Stratospheric Ozone Trends over the Tropics

The study of the variability and seasonality of ozone over the tropics was carried out between the regions spreading from Latitude 300 South to 300 North. The region was divided into twelve zones of 50 latitudes each, that is, Latitude 0-50 South, 0-50 North,5– 100South and 5– 100 North etc. Secondary data from satellite for each zone was studied both individually and collectively for the period of 1997 to 1999. The results of the statistical analysis indicated that there was seasonality in time of occurrence of maximum and minimum ozone concentration in the tropics. In the northern zones where Nigeria fell, the period of maximum concentration appeared to conincide with the raining season while the minimum with the dry season. The variability of ozone was found to be higher in the high tropical latitudes than around the equato

On utilization of elliptical rings in assessing cracking tendency of concrete

A new experimental method by utilizing elliptical rings to replace circular rings recommended by ASTM and AASHTO was explored for assessing cracking potential of concrete and other cement-based materials under restrained condition. A series of thin and thick elliptical concrete rings were tested alongside circular ones until cracking. Cracking age, position, and propagation were carefully examined. It is found that thin elliptical rings with appropriate geometry can initiate cracks quicker than circular ones, which is desirable for accelerating the ring test. However, thick elliptical rings seem not to exhibit a desirable geometry effect of accelerating ring test compared with circular ones. There were multiple visible cracks that occurred in an elliptical ring and some cracks were initiated but did not propagate through the ring wall. In comparison, there was only one crack in the circular rings. Finally, the features of multiple cracks in restrained elliptical rings were examined and their impact on interpreting elliptical ring test results was elaborated. © 2014 4th International Conference on the Durability of Concrete Structures

Perception of Employers' in Transforming Technical and Vocational Education and Training vis-a-vis Emerging Technology Tools for Sustainable Workforce Development in Nigeria

Economic competitiveness of a country depends to a large extent on the skills of its workforce. The skills and the competencies of the workforce, in turn, are dependent upon the quality of the country’s education and training. Education and training are undergoing continuous change, and this change poses more challenges to the 21st-century workforce, and to training institutions. Despite the importance of TVET in transforming economic development, of any nation, Nigeria still has different perspectives about the competency of its TVET graduates. Therefore, the paper aims at determining the perceptions of Organized Private Sector (OPS) employers’ regarding the competency of TVET graduates and the role of emerging technology tools in transforming TVET for a sustainable workforce development. Using a descriptive survey research design and a sample of 80 OPS employers. A validated and piloted questionnaire based on a 5-point Likert scale used as the data collection instrument for the study. Data were analysed using descriptive and inferential statistics including means, standard deviation and ANOVA. Data analysis was facilitated using the Statistical Package for Social Sciences (SPSS). Findings revealed that employers were not satisfied with the competency level of TVET graduates as it is showed that they are not well prepared to enter the competitive workforce and to be self-reliant. Given the nature and complexity of the field of TVET for a sustainable workforce, it was recommended that the utilization of adequate planning and management of emerging technology tools and resources in teaching TVET programs could contribute enormously to the quality and sustainability of the Nigerian workforce

Computational Quantum Study of Intermediates Formed During the Partial Oxidation of Melatonin

Melatonin is a neurohormone produced by the pineal gland in the brain. It functions as an antioxidant to scavenge free radicals. Free radicals are reactive species; they often oxidize the cells leading to oxidative stress which may lead to severe health complications. Reaction of melatonin with free radicals is known to be stepwise, as such the stability of the intermediates can be examined. Thus, the possibility of using melatonin as an in vivo spin trap can be determined. Spin traps allow characterization of unstable radical species using electron spin resonance spectroscopy. In this research, ab initio quantum chemistry techniques were used to calculate the energies of selected intermediates formed during the partial oxidation of melatonin by hydroxyl radical. Specifically, optimized geometries for melatonin, and selected intermediates with ·OH were obtained at the DFT/B3LYP/cc-pVXZ and HF/cc-pVXZ (X = D, T, Q) levels of theory. Extrapolations to the complete basis set limit were also performed

Impact of Exchange Rate Regimes on Economic Integration in the ECOWAS (1980-2017)

The study investigated the impact of exchange rate regimes on economic integration in the ECOWAS from 1980 to 2015. Secondary annual data were used for the study. Annual data on variables such as trade openness, real gross domestic product, per capita income, transport cost, common language, tariff and exchange rate covering the period from 1980 to 2018 were sourced from the World Development Indicators (WDI) of the World Bank, 2017 edition. Data collected were analysed using econometrics technique of panel panel fixed effect model. The study found that the coefficients of per capita income, transport cost, common language and exchange rate regimes have positive and significant effect on economic integration in the ECOWAS while coefficients of real gross domestic product and tariff have a negative effect of economic integration in the ECOWAS.  The result implies that a unit increase in exchange rate regimes will lead to 0.13% deepening of the economic integration in the ECOWAS. The study concluded that exchange rate regimes plays an important role in promoting economic integration in the ECOWAS.  

Energy potential of yam and plantain peels

    Peels are the wastes produced when yam and plantain are processed for human consumption.  This study evaluated the potential use of these wastes as energy feedstocks by conducting thermal decomposition studies in a thermogravimetric analyzer coupled to a Fourier Transform infrared spectrometer (FTIR) and in a differential scanning calorimeter.  The peels have ash contents of about 8%-9% hence a slightly lower energy contents in comparison to other biomass feedstocks.  The pyrolysis process for both yam and plantain peels was found to consist of two main stages - moisture loss at temperatures less than 150oC, and decomposition of the dry matter component that peaked at temperature of 300oC.  Both samples reached exothermic reactions that also peaked at 300oC.  Based on FTIR analysis, the major gases that evolved during pyrolysis were carbon dioxide, carbon monoxide, acetic acid, methane, methyl isocyanate and ethanol.   Keywords: thermal decomposition, syngas, waste, differential scanning calorimetry, Fourier transform infrared spectroscopy, thermogravimetric analyze

ENHANCING JOB SATISFACTION THROUGH VESTIBULE TRAINING IN CONSTRUCTION INDUSTRIES IN LAGOS STATE

Training of workforce for skill development, productivity enhancement, and improved quality of work is crucial to the attainment of industrial goals and objectives. Such objectives become possible when workers are regularly trained and satisfied with their job. Training is undergoing continuous change, and this change poses challenges to construction industries. Despite the laudable role of training in job performance and satisfaction, construction industries are still having different perspectives on the training of craftsmen. Therefore, this paper aimed at investigating the perception of craftsmen on enhancing job satisfaction through vestibule training in construction industries in Lagos State using an exploratory survey research type of the ex-post facto design. The sample consisted of 108 craftsmen. A validated and piloted questionnaire based on a 4-point rating scale was used for data collection in the study. Data were analyzed using descriptive and inferential statistics including frequency, percentage, means, standard deviation, and ANOVA. Data analysis was facilitated using the Statistical Package for Social Sciences (SPSS). Findings revealed that craftsmen were satisfied with the use of vestibule training as it increases job performance and increases efficiency. It was recommended that construction industries should be given more attention to use vestibule training as a technique of showing trainees how to do a job and then allowing them to get on with the job

Fault Recovery in Swarm Robotics Systems using Learning Algorithms

When faults occur in swarm robotic systems they can have a detrimental effect on collective behaviours, to the point that failed individuals may jeopardise the swarm's ability to complete its task. Although fault tolerance is a desirable property of swarm robotic systems, fault recovery mechanisms have not yet been thoroughly explored. Individual robots may suffer a variety of faults, which will affect collective behaviours in different ways, therefore a recovery process is required that can cope with many different failure scenarios. In this thesis, we propose a novel approach for fault recovery in robot swarms that uses Reinforcement Learning and Self-Organising Maps to select the most appropriate recovery strategy for any given scenario. The learning process is evaluated in both centralised and distributed settings. Additionally, we experimentally evaluate the performance of this approach in comparison to random selection of fault recovery strategies, using simulated collective phototaxis, aggregation and foraging tasks as case studies. Our results show that this machine learning approach outperforms random selection, and allows swarm robotic systems to recover from faults that would otherwise prevent the swarm from completing its mission. This work builds upon existing research in fault detection and diagnosis in robot swarms, with the aim of creating a fully fault-tolerant swarm capable of long-term autonomy

AN INVESTIGATION INTO THE USAGE OF LEAN CONSTRUCTION TECHNIQUES IN NIGERIA

Inadequate implementation of lean construction techniques poses a serious problem to the Nigerian construction process. The usage of lean techniques at the early stage of construction projects results in enhanced environmental performance, waste reduction, an increase in profits, and sustainable construction, among other things. This study focuses on the implementation of lean techniques, with a view to enhancing their usage, thereby improving the performance of construction projects. It examines the lean construction techniques that are used, as well as the extent of their usage, the implementation processes that are used, the benefits of improving usage of lean construction techniques in the study area, and the measures used to improve implementation of such techniques. In achieving these objectives, construction professionals from 10 organisations in Lagos State, Nigeria, were interviewed on 12 selected lean techniques. The data were analysed using descriptive statistics tools, namely means, frequencies, percentages, and modes. The findings reveal that fail-safe quality and safety, daily huddle meetings, increased visualisation, and the 5S process are poorly used, while the other eight techniques, namely Last Planner® System (LPS®), first-run studies, just-in-time (JIT), total production maintenance, concurrent design, kaizen, design for buildability, and supply chain management, are not used at all. Nevertheless, application of the aforementioned first four techniques has contributed to improved workflow on sites, maintenance of good site organisation, and increased job satisfaction among employees. It is recommended that top management, professional bodies, and institutions of higher learning make it a priority to offer education and training programmes on the concept of lean for workers on construction projects. Government should promote the concept of lean techniques, so as to encourage a culture of safety and improve productivity and performance on construction projects