessibility of the relevant insurance policies (98.18%) and appropriate issuance of motivational directives by the top management (100%). Originality/value: Many studies have been done in the past where KPIs as it relates to construction safety were identified. However, the specificity of these KPIs to countries other than Nigeria requires similar research be conducted to identify building developer safety performance KPIs for the Nigerian construction industry.Öğe Safety performance framework at construction site for self-regulation by building developers(Emerald Group Publishing Ltd, 2022) Mahmoud, Abubakar Sadiq; Hamdan Ahmad, Mohd; Mohd Yatim, Yahya; Aminu Dodo, YakubuPurpose This study proposes a self-regulatory framework to enhance safety performance at the construction stage among building developers. Design/methodology/approach Extant literature identified 137 potential factors that influence the construction safety performances of building developers. Focus group discussions and interviews were conducted with 11 panels of experts and professionals. The Relative Importance Index (RII) was used to analyse the response feedback described in a similar paper. In this study, the survey tool used was set up with 40 variables grouped into eight latent variables in the framework, which were agreed and certified as extremely important by the panel. Based on random sampling, data were collected from 229 valid respondents. Structural equation modelling (SEM) technique using Smart PLS software was then used to analyse the respondent's feedback. Findings The results show that safety administration and processes, effective communication of safety behaviour, significantly influenced safety performance on a construction site with beta values of 0.330 and 0.431 along with t values of 3.005 and 2.547 at p < 0.1, respectively. These factors, among others, provide a distinct approach to understanding and improving on-site construction safety. The study findings will potentially benefit building professionals and other stakeholders by improving awareness of safety practices. Research limitations/implications The study may not have covered all possible factors that influence the construction safety performance of building developers. Also, the generalizability and transferability of the research outcome to the construction industry wide use is also limited when reference is made to the characteristics of the research respondents and/or participants. In addition, validation of the framework by five professionals is rather small. Practical implications Theoretically, the framework through the identified factors provide a distinct approach to understanding and improving on-site construction safety through voluntary adherence to self-regulatory standard where there are no enforceable laws and regulations to promote safety. The study findings will potentially benefit building professionals and other stakeholders by improving awareness of the health and safety practices of the construction industry. Originality/value Many research efforts have developed frameworks and models for construction safety. However, the particularity of these frameworks to countries other than Nigeria requires similar research to be conducted to enhance the safety performance of building developers.Öğe Thermogravimetric Study of Maize Cob Carbonization for Bioenergy Recovery: Product Yield Estimation and Bio-Energy Potentials(Slovnaft VURUP a.s, 2021) Otitolaiye, Victor Olabode; Ojomoh, Victor Kayode; Mahmoud, Abubakar Sadiq; Bashir, Faizah Mohammed; Audu, Jemilatu Omuwa; Dodo, Yakubu AminuThe study investigated the bulk fuel, microstructure, morphological, mineral, and functional group characteristics of maize cobs (MC) along with carbonization through thermogravimetric analysis (TGA) for potential energy recovery. To the best of the authors’ knowledge, this is the first study on the micro-scale analysis of the fuel properties and bioenergy recovery potential of MC in the scientific literature. The results showed that MC contains high carbon, hydrogen, oxygen, volatile matter and fixed carbon but low moisture, and ash contents. The functional group (FTIR) analysis revealed MC contains alcohol, ester, and carbonyl functional groups in its chemical structure, which could be attributed to the lignocellulose components of biomass. The analysis of MC microstructure and morphology showed a rough yet compact surface comprising fibres. The TGA carbonisation process revealed MC experienced significant mass loss (ML) ranging from 73–76%, whereas the residual mass or mass yield (RM or MY) was from 23.6–27.2% with increasing carbonisation temperatures from 450–650°C. Furthermore, the findings indicated that the optimal temperature for carbonization of MC is 550°C, based on the conditions examined in this study. The HHV of the solid MY ranged from 26.66 – 26.99 MJ/kg, whereas the energy yield (DE) was 95.42 – 95.63%, and energy density (DE) 3.52 – 4.04. The findings indicate that while the HHV and EY increased, the MY and EY decreased with increasing carbonisation temperatures. In general, the study demonstrated that MC is a potentially suitable raw material or biomass feedstock for the sustainable recovery of bioenergy through carbonization. © 2021. All Rights Reserved.
