Research Articles (Environmental Science)

Permanent URI for this collectionhttps://hdl.handle.net/10413/9330

Browse

Now showing 1 - 10 of 10

Experimental optimization of nanostructured nickel oxide deposited by spray pyrolysis for solar cells application.
(Research India Publications., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.; Eloka-Eboka, Andrew Chukwudum.
This study focused on the experimental optimization of nanostructured nickel oxide (NiO) for solar cell applications. The optimization procedure involved the variation of the precursor concentrations of nickel acetate with attendant measurement of the properties of nickel oxide films. The films were spray deposited on glass substrate. Nickel acetate precursor was used at a substrate temperature of 350 oC. Precursor concentrations were: 0.025 M, 0.05 M, 0.075 M and 0.1 M respectively. The surface morphology revealed nanostructured film with particles densely distributed across the substrate’s surface. The films are homogeneous, smooth, well adherent and devoid of pinholes and cracks. The morphology became grainier as the precursor solution increased. Elemental composition exposes the presence of Ni and O elements in NiO film. Oxygen concentration decreases as precursor solution increases. The film structural property reveals that deposited NiO film has an amorphous structure at 0.025 M while the other concentrations are polycrystalline in nature with cubic structure. X-ray diffractometry (XRD) further reveals that the intensity of NiO films increases with increased molarity. Preferred orientation was along the (1 1 1) peak with minor intensity along the (2 0 0) peak. XRD patterns have peak diffraction at (2θ = 37 o and 43 o) for the (1 1 1) and (2 0 0) planes respectively, and 64 o for the (2 2 0) plane for 0.1 M. Crystallite size was obtained at 63.77 nm maximum. Film thickness increased with increasing precursor concentration from 6.277 μm to 11.57 μm. Film micro strain was observed to have compression for all precursor solutions. Optical studies showed that transmittance decreased with increasing concentration from 80 % to 71 %. Optical band gap energy was between 3.94 eV to 3.38 eV as precursor concentration increased, revealing the effect of varied concentrations on NiO film properties. Optimized results obtained are precursors in the development of low cost, efficient, durable solar cell fabrication for developing countries.
Solar cells and global warming reduction.
(Research India Publications., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.
This study proposes one way of addressing the issue of climate change and pollution using solar cells. The quality of life in developing and low-income countries is on the decline because of air pollution. Energy has a role to play in the quality of life and reduction of air pollution especially in those countries. A reduction in the usage of fossil fuels and biomass in these countries will help decrease the air pollution and emissions generated by such energy sources. About 1 million solar lanterns are capable of reducing greenhouse gas emissions by over 30 000 tons. The role of eco-friendly solar cells in elimination of air pollution cannot be overstated.
Modeling of fabricated NiO/TiO2 P-N heterojunction solar cells.
(Research India Publications., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.
This paper reports modelling and theoretical validation of a fabricated NiO/TiO2 P-N heterojunction solar cell. The solar cell equations were modelled and thereafter theoretical validation of the fabricated solar cells was performed. Modelling tools were used to validate the influence of NiO material features such as deposition temperature, voltage and defect densities on the performances of an ITO/TiO2/NiO heterojunction solar cell structure. The working points used included a temperature of 350 oC, illumination of 1000 W/m2 using an AM1.5 lamp, with voltage range of 0 to 1.5 volts. The output gave Voc of 0.1445 V, Jsc of 247.959195E-6 mA/cm2 and FF of 37.87 % and Voc 0.7056 and Jsc 28.366911 mA/cm2 when both contacts were added. This opens a new frontier for modelling of metal oxide based thin film solar cells especially NiO thin film solar cells. These findings enhance the quest to develop affordable and sustainable energy and encourage further research in solar cell technologies in low-income countries.
Influence of concentration on properties of spray deposited nickel oxide films for solar cells.
(Elsevier., 2017) Ukoba, Kingsley Ogheneovo.; Eloka-Eboka, Andrew Chukwudum.; Inambao, Freddie Liswaniso.
Spray pyrolysis technique was used to deposit various concentration of nickel oxide films on glass substrate. The Effect of varying precursor concentration on elemental, morphological and structural properties was investigated on the deposited NiO films. Nickel (II) acetate tetrahydrate precursor was used at substrate temperature of 350 oC. Precursor concentrations were 0.025, 0.05, 0.075 and 0.1 M. Scanning Electron Microscope (SEM) surface morphology revealed nanostructured films with particles densely distributed across substrates surface. Increased in surface grains was observed as the precursor solution increased. Elemental composition of NiO films revealed presence of Ni and O element. There was reduction in oxygen concentration as precursor solution increases. Amorphous structure was observed at concentration of 0.025 M while polycrystalline with cubic structure was observed at higher concentrations. Preferred orientation was along (1 1 1) peak with small intensity along (2 0 0) peak. XRD patterns have peak diffraction at (2θ = 37 o and 43 o) for (1 1 1) and (2 0 0) planes respectively and 64 o for (2 2 0) plane for 0.1 M. Film thickness grew with increase in precursor concentration. Film micro strain was observed to have compression for all precursor solution conspicuously revealing the effect of varied concentration on NiO films properties
Fabrication of affordable and sustainable solar cells using NiO/TiO2 P-N heterojunction.
(Hindawi., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.; Eloka-Eboka, Andrew Chukwudum.
The need for affordable, clean, efficient, and sustainable solar cells informed this study. Metal oxide TiO²/NiO heterojunction solar cells were fabricated using the spray pyrolysis technique. The optoelectronic properties of the heterojunction were determined. The fabricated solar cells exhibit a short-circuit current of 16.8 mA, open-circuit voltage of 350 mV, fill factor of 0.39, and conversion efficiency of 2.30% under 100mW/cm² illumination. This study will help advance the course for the development of low-cost, environmentally friendly, and sustainable solar cell materials from metal oxides.
Rebranding of the Greater St Lucia Wetlands Park in South Africa : reflections on benefits and challenges for the former of St Lucia.
(Kamla-Raj Enterprises., 2013) Chellan, Noel.; Mtshali, Mdu.; Khan, Sultan.
Post-apartheid South Africa has witnessed an explosion of both national and international ecotourism given its many years of restrictions on the movement of people in the past. Much of its biodiversity has been commodified through branding and re-branding in order to capture a fair share of the international ecotourism market. The Greater St Lucia Wetland Park, located in the northern part of KwaZulu-Natal, was the centre of land claim contestations by the local inhabitants who have been removed from the park due to colonial occupation and later apartheid segregation policies. Locals who have been victims of forced removals from the Park staked a claim to be co-consumers of development and financial benefits accruing from this natural asset. Despite many unfinished challenges facing the politics of the Park, in 2007 the Greater St Lucia Wetland Park was re-branded as the iSimangaliso Wetland Park (iSWP) to market it as an indigenous and local product. One of the rationales for rebranding was the assumption that its previous name competed against another international tourist destination located in the Caribbean. Given the multi-faceted nature of the Wetland Park as a place product, the paper tests out the extent to which this re-branding from a globalised to a localised ecotourism name destination has reproduced itself in terms of benefits, both tangibles and intangibles in the all White town of St Lucia.
Participatory risk assessment of tourism development in coastal areas : challenges and implications for management on the KwaZulu-Natal coast.
(Kamla-Raj Enterprises., 2013) Ahmed, Fathima.; Nadasen, Naadira.
Geographic concentration of coastal tourism and its associated development impacts are strongly associated with proximity to the littoral zone. Concurrently, this is an area where normative collaboration, policy and science rarely coincide. Poor understandings of interlinks between coastal ecosystems by both public and private entities has led to short-sighted tourist investment which fails to consider beach capacity or resource constraints. The results are the loss of ecosystem services which critically impair the resilience of coastlines, making them susceptible to natural and climate-related risks. Concerns and contestations over natural resources are entrenched in ecological, economic and social dynamics. However tourism tends to favour the economic, which is inadequate. The potential for high-income, mass and ecotourism is huge along the KwaZulu-Natal coastline which is relatively undeveloped. The objective of this study emphasizes a participatory risk assessment of the tourism sector by interrogating land use-ecology interactions as necessary for optimal relationships between coastal uses and protection of coastal ecosystems. Key findings reveal that there are stressors acting cumulatively on individual ecosystems, thus the need to adopt a strategic view to management. Furthermore, the tourism footprint emerged as being larger than the industry itself, implying the potential benefits of integration across different sectors, stakeholders and legislation along the coast, with regard to tourism and its associated development.
Eco-tourism, conservancies and sustainable development : the case of Zimbabwe.
(Kamla-Raj Enterprises., 2013) Muzvidziwa, Victor Ngonidzashe.
The paper presents a definition of eco-tourism that puts an emphasis on conservation through utilisation, instead of an emphasis on preservation only. Eco-tourism in this paper is seen as incorporating both consumptive and non-consumption aspects. It is a definition that stresses community participation in decision making processes in relation to eco-touristic ventures and subsequent benefits derived from such ventures flowing back to local communities. The paper examines the triple role of eco-tourism in the protection, utilisation and conservation of natural and cultural resources. Tourism is by far a sector that continues to play a positive socioeconomic role in the midst of a declining economic base in the Zimbabwe of the post 2000 period. The paper views conservancies as tenurial units and goes further to examine the link between conservancies and eco-touristic ventures. The issue of sustainable eco-tourism developments in the form of conservancies is debated in the paper in the light of the socio-economic challenges Zimbabwe is going through. It is strongly argued that to avoid another case of entrenched failed development, conservancies need to be seen in a holistic manner that takes into account the role of all stakeholders or actors including the role of local communities.
Tourism impacts on subsistence agriculture : a case study of the Okavango Delta, Botswana.
(Kamla-Raj Enterprises., 2013) Harrison, Phillipa Anne.; Maharaj, Bridgemohan.
The booming tourism industry in the developing countries has been widely viewed as a source of investment, employment and foreign exchange. There is an assumption that the economic benefits of tourism will trickle down to stimulate other sectors of the economy, including agriculture. The government of Botswana, for example, is grappling with the task of developing a tourism policy that will maximize its goals of rural job creation, revenue generation from foreign exchange, conserve and protect wildlife, and be compatible with the cultural norms of its people. As the rural community in the Okavango Delta shifts its focus from agriculture to tourism, several concerns emerge. A key contention of this paper is that a major challenge facing the Okavango Delta region in the twenty first century is an attempt to support the tourism industry without compromising the traditional livelihoods of its local inhabitants. More specifically, as tourism increases economic growth and employment opportunities, it is becoming difficult for local inhabitants to sustain traditional subsistence agricultural livelihoods. As increasing numbers of rural, communal agricultural people migrate to urban areas, the International Union for the Conservation of Nature warned that the uncontrolled expansion of human activities, predominantly associated with tourism, and the foreign control of resources is resulting in the abandonment of many traditional practices, including agriculture, and threatening the livelihoods of the Okavango Delta’s inhabitants. Hence, the Okavango Delta presents a unique opportunity to study the impact of tourism on rural agriculture, to observe the negotiation and competition which occurs between global tourism and local agriculture, and to review the inevitable transformation of local culture, economy and physical landscape.
Mega-events and tourism impacts : foreign visitor perceptions of the 2010 FIFA World Cup in South Africa.
(Kamla-Raj Enterprises., 2013) Bob, Urmilla.; Potgieter, Cheryl.
There are several impacts of hosting events that relate to economic and social development aspects. South Africa has used sport tourism to promote the country as a major sports events destination. Research on mega-events tends to focus on economic impacts, including tourism effects. Very few, however, examine visitor perceptions of the event to establish experiences and concerns. This article examines the positive and negative relationships between tourism and the hosting of mega-events with a special focus on the 2010 FIFA World Cup, Africa’s first mega-event. Additionally, visitor perceptions derived from interviews undertaken with 4 814 foreign tourists during the World Cup are examined. The results reveal that foreign visitors generally enjoyed their stay in South Africa and perceived the country as a good tourism destination. The article concludes that tourism outcomes related to the hosting of mega-events need to be planned, particularly if more widespread benefits are to be realised within the tourism industry and in local communities. In particular, the positive experiences and images of South Africa as a result of the World Cup should be integrated into an appropriate destination marketing strategy.

Browse

Recent Submissions