7 resultados para Tanzania grass
em Aston University Research Archive
Resumo:
Over the last 30 years, the field of problem structuring methods (PSMs) has been pioneered by a handful of 'gurus'—the most visible of whom have contributed other viewpoints to this special issue. As this generation slowly retires, it is opportune to survey the field and their legacy. We focus on the progress the community has made up to 2000, as work that started afterwards is ongoing and its impact on the field will probably only become apparent in 5–10 years time. We believe that up to 2000, research into PSMs was stagnating. We believe that this was partly due to a lack of new researchers penetrating what we call the 'grass-roots community'—the community which takes an active role in developing the theory and application of problem structuring. Evidence for this stagnation (or lack of development) is that, in 2000, many PSMs still relied heavily on the same basic methods proposed by the originators nearly 30 years earlier—perhaps only supporting those methods with computer software as a sign of development. Furthermore, no new methods had been integrated into the literature which suggests that revolutionary development, at least by academics, has stalled. We are pleased to suggest that from papers in this double special issue on PSMs this trend seems over because new authors report new PSMs and extend existing PSMs in new directions. Despite these recent developments of the methods, it is important to examine why this apparent stagnation took place. In the following sections, we identify and elaborate a number of reasons for it. We also consider the trends, challenges and opportunities that the PSM community will continue to face. Our aim is to evaluate the pre-2000 PSM community to encourage its revolutionary development post-2006 and offer directions for the long term sustainability of the field.
Resumo:
Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R2 values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses.
Resumo:
After thirty years of vacillation, the Tanzanian government has made a firm decision to Swahilize its secondary education system. It has also embarked on an ambitious economic and social development programme (Vision 2025) to transform its peasant society into a modern agricultural community. However, there is a faction in Tanzania opposed to Kiswahili as the medium of education. Already many members of the middle and upper class their children to English medium primary schools to avoid the Kiswahili medium public schools and to prepare their children for the English medium secondary system presently in place. Within the education system, particularly at university level, there is a desire to maintain English as the medium of education. English is seen to provide access to the international scientific community, to cutting edge technology and to the global economy. My interest in this conflict of interests stems from several years' experience teaching English to students at Sokoine University of Agriculture. Students specialise in agriculture and are expected to work with the peasant population on graduation. The students experience difficulties studying in English and then find their Kiswahili skills insufficient to explain to farmers the new techniques and technologies that they have studied in English. They are hampered by a complex triglossic situation in which they use their mother tongue with family and friends, Kiswahili, the national language for early education and most public communication within Tanzania, and English for advanced studies. My aim in this thesis was - to study the language policy in Tanzania and see how it is understood and implemented; - to examine the attitudes towards the various languages and their various roles; - to investigate actual language behaviour in Tanzanian higher education. My conclusion is that the dysfunctionality of the present study has to be addressed. Diglossic public life in Tanzania has to be accommodated. The only solution appears to be a compromise, namely a bilingual education system which supports from all cases of society by using Kiswahili, together with an early introduction of English and its promotion as a privileged foreign language, so that Tanzania can continue to develop internally through Kiswahili and at the same time retain access to the globalising world through the medium of English.
Resumo:
Study on Napier grass leaf (NGL), stem (NGS) and leaf and stem (NGT) was carried out. Proximate, ultimate and structural analyses were evaluated. Functional groups and crystalline components in the biomass were examined. Pyrolysis study was conducted in a thermogravimetric analyzer under nitrogen atmosphere of 20 mL/min at constant heating rate of 10 K/min. The results reveal that Napier grass biomass has high volatile matter, higher heating value, high carbon content and lower ash, nitrogen and sulfur contents. Structural analysis shows that the biomass has considerable cellulose and lignin contents which are good candidates for good quality bio-oil production. From the pyrolysis study, degradation of extractives, hemicellulose, cellulose and lignin occurred at temperature around 478, 543, 600 and above 600 K, respectively. Kinetics of the process was evaluated using reaction order model. New equations that described the process were developed using the kinetic parameters and data compared with experimental data. The results of the models fit well to the experimental data. The proposed models may be a reliable means for describing thermal decomposition of lignocellulosic biomass under nitrogen atmosphere at constant heating rate.
Resumo:
Good estimates of ecosystem complexity are essential for a number of ecological tasks: from biodiversity estimation, to forest structure variable retrieval, to feature extraction by edge detection and generation of multifractal surface as neutral models for e.g. feature change assessment. Hence, measuring ecological complexity over space becomes crucial in macroecology and geography. Many geospatial tools have been advocated in spatial ecology to estimate ecosystem complexity and its changes over space and time. Among these tools, free and open source options especially offer opportunities to guarantee the robustness of algorithms and reproducibility. In this paper we will summarize the most straightforward measures of spatial complexity available in the Free and Open Source Software GRASS GIS, relating them to key ecological patterns and processes.
Resumo:
This study presents a report on pyrolysis of Napier grass stem in a fixed bed reactor. The effects of nitrogen flow (20 to 60 mL/min), and reaction temperature (450 to 650 degrees C) were investigated. Increasing the nitrogen flow from 20 to 30 mL/min increased the bio-oil yield and decreased both bio-char and non-condensable gas. 30 mL/min nitrogen flow resulted in optimum bio-oil yield and was used in the subsequent experiments. Reaction temperatures between 450 and 600 degrees C increased the bio-oil yield, with maximum yield of 32.26 wt% at 600 degrees C and a decrease in the corresponding bio-char and non-condensable gas. At 650 degrees C, reductions in the bio-oil and bio-char yields were recorded while the non-condensable gas increased. Water content of the bio-oil decreased with increasing reaction temperature, while density and viscosity increased. The observed pH and higher heating values were between 2.43 to 2.97, and 25.25 to 28.88 MJ/kg, respectively. GC-MS analysis revealed that the oil was made up of highly oxygenated compounds and requires upgrading. The bio-char and non-condensable gas were characterized, and the effect of reaction temperature on the properties was evaluated. Napier grass represents a good source of renewable energy when all pyrolysis products are efficiently utilized.
Resumo:
Purpose – The purpose of this paper is to contribute to the ongoing debate on governance, accountability, transparency and corporate social responsibility (CSR) in the mining sector of a developing country context. It examines the reporting practices of the two largest transnational gold-mining companies in Tanzania in order to draw attention to the role played by local government regulations and advocacy and campaigning by nationally organised non-governmental organisations (NGOs) with respect to promoting corporate social reporting practices. Design/methodology/approach – The paper takes a political economy perspective to consider the serious implications of the neo-liberal ideologies of the global capitalist economy, as manifested in Tanzania’s regulatory framework and in NGO activism, for the corporate disclosure, accountability and responsibility of transnational companies (TNCs). A qualitative field case study methodology is adopted to locate the largely unfamiliar issues of CSR in the Tanzanian mining sector within a more familiar literature on social accounting. Data for the case study were obtained from interviews and from analysis of documents such as annual reports, social responsibility reports, newspapers, NGO reports and other publicly available documents. Findings – Analysis of interviews, press clips and NGO reports draws attention to social and environmental problems in the Tanzanian mining sector, which are arguably linked to the manifestation of the broader crisis of neo-liberal agendas. While these issues have serious impacts on local populations in the mining areas, they often remain invisible in mining companies’ social disclosures. Increasing evidence of social and environmental ills raises serious questions about the effectiveness of the regulatory frameworks, as well as the roles played by NGOs and other pressure groups in Tanzania. Practical implications – By empowering local NGOs through educational, capacity building, technological and other support, NGOs’ advocacy, campaigning and networking with other civil society groups can play a pivotal role in encouraging corporations, especially TNCs, to adopt more socially and environmentally responsible business practices and to adhere to international and local standards, which in turn may help to improve the lives of many poor people living in developing countries in general, and Tanzania in particular. Originality/value – This paper contributes insights from gold-mining activities in Tanzania to the existing literature on CSR in the mining sector. It also contributes to political economy theory by locating CSR reporting within the socio-political and regulatory context in which mining operations take place in Tanzania. It is argued that, for CSR reporting to be effective, robust regulations and enforcement and stronger political pressure must be put in place.