Browsing by Author "Rwenyagila, E.R."
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Item Nanostructured TiO2 and their energy applications-a review(ARPN Journal of Engineering and Applied Sciences, 2013-10) Nyankson, E.; Agyei-Tuffour, B.; Asare, J.; Annan, E.; Rwenyagila, E.R.; Konadu, D.S.; Yaya, A.; Dodoo-Arhin, D.Environmental sustainability and reliable energy sources are major challenges facing the world in the 21st century. Ironically, the solution to these taunting problems may lie in something small. Nanomaterials with attractive chemical and physical properties are being explored for potential uses in energy and environmental applications. Nanostructured Titanium dioxide (TiO2) has gained considerable attention in the energy and environment sectors due to their brilliant prospects in photo catalysis, solar cells, environmental pollution treatment and its use in solar water splitting for the production of H2. There are many processing techniques such as; the Sol gel (SG), the hydro-thermal (HT), the solvothermal (ST) and chemical vapor deposition (CVD) which are used in the production of nanostructured TiO2 for the applications stated above. This review aims at examining the general characteristics of nanostructured TiO2 and its application in dye sensitized solar cells, photocatalytic splitting of water and solid state hydrogen storage devices. The analysis is meant to demystify the anxiety associated with the application of nanomaterials in solving everyday challenges in the energy and environmental sectors. © 2006-2013 Asian Research Publishing Network (ARPN).Item Untraditional synthesis of ni-based alloys for medical application(ARPN Journal of Engineering and Applied Sciences, 2013-04) Agyei-Tuffour, B.; Annan, E.; Rwenyagila, E.R.; Ampaw, E.; Arthur, E.; Mustapha, K.; Kolawole, S.; Soboyejo, W.O.; Marinov, M.I.; Radev, D.D.Due to the combination of excellent mechanical properties, high chemical stability and appropriate biocompatibility, the Ni-based alloys find large application in implantology and dentistry. The traditional metallurgical synthesis methods of these alloys have some difficulties leading to inconstancy of the composition, degradation of properties and escalation of the product price. Here we show how to overcome the disadvantages of the traditional methods of synthesis and production of Ni-based alloys for medical application using combination of mechanochemical and powder-metallurgical routes. The structural properties of the products were studied using SEM/TEM and XRD methods. It was shown that the mechanically assisted synthesis allows obtaining nanosized Ni-Ti alloy with mean particle size of 20- 30 nm at significantly lower temperature in comparison with the traditional metallurgical high-temperature alloying. It was also shown that after 40 hours of intense mechanical treatment of the starting Ni and Ti powders, a direct synthesis of Ni- Ti alloy proceeds. The product has excellent sinterability which allows producing bodies with controlled structural properties appropriate for application in implantology. Using standard mechanical tests and structural examinations it was demonstrated that the Ni-Cr dental alloys obtained by mechanically assisted sintering and casting possess excellent mechanical, technological and aesthetic properties. These alloys are suitable as dental restoration materials and production of porcelain veneered constructions like crowns and bridges using the so called metal-to-ceramic technique. © 2006-2013 Asian Research Publishing Network (ARPN).