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Cameroon has vast renewable energy resource potentials, with a hydropower potential of about 55,200MW, second only to the Democratic Republic of Congo in Africa. So far, its energy needs are met by 4.8% hydropower (which accounts for less than 5% of its total hydropower potential), 0% wind and 0% solar. Cameroons’ energy sector still goes through insufficient electrical energy production, especially during the heart of the dry season, which runs from December through March. Coincidentally, the wind and solar power potentials for Cameroon are at their peak during these months and could conveniently supplement for the shortfalls in generation during these periods. In this research, technical analysis were carried out to determine the wind and solar energy resource potentials for Cameroon using the RETScreen software tool provided by CANMET Canada. These analysis revealed that the northern regions of Cameroon had higher wind and solar resource potentials than any other location in Cameroon. A 2MW installed wind energy capacity would be capable of generating well over 1.5GWh electrical energy per year, while a 2KW installed solar energy capacity will be capable of generating well over 3MWh electrical energy per year. In the final sections, financial analysis were carried out to determine the economic viability of such projects and the possibility for self-financing. Emission analyses were also done based on the ability for such projects to offset greenhouse gas emissions and ensure sustainability in the energy sector. The analysis for Maroua revealed that 78.6tCO2/yr for wind and 0.1tCO2/yr for solar could be reduced by those installations. Finally, the legislations and legal frameworks governing the energy sector in Cameroon were dissected to determine possible weaknesses and constraints limiting the use, promotion and development of the full potential of Cameroon’s renewable energy resources.
This study explores the interplay between the UNESCO status and climate governance in World Heritage cities. With climate change posing significant threats to living urban landscapes, local governments and public actors strive to implement sustainable and resilient strategies. However, complications arise when cities attain the World Heritage status, complicating climate governance practices. Qualitative research, involving interviews with key stakeholders from the Climate and Monument Protection Departments in Lübeck, Regensburg, and Bamberg, reveals a negative impact of cultural heritage on climate governance. The study contends that, when harnessed effectively, cultural heritage can contribute to the sustainability and resilience of cities in addressing climate change. It emphasises the necessity for flexibility, collaboration, and a human-centric approach, advocating for a common understanding and prioritisation of human life within climate governance. In conclusion, this research underscores the importance of viewing heritage as a dynamic component integrated into cities' climate governance strategies.
Conservation of heritage sites is an integral part of history and culture through which new generations can learn about their forefathers education, professionalism, cultural characteristics as well as their civilization. Almost all countries of the world tend to conserve their historical sites for their own generations and travellers from abroad. Despite Bangladeshs economy is becoming stronger, it is not paying enough attention to the development of archaeology to conserve its heritage sites. Unlike many other developing countries, Bangladesh tends to considers it a luxury to preserve it’s heritage sites. It is mainly because of the scarcity of land. The tiny country has a huge population (about 180 million), the density of which is perhaps the highest in the world.
Apart from some very significant heritage sites, most others are awfully neglected. Lack of education and awareness among the respective local people and other stakeholders are also responsible for most of the heritage sites facing threats of demolition, vandalism, losing authenticity and integrity.
Panamnagar, the case study for this thesis paper, is not apart from the above scenario. It is the last surviving intake city of lost Bengal. The place witnessed Mughal emperor, British rule, the partition of Bengal, Liberation war of Bangladesh, Hindu-Muslim riot, illegal habitation of people, forced eviction and abundance. The historic city went through lots of historical events and is still standing as a testimony to the golden era of Bengal. Currently, this heritage site is facing multiple threats to its existence and authenticity. The city is vacated by the authority - the Department of Archaeology. But as the local people are not aware of the historic value of the site, they are not at all cooperating with the authority. Meanwhile, the authority is trying to incorporate adaptive reuse of the site to give life to it again and collect revenue for the maintenance. But they are doing it without assessing the cultural significance of the site properly, which could be a potential threat for the authenticity of the heritage site. Thus, this paper has focused on assessing the cultural significance of the heritage site, with a hope that it will help the authority to make policy decisions for the conservation of the site more cautiously. To assess the cultural significance properly, history and architectural significance are described briefly. A site analysis has been conducted to understand the current site condition properly. The paper concludes with statements in support of the cultural significance of Panamnagar site and recommends appropriate conservation tools to sustain its significance.
Rural electrification has been one of the challenges faced by the government of Ghana due to extremely high cost of electricity extension to the rural areas. In order to meet up this challenge, the government of Ghana has been keen with the introduction of renewable energy programs as a solution for rural electrification. However, most of programs are also faced with the problem of being sustainable. After government and sponsors hand-over completed project to local users, they usually last only few years of their life span and are abandoned. This challenge has inspired this study to identify the potential barriers to the sustainability of rural electrification programs through technical and socio-economic evaluation of a solar PV rural electrification project in Ghana.
The approach of this study selected an on-going solar PV project (community solar system-CSS), that has been introduced on a pilot base across the whole of Ghana, which is to be adopted as a standard system for electrification solutions in rural areas in Ghana. This project was subjected to both technical and socio-economic evaluations covering 13 rural communities across the southern part of the country. Stakeholder interviews and review of literature were additional methodologies employed to gather information pertinent to the theme of the study.
The results of the study show that technically, the CSS project has simple design and operational technologies, which gives it high integration potential. However, the project faces the problem of technology misuse by the rural users and frequent failure of its components. The socio-economic barriers identified are: (1) ineffective management of the project due to a long chain of bureaucratic administrative management system, inadequate monitoring and supervision, and inconsistency in standardizing the cash flow of the project, and (2) low electricity capacity of the CSS project and other similar small scale renewable projects to meet the electricity requirements of the rural populates. These problems lead to gradual decline of users’ interest for such small scale renewable energy projects and subsequently result in project abandonment. It was concluded that small scale renewable energy programs lack the capacity to fully meet the energy requirement of rural populates; however, they are crucial as intervening solutions and play key role in rural development.
The Electric power crisis is one of the major problems in Bangladesh, the gap between demand and generation is increasing day by day. Moreover, most of the power plants are gas based which will be phased out in future. An alternate electric supply is an essential part for electrifying the developing countries, in this context an innovative approach of rural electrification including DC microgrid, mini-grid and nanogrid would be technically and economically feasible. The thesis draws also attention on the development of technology which enables community owned power system to emerge in the rural areas based on distributed SHS and demand of that community.
Firstly, the electric status and renewable potential in Bangladesh are studied and considered those data into the software based simulation to analysis the technical feasibility to implement DC microgrid by Homer pro tools. The distributed RES (Renewable Energy sources) considered solar PV and biomass. The booming of a large number of individual SHS (Solar Home System) in Bangladesh, bottom-up energy sharing concept would have studied to configure the optimal design of microgrid system and different configuration including grid connected and DC and AC system studied.
Secondly, The PV module is highly dependent on cell temperature and solar irradiance, the ambient temperature, and solar irradiance mathematical equation have been considered to model and simulate in MATLAB/SIMULINK based environment. Similarly charge controller, battery operation, and performance analysis with respect to the PV model. In the distributed energy sources are mainly SHS including large size and regular also model and simulate in MATLAB/SIMULINK software. For instance, the thesis mainly focuses on an optimal design, planning, sizing of DC hybrid microgrid, the SHS, and biomass-based power system with the goal of maximizing the efficiency and reliability. Homer Pro tool used in the work for design an optimal configuration and sizing for technical feasibility.
Finally, a model of DC microgrid compresses with micro sources like SHS systems, µ-CHP, the household loads model in MATLAB/SIMULINK. Decentralized SHS control strategies (droop control) and operation also design and model in MATLAB/SIMULINK environment, where DC – DC converter needs to couple SHS and DC microgrid.
Determination of specific metabolic activities of anammox bacteria and their sensitivity to oxygen
(2013)
The discovery of Anammox bacteria has bridged our knowledge gap in the nitrogen cycle. This is because it explained the direct conversion of nitrite and ammonium to nitrogen gas in many reducing natural environments. However, it has been found that the presence of oxygen is an important determinat factor for certain biochemical processes and distribution of organisms in the environment. In this work, two methodological approaches were used to investigate the specific metabolic activities of Anammox bacteria and their sensitivity to oxygen using a mixed biomass culture. Two laboratory-scale bioreactors were maintained and the biomass in the reactors served as the inoculum for the investigations. The molecular characterization of the biomass was done using the Fluorescence in situ hybridization (FISH) technique. The specific Anammox activity (SAA) and important inhibition kinetic parameter characterization were estimated while monitoring activities of the biomass using several batch experiments.
The results of the biochemical characterization revealed that several microbial activities such as denitrification, nitrification, dissimilatory nitrate reduction to ammonium and Anammox processes were competing in the bioreactors. These were observed in the analysis of effluent recirculation of the feed solutions in the bioreactors, however, the Anammox process was predominant. An optimum sonication time top of eight minutes was established used to determine the average optical density to dry mass (OD: DM) ratio of 0.87 in the biomass. The FISH characterization estimated 60.4 % ± 14.6% (mean ± standard deviation) Anammox bacteria concentration in the biomass of Bioreactor 1. The Anammox bacteria were made up C. Kuenenia Stuttgartiensis (̴ 78%) and the remaining C. Brocadia Fulgida.
The maximum SAA of 0.025 mgNH4-N (TSSAnammox-1. d-1) and 5.4 mgNH4–N (1011 CellAnammox-1. d-1) for ammonium, and 0.04 mg N2-N (TSSAnammox-1. d-1) and 9.4 mgN2–N (1011 CellAnammox-1. d-1) for nitrogen gas were found in the biomass. While a binding affinity constant Ki = 0.07 mgO2 /l, maximum half inhibition concentration IC50 ̴ 0.2 mg O2 /l and KM = 50 mg/l were estimated for the inhibition kinetics of oxygen in the biomass. The low Ki value found in this study indicates that oxygen is an efficient inhibitor for Anammox activities and concentrations between 0.4 - 0.64 mg O2 /l can lead to complete inhibition of Anammox activity. However, this process is reversible. Finally, the implication of this inhibition kinetic results might be important in tracing the distribution of Anammox processes in natural environments where fixed nitrogen is present.
The master thesis at hand examines the potential of district heating in Lusatia. The thesis follows the approach of first identifying technical and economic potentials in general and then transferring them to the study region. For the quantitative determination of district heating potential in Lusatia, the status quo is determined and a GIS-based analysis is carried out with regard to minimum heat demand densities. The extent to which district heating is suitable for climate-neutral heat supply will be investigated using the potential of renewable and waste heat energy sources. Furthermore, the regional economic effects of developing these potentials are examined. The results show that despite an overall decline in heat demand, there is potential to increase the relative share of district heating in Lusatia. In terms of climate neutrality, district heating in Lusatia offers special opportunities. Solar thermal energy and Power-to-Heat are of particular importance due to the rural character of Lusatia and its status as an energy region. From a regional economic perspective, climate-neutral district heating has a positive effect on value added and employment.
Soils deposited can undergo a sudden change in the structure when they are inundated with water resulting decrease in the volume. This process is known as water induced compaction. The decrease in volume occurs without any change in external loads and is only caused by the water, which results in the settlement of soil surface having a resultant potential to damage the structures. The water induced compaction process is characterized by sudden change in the voids or pores of the soil that are loaded at their natural water content and flooded. The objective of this thesis work was to understand the water induced consolidation process at agriculturally used reclaimed soils. The approach was to reproduce the situation occurring when the soil was subjected to water induced compaction at defined loads typical in the top soil (0 kPa to 20 kPa). The glacial till used for the experiments was sampled in the Lusatian lignite-mining district located about 100 km southeast of Berlin, Germany. Sediment samples for different investigations were taken from the pre-cut section at 1500 m west of the eastern end from 3 m depth till 10 m depth. The glacial till used for the experiments derived from the sediment layer of Warthe sub-stage of the saalian glaciation. To characterize the soil properties at the pre-cut section, parameters like grain size distribution, soil bulk density, calcium carbonate content (CaCo3) and water retention characteristics were measured. The stability of the glacial till was evaluated using parameter pre-consolidation load. This was done in three sub-steps. The first step was determination of the stress-strain behaviour under natural conditions. In the second step the stress-strain behaviour of disturbed dry samples was simulated, which would be the situation in summer when the glacial till dries during transport. In the third step we saturated the disturbed dry samples which were subjected to different preloads to simulate the effect of saturation and re-compaction by precipitation. This work was exemplarily done for undisturbed samples and also for disturbed dry samples from 4 depths (4 m, 6 m, 8 m, and 10 m). Disturbed dry and saturated conditions were tested for samples from depths 4 m and 8 m. i) It was found from the grain size distribution that the soil profile is uniformly distributed with different particle sizes. High soil bulk density was recorded, which were in the range of 1.9 g cm-3 to 2.0 g cm-3. We observed that the carbonate content increased with the depths, in our observation it increased up to 5.4 %. From the water retention characteristics we observe that the samples from 4 m and 10 m depth do not have coarse pores where as 6 m and 8 m depth samples have coarse pores. ii) We observed that the undisturbed samples showed a flat curve having the initial void ratio and final void ratio values within a small range (between 0.2 and 0.4), where as the disturbed dry and the disturbed saturated curves showed a huge difference in the initial and final void ratio values. The difference was decreasing with the increase in pre-loads. We found that pre-consolidation stress values obtained were not increasing with the increase in depth. The disturbed saturated samples from the 4 m depth showed over-estimation of the results, where as the disturbed saturated samples from 8 m appeared to be realistic. We found that the magnitude of water induced compaction increased with the increase in preloads and a decrease with respect to the depths
Lens epithelium derived growth factor (LEDGF), is known to be overexpressed in different solid cancers and cancer cell lines but is also involved in acquired immunodeficiency syndrome (AIDS) and diverse inflammatory diseases. Due to its chromatin-binding ability, it acts as a transcriptional coactivator, promoting anti-apoptotic pathways leading to increased tumor aggressiveness and chemotherapy resistance. In this thesis, the role of LEDGF in laryngeal cancer cells was investigated. Thus, a knock-out of LEDGF in HEp-2 cells was successfully generated by CRISPR/Cas9 technology. Moreover, LEDGF-deficient HEp-2 cells exhibited a decreased proliferation and migration, as well as an increased chemotherapy sensitivity towards topoisomerase II inhibitor etoposide. The DNA damage response was in more detail investigated, where LEDGF depleted cells showed a drastic reduction in the recruitment of downstream damage-response related proteins, more precisely replication protein A subunit of 32kDa (RPA32), and an increased amount of DNA fragmentation, highlighting the role of LEDGF in homology-directed DNA repair.
In addition, a efficient method was established to allow genomic tagging of LEDGF at its C-terminus with EGFP which enables the monitoring of LEDGF in living cells. Therefore, an efficient Cas9-mediated DNA DSB induction was supplemented with a DNA template containing homology arms to the C-terminus as well as the EGFP sequence to allow homology-directed repair. Subsequently, EGFP-expressing cells were FACS sorted and single cells expanded. Almost all test clones showed a homozygous genotype for LEDGF-EGFP fusion which exhibited the typical nuclear pattern of LEDGF.
Wind energy is a growing concern over the present awareness of lethal impact of green house gas emission. This energy source has been proven a promising alternative to fossil fuel based energy. Increased onshore wind capacity and decreased amount of low roughness wind sites has inspired the wind energy researchers to explore the possibilities of wind energy from high roughness sites such as urban area. Moreover, exhausted grid capacity between the wind energy producer from remote area and the consumer at city is also a major constrain for wind energy expansion. Driven by such motivation, this thesis has explored possibilities of wind energy conversion from buildings where energy is needed the most. Urban topography is known to be highly turbulent region considering its roughness characteristics.
Wind energy yield from urban aerodynamics is a vast arena of experimental research. Within the time frame of the thesis period and available opportunities, a brief description about the wind energy assessment modelling approach from urban flow was outlined. There are several possibilities of wind energy yield from the built structure, but only building integrated duct was focused in this thesis.
Time-averaged and global wind speed on the building integrated ducts, flow around the buildings was measured from wind tunnel and numerical analysis. Available wind energy yield and turbulence present in the locations measured from the flow was calculated based on the wind tunnel data and summarized with the pros and cons of the particular geometry. Elliptical duct configuration was found to achieve maximum energy yield from the omnidirectional free stream flow. However, simple rectangular duct configuration was determined as most efficient and optimized considering its simplicity, financial feasibility and relative energy yield with other duct configuration. The thesis also showed that on roof configuration is also very promising for wind energy exploration from the omnidirectional free stream flow.
Necessary recommendations were made based on available result for future development of the research approach. Scope and opportunities was mentioned. This investigation has proved that it is possible to extract limited amount of wind energy from building augmented ducts using concentrator effect of the building exterior. Thus, the thesis concluded that the wind energy yield from building augmented ducts using the concentrator effect of the building exterior is a promising renewable energy source.