Thermal Comfort and Occupant Behaviour in a Naturally Ventilated Hostel in Warm-Humid Climate of Ile-Ife, Nigeria: Field Study Report during Hot Season

Naturally ventilated buildings have been observed to be ineffective in warm-humid tropical especially during hot season To ascertaining this observation this study presents the results of a short-term thermal comfort survey performed in a naturally ventilated hostel building in Obafemi Awolowo University Ile-Ife Nigeria during hot season Using the data obtained from questionnaire survey and physical measurement of air temperature relative humidity and air velocity using Kestrel model 4500 thermal environmental conditions occupant comfort and adaptation methods were investigated considering class II protocol Ninety six respondents participated in the study Statistical analysis of students responses and measured thermal environmental variables was performed to determine existing indoor environmental conditions and priority of using adaptive controls All the measured environmental variables fell below the comfort range recommended by ASHRAE standard 55 and ISO 7730 standard On the contrary respondents were comfortable preferring cooler no change environments and more air movement First preference of the respondents adaptive control was window opening 77 4 closely followed by wearing light clothes 77 3 and lastly the use of electric fans This study concludes that in warm-humid climate of Ile-Ife during the hot season the desire for sustainable thermal comfort may not be achieved without mechanical ventilation syste

Investigating the applicability of PMVe-PPDe model in non air-conditioned hostel building

To make PMV-PPD model applicable in NV buildings, Fanger proposed PMVe-PPDe model by including an expectancy factor (e). However, there are conflicting reports as regard the applicability of the model in NV buildings. Using the data obtained from physical measurement of (air temperature, relative humidity and air velocity) using Kestrel model 4500, questionnaire survey and observation considering class II protocol, the applicability of PMVe-PPDe model in a NV hostel building was investigated. All the measured environmental variables fell below the comfort range recommended by ASHRAE standard 55 and ISO 7730 standard. Most (85%) of the calculated PMVe values fell within the comfort range recommended by ASHRAE standard 55 and ISO 7730 standard. The obtained PPDe results showed only a slight overestimation (8.9% about) of the percentage of dissatisfied under neutrality conditions. The study concluded that PMVe-PPDe is applicable in NV hostel in this climate. According to the findings of this study, it can be concluded that the Fanger’s basic approach for the assessment of the thermal comfort is effective also in naturally ventilated hostel environments if a right expectancy factor is applied. Keywords: NV environments, thermal comfort in hostel, PMVe-PPDe, expectancy factor

Thermal Comfort and Occupant Behaviour in Naturally Ventilated Students’ Hostel Buildings: A Case of Covenant University, Ota, Nigeria

The performance of a building goes a long way in affecting the productivity and heath of its occupants. Indoor thermal comfort of a building is one of the most important considerations. In warm humid tropical areas, natural ventilation has been observed to be ineffective in providing adequate thermal comfort. The study examined the thermal comfort of naturally ventilated students’ hostel buildings in Covenant University, Ota, Ogun State, Nigeria, during the hot season. The study identified and assessed the physical characteristics, examined the indoor environmental conditions relating to thermal comfort, identified and examined factors that affect the thermal comfort of occupants and observed their adaptive behaviors.The study involved a subjective assessment through questionnaires and physical measurements of the prevailing indoor environmental variables. The parameters measured were air temperature, air velocity and relative humidity. This was done using a Kestrel 4500 Pocket Weather Tracker. One hundred respondents participated in the survey. A statistical analysis of the measured environmental parameters and the student’s responses was carried out to determine the indoor environmental conditions and adaptive measures used. All the measured parameters fell below the comfort range prescribed by ASHRAE standard 55 and ISO 7730 standard. The study concludes that natural ventilation alone is insufficient to provide adequate thermal comfort levels for its occupants

Framework for Efficient Electrical Energy Management Practice in Public Universities in Southwestern Nigeria

Energy management practices are subject to various worries that impact on achieving electricity saving objectives. This is most apparent in the case of Public Universities in Nigeria due to the number of electricity end users with conflicting interests. Efficient electrical energy management in Public Universities in Nigeria becomes crucial. The present work developed a multidimensional framework of efficient electricity management by considering all relevant measures of performance. To achieve the formation of this evaluation framework, it has considered the case of three relatively old public universities and collected the viewpoints of 4728 respondents comprising students, staff, and business owners involved in the aggregate electricity use in Public Universities in Nigeria. We adopted a quantitative survey and questionnaire as instrument for gathering relevant data. The results of the analysis of data obtained during the survey were used to develop the framework by considering key attributes. The study concluded that the formation of the newly-proposed quantitative efficient electricity management framework for improving the energy performance of public university buildings can provide the university management with an effective tool to benchmark with different university buildings internationally and assist the priority setting of efficient electricity savings. Keywords: Framework, Efficiency, electrical energy management, Practice, Public universities, Southwestern Nigeri

Time-Dependent Ginzburg–Landau equation modelling of electron beam additive manufactured Titanium alloy

In this study, the micro-structure evolution in Electron beam additive manufacturing (EBAM) process of Ti–6Al–4V is studied using phase-field modelling. EBAM involves a rapid solidification process and the properties of a build partly depend on the solidification behaviour as well as the micro-structure of the build material. Phasefield modelling was applied to study the evolution of micro-structural scale of dendrites during the Ti-6Al-4V alloy solidification in the EBAM process. The mechanical properties of the final build parts are dependent on the solidification rate which affects the micro-structure of the material. Thus, the evolving of micro-structure plays a critical and effective role towards process parameters optimization. Recent increase in computational power allows for direct simulations of micro-structures during materials processing for specific manufacturing conditions. A MATLAB code was developed to solve the set of Time-Dependent Ginzburg–Landau equation phase field equations. The effect of under-cooling was investigated through the simulations; the greater the under-cooling, the faster the dendrite grows. The micro-structure simulations shows the growth of primary β phase, which has a body-centred cubic crystal structure phase with four fold symmetry comparable with experimental results for the tested range

Inventing a New Africa through Discovery and Innovations in Computational Material Science

Researchers are increasingly relying on computational technologies to help in simulation of properties of new materials and some areas in materials science has enjoyed some level of success which ranges from composites, to polymer science and to advanced ceramics. This review paper discuss certain developments in the area of computational Materials and how Africa can leverage on this technology to develop their emerging Industries, while dwelling more on application of computational material science in energy sector, since energy has been most pressing challenges in Africa which could be addressed by advanced materials. Also, we summarize part of our research work on galvanic corrosion of mild steel bolt in a magnesium alloy (AZ91D) plate simulation using comsol Multiphysics and 2k factorial experiments on factors that influence the recovery of gold during the upgrade of Ilesha-Itagunmodi, Nigeria gold ore through Froth flotation using Anova software. Attempt have been made to identify existing computational method, challenges of computational materials science deployment in Africa, and how material development can be accelerated through the power of computational material science. With this work, we were able to establish that the strength of computational materials science is in making a connection between the experiment and theories of complex phenomena

Inventing a New Africa through Discovery and Innovations in Computational Material Science

Researchers are increasingly relying on computational technologies to help in simulation of properties of new materials and some areas in materials science has enjoyed some level of success which ranges from composites, to polymer science and to advanced ceramics. This review paper discuss certain developments in the area of computational Materials and how Africa can leverage on this technology to develop their emerging Industries, while dwelling more on application of computational material science in energy sector, since energy has been most pressing challenges in Africa which could be addressed by advanced materials. Also, we summarize part of our research work on galvanic corrosion of mild steel bolt in a magnesium alloy (AZ91D) plate simulation using comsol Multiphysics and 2k factorial experiments on factors that influence the recovery of gold during the upgrade of Ilesha-Itagunmodi, Nigeria gold ore through Froth flotation using Anova software. Attempt have been made to identify existing computational method, challenges of computational materials science deployment in Africa, and how material development can be accelerated through the power of computational material science. With this work, we were able to establish that the strength of computational materials science is in making a connection between the experiment and theories of complex phenomena

Critical Success Factors as a Tool for Sustainable Efficient Electricity Management in Nigeria Public Universities

University subsector is one of the fastest-growing electricity consumers in Nigeria and is known to have significant impacts on Nigeria energy mix. Various electricity conservation measures have been adopted for improving efficient electricity use but in terms of sustainability little success has been achieved due to inability to tackle some barriers. Exploring into CSFs has been identified as one of the surest ways of removing barriers towards meeting sustainable efficient energy management and savings in HEIs. Focusing on the importance of practicing energy management effectively, this study developed a set of critical success factors for implementing electricity management in university subsector with emphasis on sustainability. Data for the study were collected from three public universities in Southwestern Nigeria, namely Obafemi Awolowo University, Ile-Ife, University of Ibadan and Federal University of Technology, Akure, to obtain stakeholders’ perspective on the importance of proposed CSFs. The existing 23 CSFs were utilised and evaluated by 4728 experts and users randomly selected from academic office buildings, students’ hostels, staff quarters and business units. The data for the study were collected through a structured questionnaire and were analysed using mean index, factor analysis and logistic binary regression. The results show that all the attributes are significant for achieving sustainable efficient electricity management. The study concluded that achieving sustainable efficient electricity management practice in public universities requires seeking top management support, establishment of comprehensive energy management team and inclusion of stakeholders in energy management of the facility. Keywords: CSFs, Efficient, Electricity, Nigeria, Tool, Sustainable, Universit

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic