Assessment of carbon Monoxide levels in a commercial district of Akure, Nigeria

The importance of having acceptable indoor environmental quality in building interiors have been well established in rating systems like BREEAM and LEED. However, in a developing nation like Nigeria, where rating systems are under consideration and adequate provision for power is a challenge, retailers in commercial buildings tend to provide power generating sets on their own, more so the influence of vehicular traffic on indoor environment is also of concern to researchers. In the development of a green building rating system for Nigeria, models need to be developed as to the patterns of carbon monoxide (CO) levels in commercial buildings in the country. The purpose of the quantitative study is to assess the level of CO in the terraces of buildings in the Obanla district of Akure in October 2015. Eighty commercial cum residential buildings was assessed in the Ijomu, Obanla commercial axis in Akure, the capital of Ondo State, using dSense Portable CO Meter - a hand held CO monitor, on a once a week measurement, for a month. The implication of increased exposure of CO levels usually from generator fumes and vehicular traffic could lead to reduction in the oxygen carrying capacity of the blood. Results show that the average one hour measurements for eighty positions were 1.225ppm for week one, 1.775ppm for week two, 1.475ppm for week three and 4ppm for week four. These average levels are lower than the WHO indoor air requirement of 30ppm for 1 hour and the USEPA (NAAQS) 35ppm outdoor air 1 hour average

Progress and challenges of demand-led co-produced sub-seasonal-to-seasonal (S2S) climate forecasts in Nigeria

This paper identifies fundamental issues which prevent the effective uptake of climate information services in Nigeria. We propose solutions which involve the extension of short-range (1 to 5 days) forecasts beyond that of medium-range (7 to 15 days) timescales through the operational use of current forecast data as well as improve collaboration and communication with forecast users. Using newly available data to provide seamless operational forecasts from short-term to sub-seasonal timescales, we examine evidence to determine if effective demand-led sub-seasonal-to-seasonal (S2S) climate forecasts can be co-produced. This evidence involves: itemization of forecast products delivered to stakeholders, with their development methodology; enumeration of inferences of forecast products and their influences on decisions taken by stakeholders; user-focused discussions of improvements on co-produced products; and the methods of evaluating the performance of the forecast products. We find that extending the production pipeline of short-range forecast timescales beyond the medium-range, such that the medium-range forecast timescales can be fed into existing tools for applying short-range forecasts, assisted in mitigating the risks of sub-seasonal climate variability on socio-economic activities in Nigeria. We also find that enhancing of collaboration and communication channels between the producers and the forecast product users helps to: enhance the development of user-tailored impact-based forecasts; increases users’ trusts in the forecasts; and, seamlessly improves forecast evaluations. In general, these measures lead to more smooth delivery and increase in uptake of climate information services in Nigeria

Correlation of Global Solar Irradiance with some Meteorological Parameters and Validation of some Existing Solar Radiation Models with Measured Data Over Selected Climatic Zones In Nigeria.

Fourteen models comprising of 12 existing and 2 parameterized models are evaluated for predicting the global solar irradiance on a horizontal surface at six different sites representative of six different climatic zones of Nigeria namely; Mangrove swamp forest (Calabar), Sahel Savannah (Nguru), Montane Vegetation (Yola), Sudan Savannah (Kano), Tropical rain forest (Ibadan) and Guinea Savannah (Minna). Results showed that the two models from this study performed well in predicting global solar irradiance over the six different zones with slight overestimation in some cases and slight underestimation in others. However, out of the two models, model 14 had a better predictive ability. For the 12 existing models, Glover and mcCulloch model was found to be most suitable for the Mangrove swamp forest, Sahel and Montane zones while Raja and Twidell , Rietveld and Annandale et al models are respectively the most suitable models in the Sudan, Tropical rainforest and Guinea zones

Mechanically Reconfigurable Materials and Devices based on Two-dimensional Transition Metal Dichalcogenide Layers

The recent advances in electronic technologies are geared towards a combination of continued miniaturization in device components and their integration onto unconventional platforms. These efforts are aimed towards achieving electronic devices with various form factors and novel functionalities which are unattainable from traditional devices. Among these envisioned \u27futuristic\u27 technologies, electronic devices which are mechanically reconfigurable and operable under harsh operational conditions in the form of stretching, twisting and folding offer tremendous amount of unparalleled opportunities. This dissertation studies two-dimensional (2D) transition metal dichalcogenide (TMDs), a distinct class of materials with peculiar optical, electrical and mechanical properties for mechanically reconfigurable electronics. Owing to their two-dimensional geometry, hence small thickness and extremely large mechanical tolerance, they offer a unique set of advantages unattainable with conventional three-dimensional silicon (Si). We used a novel chemical vapor deposition (CVD) technique to synthesize large-area ( \u3e cm2) 2D TMDs of different compositions onto various rigid and polymeric substrates. Additionally, we developed viable green transfer approached based on water to integrated them onto secondary target substrates, further extending their applicability. In particular, we configured viable strain-engineering concepts to three-dimensionally architect 2D TMD layers into tailored geometries, which can ensure high mechanical stability accompanying well preserved and tunable electrical/optical properties. Moreover, we investigated the strain variable and invariable electrical, optical, mechanical, and structural properties of these materials, explained using simulations and experimental demonstrations. Finally, by combining the novel synthetic and transfer techniques with strain engineered 2D-3D modulations of the TMD layers, we demonstrated several applications of 2D TMDs for futuristic electronics, including ultra-stretchable conductors and transistors for electronic components, wearable heaters and smart tattoos for healthcare, transparent conductors for smart windows, and electromechanical actuators for soft robotics. These studies are part of a new paradigm shift using creative growth and patterning techniques for the development of uniquely mechanically reconfigurable devices

Centimeter-Scale Periodically Corrugated Few-Layer 2D Mos2 With Tensile Stretch-Driven Tunable Multifunctionalities

Two-dimensional (2D) transition metal dichalcogenide (TMD) layers exhibit superior optical, electrical, and structural properties unattainable in any traditional materials. Many of these properties are known to be controllable via external mechanical inputs, benefiting from their extremely small thickness coupled with large in-plane strain limits. However, realization of such mechanically driven tunability often demands highly complicated engineering of 2D TMD layer structures, which is difficult to achieve on a large wafer scale in a controlled manner. Herein, we explore centimeter-scale periodically corrugated 2D TMDs, particularly 2D molybdenum disulfide (MoS2), and report their mechanically tunable multifunctionalities. We developed a water-assisted process to homogeneously integrate few layers of 2D MoS2 on three-dimensionally corrugated elastomeric substrates on a large area (\u3e2 cm2). The evolution of electrical, optical, and structural properties in these three-dimensionally corrugated 2D MoS2 layers was systematically studied under controlled tensile stretch. We identified that they present excellent electrical conductivity and photoresponsiveness as well as systematically tunable surface wettability and optical absorbance even under significant mechanical deformation. These novel three-dimensionally structured 2D materials are believed to offer exciting opportunities for large-scale, mechanically deformable devices of various form factors and unprecedented multifunctionalities

SPATIO-TEMPORAL TREND OF VEGETATION COVER OVER ABUJA USING LANDSAT DATASETS

Vegetation cover has acted as a source of carbon sinks and air purifier for a long period of time especially in developed cities thereby affecting the global climate change. The study was conducted to spatially estimate the Normalized Difference Vegetative Index (NDVI) which is a vegetation indicator for a period of 28 epoch years for Abuja from 1987 to 2014. The positive signatures of NDVI decrease from 2009 to 2014. Statistical analysis of the observed data samples at 95% confidence interval revealed that the changes observed in Year 2009 contributed most to the changes that was occurred in Year 2014.The modeled NDVI values for the year 2014 based on the regression analysis of the previous three years shows a significant agreement between the simulated values for year 2014 and the observed values. In general, there has been fast transformation of the vegetation cover to other land uses. The study reveals vegetation cover had reduced more significantly. It is also worthy to know that the model generated in this research can be used to predict future changes and trends in the vegetation cover. This will provide policy makers with useful information for the proper planning and design of the city and other capital cities over West Africa