Refereed Journals

Remote-sensing products provide opportunities to monitor complex phenomena on the Earth from space for good decision-making. An example is land-cover maps, which are useful for monitoring both human- and naturally induced environmental changes to enhance environmental management for the benefit of the society. Yet there are numerous critical areas of the world such as biodiversity hotspots where the inaccessibility of quality satellite images has hindered progress in our understanding and management of the natural environment. The West African biodiversity hotspot is one such area where persistent thick clouds in freely available satellite images has been a great discouragement to the production of local land-cover maps to monitor the ongoing deforestation and rapid environmental change. Ghana is a country in West Africa where no land-cover map (except global ones) has been published for over a decade although large tracts of land have been converted from their natural states to agricultural land. In this article, we present 30 m land-cover maps of the country using Landsat 8 images and three popular classifiers – Maximum Likelihood Classifier (MLC), Support Vector Machines (SVMs), and random forest (RF) – for the year 2015. We produced these maps for use in our future biodiversity assessment in the region. An overall accuracy (OA) of 85.5% (kappa = 0.77) was achieved for MLC, with similar but slightly lower accuracies for RF and SVM, which indicates that advanced classification algorithms may not have many advantages when applied to process only multispectral optical data. We observe that shrublands, croplands, and orchards are the dominant classes occupying 35.6%, 31.9%, and 18.4% of the country’s land area, respectively. This further indicates that 50.0% of the country’s land area is under agriculture. Thick forests occupy only 8.0% of the land and are almost entirely confined to forest reserves, highlighting the usefulness of these nature reserves. Our maps will provide input for research advancement, policy formulation, and environmental management at both national and subnational levels.

The Ghanaian clay was calcined at temperatures of 600, 700, 800, 900, and 1000°C (1112, 1292, 1472, 1652, and 1832°F) in a laboratory furnace. The properties of the raw and calcined clay were characterized using thermal gravimetric analysis (TGA), 27Al and 29Si solid-state magic angle spinning nuclear magnetic resonance (SS MAS NMR), and Fourier transformed infrared (FTIR) spectroscopic techniques. Pozzolanic strength activity indexes (PSAIs) were determined by replacing portland cement with 20% of the calcined materials.

This paper forms part of research to solve two main problems in Ghana: firstly, the management of municipal solid waste (MSW), particularly with regards to used plastics which have overwhelmed major cities and towns; secondly, the formation of potholes onroads due to excessive traffic and axle weight. This study examines the effect of blending waste thermoplastic polymers, namely High density polyethylene (HDPE) and Polypropyl- ene (PP) in Conventional AC-20 graded bitumen, at various plastic compositions. The plastics were shredded and blended with the bitumen ‘in situ’, with a shear mixer at a temperature range of 160
C–170
C. Basic rheological parameters such as penetration, ring & ball softening point and viscosity tests were employed to determine the resulting changes from base bitumen.FTIR spectroscopy was also employed to study the chemical functionalities present in the bitumen composite. The properties of the unmodified bitumen were found to be enhanced with the changes recorded in the rheological properties of the polymer modified bitumen (PMB). It was observed that polypropylene polymer, showed profound effect on homogeneity and compatibility with slight linear increment in the viscosity, softening and penetration values as against relatively high changes for HDPE modified bitumen.The viscosity of unmodified bitumen was enhanced with the addition of the polymers and thixotropic effect was observed for both HDPE and PP at 60
C. For all modified binders prepared, the penetration values decrease as polymer- bitumen ratio increases whiles softening temperature generally increases as polymer ratio increases. The most compatible and incompatible blends for HDPE were respectively observed at 2% and 3% polymer loading. The most enhanced, homogenous blend is achieved with PP at 3% polymer loading. Three prominent peaks were identified in the spectrum of the unmodified bitumen, occurring at the 3000–2850 cm1 IR frequency range, typical of aliphatic CH symmetrical and asymmetrical stretches in alkanes. CH2 and CH3 bends were also observed at the characteristic frequencies of 1465 cm1 and 1375 cm1 respectively. A low intensity peak was observed within the 2400 cm1–2100 cm1 range, indicating the presence of a very weak CRC- or CRN group with an absorbance of precisely 0.12.The use of waste commodity plastics in binder modification carries the advantage of a cheap and effective means of enhancing conventional bitumen binder performance characteristics and is an alternative way to utilise plastic waste.

Building professionals are now confronted everywhere on green building and construction. Ghana as a lower middle-income country is grappled with a huge housing demand giving rise to a thriving real estate sector in the capital city.