Nach oben pdf Three-dimensional analysis of syndepositional faulting and synkinematic sedimentation, Niger Delta, Nigeria

Three-dimensional analysis of syndepositional faulting and synkinematic sedimentation, Niger Delta, Nigeria

Three-dimensional analysis of syndepositional faulting and synkinematic sedimentation, Niger Delta, Nigeria

Subsurface geology, data and methodology The Niger Delta is one of the World’s largest Tertiary delta systems, located on the West African continental margin at the apex of the Gulf of Guinea (Fig. 3-2). The delta succession comprises a highly progradational, generally upward-coarsening association of Tertiary clastics up to 12 km thick (Doust and Omatsola, 1989). The delta stratigraphy and structure are intimately related, with the development of each being dependent on the interplay between sediment supply and subsidence (Doust, 1990). The geological analyses presented in this study are based on the interpretation of a pre-stack time migrated 3D seismic-reflection volume of a ca. 400 km² survey area in the coastal-marine transition of the western Niger Delta (Fig. 3-2). The study area is located in the extensional, gravity-driven structural domain of the delta (Doust and Omatsola, 1989; Damuth, 1994; Hooper et al., 2002), in which the progradation of the deltaic sedimentary wedge over basal marine shales caused the formation of numerous kilometre-scale, gravity- driven, syn-sedimentary growth faults (Fig. 3-3; also see Thorsen, 1963; Bruce, 1973; McCulloh, 1988; Lundin, 1992; Cartwright et al., 1998). The northwestern part of the study area is marked by three large-scale, arcuate-shaped, seaward-dipping normal faults (faults 1, 2 and 3) that extend laterally over several kilometers (Fig. 3-3) and displace sedimentary units of Pliocene to recent age by several hundreds of milliseconds TWT (Fig. 3-4 section A). In contrast, the central and southeastern parts of the study area exhibit a structurally complex zone of deltaic rollover (Fig. 3- 4 section B; Fig. 3-5 sections C and D) which is bound on its landward side by a series of large, subparallel, seaward-dipping, highly listric deltaic faults.
Mehr anzeigen

119 Mehr lesen

The impact of poverty, unemployment, inequality, corruption and poor governance on Niger Delta militancy, Boko Haram terrorism and Fulani herdsmen attacks in Nigeria

The impact of poverty, unemployment, inequality, corruption and poor governance on Niger Delta militancy, Boko Haram terrorism and Fulani herdsmen attacks in Nigeria

International Journal of Management, Economics and Social Sciences 62 Brown puts it succinctly (1987, p. 7): “Whatever violates another, in the sense of infringing upon or disregarding or abusing or denying that other, whether physical harm is involved or not, can be understood as an act of violence…. In the broadest sense then, an act that depersonalizes would be an act of violence, since… it transforms a person into a thing”. In other words, violence involves damage to what the victim holds dear. Oby (2001) emphasized that violence and conflict are unavoidable and keep occurring. “Every day, every individual encounters at least two or three conflicts either at home, at work, at social outings or even when a person sleeps in a bedroom without talking to anyone. Therefore, people are no longer new to those things that cause these conflicts, known as sources of conflicts” (Osagie et al., 2010, p. 83). There are different types of conflicts: conflicts over resources, conflicts over psychological needs and conflicts involving values. In Nigeria, conflicts over resources are more common, as when two or more ethnic groups want the same thing e.g., the Niger Delta oil. In such a case, the parties might attack the resources in the heat of the conflict. Conflicts over psychological needs affect the psyche of the individual and its productive capacity. Bur (2001), Owuamanam (2001), and Onuorah (2001) have provided extensive discussions of conflicts.
Mehr anzeigen

24 Mehr lesen

Rural community participation in sustainable management of the Niger delta forests, Nigeria

Rural community participation in sustainable management of the Niger delta forests, Nigeria

ABSTRACT The Niger Delta region has been well-known for its crude oil, which provides over 80% of Nigeria’s annual income and since the 1990s, it has been known for armed conflicts and hostilities. The region is generally under-developed and the environment is being degraded as people try to secure their livelihoods. This thesis aims to identify the ecosystem benefits derived from the Niger Delta environment by local communities; appraise the methods of forest management and their effectiveness to provide a steady flow of the ecosystem benefits; identify stakeholders in the use and management of forest ecosystems, and suggest methods of collaborative forest resources management. The research adopted deductive and inductive social research methods to obtain primary data and was guided by three frameworks: livelihoods, ecosystems services, and the stakeholder participation and analysis. The result showed that the rural dwellers of the Niger Delta depend almost entirely on ecosystem benefits for their survival; they have no access to crude oil but can access forest goods and services. The urban dwellers were aware of the range of provisioning, regulatory, cultural, and supporting services but rural dwellers were mainly only aware of provisioning services. The forest stakeholders were identified to comprise rural dwellers, local NGOs, academic and research institutions (classified as subjects); international agencies such as the UN (classified as key players); wood-based industries and urban dwellers (classified as crowd); and the government and oil exploration companies (classified as context setters). The existing forest management approaches included effective community traditional approaches (where they exist) and government laws and policies establishing forest reserves, which were mainly found to be ineffective. At present, the main forest management approach is top-down and initiated by government. The full cohorts of stakeholders are not working together to ensure the effective management of these resources. This thesis recommends a collaborative forest management approach, which involves identified key stakeholders.
Mehr anzeigen

366 Mehr lesen

Does CSR contribute to the development of rural young people in cultural tourism of sub-Saharan Africa? Evidence from the Niger Delta in Nigeria

Does CSR contribute to the development of rural young people in cultural tourism of sub-Saharan Africa? Evidence from the Niger Delta in Nigeria

Joseph I. Uduji, Elda N. Okolo-Obasi & Simplice A. Asongu January 2018 Abstract Handicrafts are key cultural products consumed in the Nigeria’s tourism industry. Owing to low entry barriers, as handicrafts require a low level of capital investment, there is potential to develop viable linkages between tourism and local handicrafts sectors that create economic opportunities for local artisans. Thus, we assess the impact of a new corporate social responsibility (CSR) model of multinational oil companies on the development of rural young people (RYP) in cultural tourism in the Niger Delta of Nigeria. Six hundred RYP were sampled across the rural Niger Delta region. Using the logit model, results indicate that RYP have remained widely excluded from the General Memorandum of Understandings (GMoUs) interventions in cultural tourism projects due to the traditional beliefs that cultural affairs are prerogatives of elders, a caveat to the youths. This implies that if the traditions of the communities continue to hinder direct participation of the RYP from the GMoUs cultural tourism project interventions, achieving equality and cultural change would be limited in the region. The findings suggest that since handicrafts are key cultural products consumed in the tourism industry, GMoUs can play a role in helping to create an appropriate intervention structure that will be targeted towards youth empowerment in the area of traditional handicraft. This can be achieved if the Cluster Development Boards (CDBs) would focus on integrating rural young artisans into local tourism value chains and ensuring that they benefit economically from the sector. The CDBs should aim at creating space for the views of rural young indigenous people’s handicrafts; emphasizing the value of indigenous knowledge, particularly on arts and crafts for tourists and expatriate in multinational corporations in Nigeria.
Mehr anzeigen

45 Mehr lesen

Causes and consequences of crude oil pipeline vandalism in the Niger delta region of Nigeria: A confirmatory factor analysis approach

Causes and consequences of crude oil pipeline vandalism in the Niger delta region of Nigeria: A confirmatory factor analysis approach

Over the years, crude oil spillage through pipeline vandalism is considered one of the major prob- lems of the region. Rising cases of pipeline vandalism by militant groups have significantly affected sources of revenues of government and oil companies operating in the region. The militants claimed to be fighting for the emancipation of the region from environmental neglect. Statistics have shown that Nigeria is losing well over 300,000 barrels per day (bpd) as a result of crude oil pipeline vandal- ism, which runs into billions of dollars in losses (James, 2014 ; NNPC, 2013 ). This has resulted in sig- nificant negative socioeconomic and environmental problems in the region with serious effects on human lives and farm lands. Although factors such as institutional weakness, lack of effective imple- mentation of environmental laws were hypothesized as the causes of vandalism in the region, they are considered neither exhaustive nor confirmed as no available empirical evidences can be found confirming the asserted causes of vandalism in the area. Against this background, this study em- ployed confirmatory factor analysis (CFA) on 12 latent variables in determining the real factors that cause and influence frequent pipeline vandalism in the Niger delta region, Nigeria.
Mehr anzeigen

16 Mehr lesen

Does corporate social responsibility (CSR) impact on development of women in small-scale fisheries of sub-Saharan Africa? Evidence from coastal communities of Niger Delta in Nigeria

Does corporate social responsibility (CSR) impact on development of women in small-scale fisheries of sub-Saharan Africa? Evidence from coastal communities of Niger Delta in Nigeria

23 Following the results of this analysis, it is therefore argued in this paper that embracing women’s participation in the GMoUs not only plays a significant role in fisheries development, but also enhances the relationship between the host communities in the Niger Delta and the MOCs. The gender insensitivity of MOCs in the exclusion of artisanal fisherwomen from the GMoUs intervention due to cultural norms of the people has created negative perception and doubt from feminine perspective (Table 9). Hence, any CSR initiative, no matter how laudable it is, does not always receive positive reaction from women in coastal communities of the Niger Delta (Figure 3). It is no surprise, therefore, that the coastal communities have remained a center of youth militants and incessant violent conflicts in the region (Uduji and Okolo-Obasi, 2018c). While Carroll (1991) is not consistent in his explanation of why CSR is depicted as a hierarchy, Visser (2005) explored the importance of cultural context in the determination of appropriate CSR priorities and programmes. This paper further traversed the need for flexibility in approaches to CSR policy and practice by multinational oil companies operating in the region of Niger Delta in Nigeria. Therefore, CSR in coastal communities should be focused towards the eccentricity of the socio- economic development challenges of the people’s traditional source of livelihood and basically informed by the socio-cultural influences in the region.
Mehr anzeigen

34 Mehr lesen

Corporate social responsibility and the role of rural women in sustainable agricultural development in sub-Saharan Africa: Evidence from the Niger Delta in Nigeria

Corporate social responsibility and the role of rural women in sustainable agricultural development in sub-Saharan Africa: Evidence from the Niger Delta in Nigeria

5 Fund estimates that the oil and gas sector in Nigeria accounts for over 95% of the foreign export earnings and about 65 percent of the Nigerian government revenue (IMF, 2018). The Niger Delta where multinational oil companies (MOCs) maintain a significant presence has become a theatre of incessant violent conflicts. The federal government of Nigeria (FGN) is in joint-venture agreements with the MOCs operating in the oil and gas sector of the country. The FGN owns and controls the land, including its natural resources in the subsoil. This is a major source of conflicts in the region (NDDC, 2001). Land can be acquired by the FGN for over- riding purposes by virtue of the country’s land use Act 1978. Notwithstanding, the negative impacts of the activities of the MOCs in the region include gas flaring, oil spills, environmental pollution, negative social impacts, conflict and violence among others (Eweje, 2006; Edoho, 2008; Akpan, 2006). Consequently, MOCs have been involved in a plethora of CSR activities in the Niger Delta and other parts of Nigeria. Each year, MOCs invest in social projects and programmes in the communities of the region. Their initial investments were primarily in agricultural development programmes and have gradually grown to include health care, roads and civil infrastructure, water projects, small businesses and education, which could benefit the local communities (Uduji and Okolo-Obasi, 2017). Over the years, MOCs have sought to improve on how they engage with these communities to deliver the projects (Ite, 2007). In 2006, they introduced a new way of working with communities called the Global Memorandum of Understanding (GMoU). The GMoUs represent an important shift in their CSR approach, placing emphasis on more transparent and accountable processes, regular communication with the grassroots, sustainability and conflict prevention (Alfred, 2013).
Mehr anzeigen

32 Mehr lesen

Environmental Conflict and Internal Migration in the Niger Delta Region of Nigeria

Environmental Conflict and Internal Migration in the Niger Delta Region of Nigeria

This bloody clash took place between ELF, a French – owned oil company and the seven- teen communities that make up the Egi clan in Bayelsa State, where oil was first discovered in Nigeria. Determined to seek redress for decades of neglect and degradation, the ag- grieved communities headed towards the flow station with “an assortment of sticks, tree branches, leaves, placards and banners” (Niboro, 1994). On the 1 st of February 1995, four months after the community reached an agreement with the company, about nine policemen reportedly under orders to recover a stolen computer from a member of the community came under attack from the local people, who killed one of the policemen involved in the recovery mission in the ensuing melee. On 19 February, the police embarked on a reprisal attack on the community with such devastating brutality that the number of dead remains unknown to this day. As the respected environmental journalist, Ima Niboro, reports, “... Obagi is a ghost town: a dead reminder of the perilous and eternal search for hydrocarbons. Its streets are bare as an empty hand. Fear, like a giant vacuum cleaner has sucked its inhabitant, man, and beast out of their ancestral homes... ” (1994: 14). Journalist Ima Niboro’s graphic de- scription of the Egi the incident was corroborated by a Niger Delta activist, Adaka Inemo, in an interview with him during my field study in Bayelsa State in 2005.
Mehr anzeigen

31 Mehr lesen

Palynology and stratigraphy of three deep wells in the Neogene Agbada Formation, Niger Delta, Nigeria. Implications for petroleum exploration and paleoecology

Palynology and stratigraphy of three deep wells in the Neogene Agbada Formation, Niger Delta, Nigeria. Implications for petroleum exploration and paleoecology

A great deal of palynological investigations has been conducted in the Niger Delta. Some of the pioneering palynological investigations in the Niger Delta include those of Van Hoeken-Klinkenberg (1966) on the Maastrichtian, Paleocene and Eocene pollen and spores from Nigeria and the systematic description of new sporomorphs from the Upper Tertiary of Nigeria (Clarke, 1966; Clarke and Frederiksen, 1968). The work of Germeraad et al. (1968) on the palynology of Tertiary sediments from tropical areas focused on the Niger Delta as one of the important basins on which the publication is based. Legoux (1978), Jan du Chêne et al. (1978) and Oloto (1992) have carried out palynological investigations including systematic description and age determination of the sedimentary sequences in the Niger Delta. The applied palynological studies in the basin include those of Morley and Richards (1993) who used Gramineae cuticle as a tool for climate change monitoring in the Late Cenozoic Niger Delta. The high resolution sequence stratigraphic work of Armentrout et al. (1999) from the Oso Field, Niger Delta emphasised the importance of palynology in detailed sequence stratigraphic resolution. Also van der Zwan and Brugman (1999), indicated the importance of palynology as one of a number of biosignals in the EA Field, Niger Delta. A recently published paper by Ige (2009) is based on the pollen and spore record from the Niger Delta and their palaeo-vegetational implications. Oboh et al. (1992) and Oboh (1995) are other important palynological contributions in the Niger Delta Basin.
Mehr anzeigen

190 Mehr lesen

The impact of CSR interventions on female education development in the rural Niger Delta region of Nigeria

The impact of CSR interventions on female education development in the rural Niger Delta region of Nigeria

19 this 62%, 31% desire a visa to travel overseas, 19% would prefer to be employed even as a cleaner in the MOCs; whereas only 12% want to start their own business. Uduji and Okolo- Obasi (2018b) have the same view that most of the young girls in the region who are forced into marriage by their parents are completely banned by their parents from going to school. Also Uduji et al (2019b) concede that some of the girls excelled in studies, so it is safe to say that in the Niger Delta, bright rural young girls, who could potentially help develop their local communities, are shut off, and their potentials to shine extinguished. This calls for the need for policy dialogue and advocacy activities by MOCs, working with governments and addressing educational and economic opportunity policies and support for increased levels of government aid for female education in the region; as the obstacles to female access to education in the region are significant barriers to social and economic progress in the Niger Delta. In other words, this finding prompts the consideration that lack of proper education is another reason why rural people in the Niger Delta get their children married at a young age; when their culture does not consider the post-marriage life the girls will have to face and child birth complications. Moreover, due to the lack of education, rural people in the region tend to hold onto many unhealthy traditional beliefs and norms. Pérouse de Montclos (2014) agrees that female education in Nigeria is not just a matter of improving earnings potential in the long term, but its power extends to matters of life and death. Oniye (2008) confirm that the gains associated with female education do not only manifest in the long term, but also can pay off more acutely, especially in the areas of health, labour force participation and human security. Smith-Greenaway (2013) concurs that better educated women become healthier mothers that would take care of their children properly. Unterhalter et al (2013) added that female education directly impacts productivity levels and participation rates in the labour force.
Mehr anzeigen

33 Mehr lesen

Youth empowerment in non-timber forest products (NTFPs) of sub-Saharan Africa: The role of corporate social responsibility in Niger Delta, Nigeria

Youth empowerment in non-timber forest products (NTFPs) of sub-Saharan Africa: The role of corporate social responsibility in Niger Delta, Nigeria

Theoretical perspective Carroll’s (1991) CSR Pyramid is probably the most well-known model of CSR, with its four levels indicating the relative importance of economic, legal, ethical and philanthropic responsibilities respectively. However, the exploration of CSR in Africa by Visser (2006) was used to challenge the accuracy and relevance of Carroll’s CSR Pyramid in an African context. Thus in developing countries, the absence of government action in providing amenities for its citizens accentuates the role of multinationals in CSR and philanthropy is not regarded as CSR in Western countries (Frynas, 2005). Muthuri (2012), relying on the extent literature on CSR in Africa, posited that the CSR issues prevalent in Africa include poverty reduction, community development, education and training, economic and enterprise development, health and HIV/AIDS, environment, sports, human rights, corruption and governance and accountability. According to Uduji and Okolo-Obasi (2017), philanthropic initiatives as CSR by companies are prevalent in Nigeria. Amaeshi et al.(2006) have argued that the Nigeria conception of CSR is remarkably different from the Western version. It is also proposed by Uduji and Okolo- Obasi (2018c) that Carroll’s CSR Pyramid may not be the best model for understanding CSR in rural Africa. The above theoretical underpinnings and the contextualization of CSR from an African perspective could theoretically elucidate the probably connection between economic empowerment of rural young people in non-timber forest products and their potential benefit in sustainable livelihood from GMoUs of oil companies. This study adopts quantitative methodology, but views the outcome from Visser’s Africa’s perspective.
Mehr anzeigen

35 Mehr lesen

OPUS 4 | Sustainable environmental management in the Niger Delta Region of Nigeria: effects of hydrocarbon pollution on local economy

OPUS 4 | Sustainable environmental management in the Niger Delta Region of Nigeria: effects of hydrocarbon pollution on local economy

Poverty is linked to the environment in complex ways, particularly in African economies, which are based on natural resources (World Bank, 1990b). Degradation of these resources reduces the productivity of the poor – who most rely on them – and makes the poor even more susceptible to extreme events (meteorological, economic, and civil unrest as we have in the Niger Delta region). Poverty makes recovery from such events even more difficult, and contributes to lowering social and ecological resistance. Poverty is also a factor in accelerating environmental degradation as seen in the Niger Delta region, since the poor, with shorter time horizons and usually less secure access to natural resources, are unable and often unwilling to invest in natural resource management (for example, soil conservation and fertilizers). In addition, poor people are often the most exposed to environmental damage, because they cannot afford, for example, to purchase safe water or to live in a neighborhood that is less polluted (World Bank 1990b). Reducing poverty will often lead to improved environmental quality and vice versa (Mink 1993; World Bank 1992a).
Mehr anzeigen

231 Mehr lesen

Citizenship and resource control in Nigeria: the case of minority communities in the Niger Delta

Citizenship and resource control in Nigeria: the case of minority communities in the Niger Delta

Au Nigéria, les affrontements au sein de la population pour le contrôle des res- sources naturelles dans les régions du delta du Niger, zones d’extraction du pé- trole, tiennent depuis le début des années 1990 un rôle central dans les débats sur la question nationale et la politique envers les minorités ethniques ainsi que sur le thème de la dégradation de l’environnement. Ceci peut être largement rapporté aux activités de Ken Saro-Wiwas et de son mouvement pour la survie du peuple Ogoni (MOSOP), qui contribua fortement à populariser au niveau international ces questions. Les études scientifiques existantes se sont concentrées sur la politi- que des minorités, la restructuration du fédéralisme nigérian et la dégradation de l’environnement. En revanche, très peu de recherches ont été menées sur l’importance et les implications de la question du contrôle des ressources naturel- les pour les droits civiques de la population nigériane et en particulier pour ceux des habitants des régions d’extraction du pétrole. La marginalisation des droits civiques des minorités des régions pétrolières a nourri les revendications d’un mouvement en faveur de droits civiques ethniques comme fondement pour le contrôle des ressources naturelles. Cette contribution démontre que la pratique d’un réel fédéralisme au Nigéria doit être accompagnée d’une décentralisation pertinente du pouvoir au niveau local afin que la population locale puisse mieux contrôler la richesse de ses ressources minérales.
Mehr anzeigen

25 Mehr lesen

Modeling Environmental and Social Impacts of Bioenergy from Oil Palm Cultivation in Nigerian Niger Delta

Modeling Environmental and Social Impacts of Bioenergy from Oil Palm Cultivation in Nigerian Niger Delta

Public support for bioenergy deployment is widely debated, and it is agreed that the substitution of traditional fossil-fuel energy sources by bioenergy can provide benefits for energy security and potential for GHG mitigation. However, the rapid expansion of biofuels production from some feedstocks (e.g., oil palm) has raised concerns regarding land use and the implications of cropland expansion for net GHG emissions. Thus, the focus for future bioenergy use has shifted toward second-generation feedstocks that may alleviate these issues of converting forest land to cropland. However, there are some technological and logistical hurdles to overcome before second-generation feedstocks can be used to generate large quantities of bioenergy at competitive costs [48]. Conclusions from this study are that market-based instruments such as a carbon tax alone are not sufficient for preserving the remaining forest area in Nigeria. Therefore, political willingness to support an infant industry such as the bioenergy industry have to couple a carbon tax with conservation instruments such as Payment for Ecosystem Services (PES). NGA–FASOM showed that, to achieve a negative GHG reduction in the forest and agricultural sector in Nigeria, a carbon tax above $80/ton is required. In Nigeria, a subsidy on bioenergy products does not have any significant effect on total social welfare. Another general conclusion that emerges from this study is that a subsidy on the bioenergy industry in Nigeria does not translate into any substantial comparative advantage on bioenergy feedstocks. Furthermore, bioenergy consumption will not be significantly affected by a subsidy. In addition, we conclude that following the stipulated bioenergy mandates will cause a substantial hike in food prices in Nigeria. We recommend further studies to look at the potential and realization of the bioenergy targets as stipulated above using second-generation feedstocks and placing a physical restriction on land-use change.
Mehr anzeigen

99 Mehr lesen

The Niger delta: aspects of human health risk associated with the petroleum industry

The Niger delta: aspects of human health risk associated with the petroleum industry

from the geopolitical and socio-cultural structure of Nigeria, to practices that appear to be specific to the oil and gas industry. The oil and gas industry has always had strong lobbies and influence government policy and laws globally. Operation in the upstream petroleum sector is costly and capital intensive, and most of the companies involved have deep enough pockets to influence policies, laws and regulations through powerful lobbyist in the countries where they operate. Regularly, the oil and gas industries have been reported to fund political campaigns and bankroll politicians. It is instructive that in the United States of America, most wastes derived from the upstream oil and gas industry are exempt from USEPA regulation for hazardous wastes (U.S. EPA., 2002). In 1980, the US Congress gave a conditional exemption for exploratory and production wastes from the oil and gas industry from hazardous management under the Resource Control and Conservation Act (RCRA), The Clean Water Act (CWA), and the Safe Drinking Water Act (SDWA). The wastes exempted include produced water, produced sand, drilling fluids and muds, tank bottoms, among several others (Puder and Veil, 2006). Nigeria was without any formal dedicated environmental regulations before 1988, when in a knee-jerk reflex to a toxic waste dump in some parts of the Niger Delta, the Federal Environmental Protection Agency (FEPA) was created by the erstwhile military administration in the country, to enforce the Harmful and Toxic Waste Decree of the same year (Echefu and Akpofure, 2002). Prior to the formation of FEPA, the principal regulatory tool in the petroleum industry in Nigeria was the Petroleum Act of 1969, whose enforcement fell under the Department of Petroleum Resources of the Ministry of Petroleum Resources. Apparently, the major environmental policy thrust of the Petroleum Act 1969 was pollution abatement (Orubu et al., 2004).
Mehr anzeigen

199 Mehr lesen

Armed rebellion and the future of self-determination in the Niger Delta

Armed rebellion and the future of self-determination in the Niger Delta

The Niger Delta region of Nigeria has been attracting both local and international attention because of the character and dimensions of violent rebellion and the struggle for self-emancipation in the area. The agitation predates Nigeria’s Independence and the area has witnessed different Nationalist characters. The bases of the agitation remain largely the same from the different epochs but the responses of the Nigerian state has not been different completely from that of the Colonial Nigerian government until Yar’dua amnesty deal. The deal may at the end be another cosmetic attempt at reducing tensions in the area or at best, a policy seeking a limited peace but not a lasting solution to rebellion and struggle for self emancipation. The amnesty deal could, in a limited time, just set the basis for the transformation of the struggle for self emancipation in the Niger Delta.
Mehr anzeigen

10 Mehr lesen

An advanced three-dimensional simulation system for safety analysis of gas cooled reactors

An advanced three-dimensional simulation system for safety analysis of gas cooled reactors

As three-dimensional time-depending modelling becomes more and more a standard in reactor analysis, it is to become state of the art for HTRs as well. This work addresses these needs by coupling a three dimensional time-dependent neutron transport code TORT-TD to a 3-dimensional time dependent thermal fluid dynamic code ATTICA 3D by means of a common interface exchanging power distributions and fuel and moderator temperatures, respectively. Along with the coupling, the single components are intro- duced. The major ideas in TORT-TD that solves the time-dependent neutron transport equations by transforming the set of equations into a source driven problem with the introduction of a time-dependent external neutron source were briefly explained. Also, an additional parameter, the hydrogen density, to vary the macroscopic cross sections as consequence of water ingress was introduced. For the thermal fluid dynamic com- ponent ATTICA 3D the principle transport equations for the porous medium approach were explained. These transport equations together with a set of constitutive equations, e.g. equations of state for the gas and gas mixtures, heat transfer coefficient, radiative heat transfer, effective heat conductivity of the pebble bed were presented. Interested readers may find the numerical solution of the equation system to be solved on a spa- tial grid applying the finite volume method, and a method of time integration with the help of the backward differentiation formulae in the appendix.
Mehr anzeigen

183 Mehr lesen

Design, Fabrication, and Characterisation of Three-Dimensional Photonic Quasicrystals

Design, Fabrication, and Characterisation of Three-Dimensional Photonic Quasicrystals

In Fig. 4.4, the setup is schematically sketched. A 100 W power tungsten halogen lamp, yielding black-body emission with a surface temperature of around 3000 K, serves as light source. The light is coupled into an IR/VIS optical fibre with a 200 µm core by the lens L1 to be transmitted to the actual transmittance setup. Lens L2 collimates the light emerging from the fibre. Using polariser P1, the linear polarisation of the light is controlled which is finally focused onto the sample by the microscope objective MO1 (Zeiss Achroplan LD 20x KO, NA=0.4). The sample itself is mounted onto a goniometer placed on a rotation stage such that the sample can be aligned strictly perpendicular to the optical axis. Furthermore, it is possible to rotate the sample by defined angles with respect to the normal incidence case to allow for angle-resolved transmittance measurements. By closing the circular aperture CA1 placed directly in front of the microscope objective MO1, the half-opening angle of the light focused onto the sample can be reduced to 5°. By inserting a 200 µm pinhole 7 right in front of the microscope objective MO1, it is even possible to actually nearly accomplish the ideal of an incident plane wave, reducing the full-opening angle down to even 1.5°. The combination of the microscope objective MO2 and the circular aperture CA2 behind the sample allows for collecting the transmitted light within a specific half-opening angle reaching from 24° (open circular aperture) down to 5° (closed circular aperture). A second polariser (P2) can be inserted into the setup to analyse the polarisation state of the transmitted light. Lens L3 in combination with the objective MO2 is used to image the sample to an intermediate image plane in which knife-edges (KE) are placed to spatially select the sample area which is to be studied. This selected area is finally imaged onto an IR/VIS optical fibre with a 200 µm core using lens L4 and microscope objective MO3 (Newport M-10x, NA=0.25). The fibre is then connected to the detecting system, which is typically an optical spectrum analyser (OSA, Ando AQ 6315 B) with a fairly large spectral range from 500 nm to 1750 nm. For some delicate measurements required in the course of this thesis (see section 5.3.3), however, the output of the optical fibre is coupled via lenses L6 and L7 to a grating spectrometer (SPM, Acton SP 2150i, focal length f=150 mm, entrance slit set to 30 µm) connected to a sensitive liquid-nitrogen cooled back-illuminated silicon CCD camera (CCD (Si), Roper Scientific, LN/CCD-1340/100-EB), which gives the opportunity to detect transmitted light of even quite low light levels with high resolution (of ≈ 1 nm) [91]. Yet, this detecting system has the drawback of a limited spectral range – from 700 nm to 840 nm wavelength for the applied grating (300 per cm, blazed at 1.0 µm, central wavelength set to 800 nm).
Mehr anzeigen

142 Mehr lesen

Three Dimensional Numerical Modeling of Pier Scour

Three Dimensional Numerical Modeling of Pier Scour

For the investigations in this paper a numerical model is used (Olsen, 2007). The Reynolds-Averaged Navier-Stokes (RANS) equations are solved in all three dimensions, making it fully three-dimensional. The standard k- ε model (Rodi, 1980) was used to compute turbulence. Using the finite-volume approach on a structured non-staggered grid, the RANS-equations and the equations of the turbulence model are numerically discretized with the first order upwind differencing scheme and the second order upwind differencing scheme. The non-hydrostatic pressure is computed with the SIMPLE method (Patankar, Spalding, 1972). The free surface elevation is determined with the help of the pressure field, using the Bernoulli equation.
Mehr anzeigen

6 Mehr lesen

Three-Dimensional Penrose Tilings and Self-Similarity

Three-Dimensional Penrose Tilings and Self-Similarity

Abstract. We investigate a 3-dimensional analogue of the Penrose tiling, a class of 3-dimensional aperiodic tilings whose edge vectors are the vertex vec- tors of a regular icosahedron. It arises by an equivariant projection of the unit lattice in euclidean 6-space with its natural representation of the icosahedral group, given by its action on the 6 icosahedral diagonals (with orientation). The tiling has a canonical subdivision by a similar tiling (“deflation”). We give an essentially local construction of the subdivision, independent of the actual place inside the tiling. In particular we show that the subdivision of the edges, faces and tiles (with some restriction) is unique.
Mehr anzeigen

40 Mehr lesen

Show all 10000 documents...

Verwandte Themen