@phdthesis{Forbid2012, author = {Forbid, George Teke}, title = {Thermal recycling of plastic waste using pyrolysis-gasification process for energy production}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-25269}, school = {BTU Cottbus - Senftenberg}, year = {2012}, abstract = {The disposal of mixed waste in landfills, dump sites and open burning without material and energy recovery leads to resource loss, causes health problems, pollution and littering. Increasing energy demand for industrial and domestic application with rising costs due to scarcity motivates a constant search for alternative clean energy sources. Recovering energy from waste presents various incentives e.g. creating jobs, alleviating poverty, combating and mitigating climate change, protecting the environment and reducing dependence on traditional fuels sources. Hence, plastics end up in landfills, surface waters and ocean bed with serious negative impact on terrestrial and aquatic biodiversity. Plastic waste with high calorific value (36-46MJ/kg) occupies the greatest portion of landfill space. Hence, using an appropriate technology to transform waste plastic to a hot gaseous mixture which is burned in-situ produces enormous amount of energy without pollution. Based on this hypothesis, the study objectives accomplished were to: 1.Characterise, quantify and classify waste fractions and plastic components common in MSW by manual sorting 2.Evaluate options for sustainable plastic waste management especially for developing countries 3.Design, construct, test and optimize an appropriate technology that applies pyrolysis and gasification processes to convert non-PVC plastic waste to energy 4.Assess the efficiency of the technology based on the functioning, the engineering, mass and energy analysis including socioeconomic and environmental impacts An integrated methodology involving review of current literature, field and laboratory experiments on mixed waste and plastic waste analysis was used. In addition, the pyrolysis-gasification technology (PGT) was conceptualised, designed, constructed, tested and optimised at BTU Cottbus, Germany; Lagos, Nigeria and Dschang, Cameroon. Field studies involving natural observation, interviews, personal discussions and visits to waste management organisations and disposal sites were conducted in various cities in the three case study countries. A resource-oriented manual sorting using the resource-recovery scavenging approach (RESA) simulating integration of scavenger's activities in waste sorting was conducted at BTU and Lagos. Major results obtained include: •Characterization, quantification and classification of a dry sample of commingled MSW at Cottbus gave major waste fractions in order of decreasing abundance as 23.15\% of residue waste, 19.75\% of paper and cardboards, 17.80\% of plastics, 14.63\% of textiles and diapers, 10.06\% of food waste and 9.55\% of glass. An overall 33.21\% of waste sample is compostable for manure, 52.2\% usable as feedstock in the PG technology and 99.81\% of total sample having a material or energy recovery potential. In Lagos, Nigeria main fractions were 29\% of plastics, 36\% of residue waste, 17\% of soil/sand, 7\% of paper with overall 41\% usable as feedstock in PG technology, 39\% compostable, 3\% of recyclable (metal and glass). Sand can be recovered from the soil/sand fraction for construction. Excluding the sand/soil mixture, 83\% of the total waste sample has potential for material and energy value. •An appropriate technology that applies principles of pyrolysis and gasification to convert non-PVC plastic waste to energy was designed, constructed, tested and optimized with respect to: (i) Successful functioning with conversion of averagely 98.51\% of input constituting of 82.78-98.21\% of charcoal and 96.72-99.27\% of plastic to heat energy (ii) Evaluation of socioeconomic and environmental impacts based on pyrolysis and exhaust gas and ash residue analysis showed absence of VOCs, heavy metals and pollutant organic and inorganic compounds; (iii) Safety and risk assessment to indoor pollution is very low; (iv) Assessment of the WTA and WTP indicated that 94\% of respondents in Lagos, Nigeria and Porto Novo, Benin were willing to accept and pay for this technology. Using the PG technology improves local communities' ability to achieve clean, efficient and safe cooking and heating energy with potential for combine heat power generation.}, subject = {Kunststoffabfall; Vergasung; Pyrolyse; Forstschutz; Energier{\"u}ckgewinnung; Pyrolyse-Vergasung Technologie; Kunststoffabfall; Eind{\"a}mmung des Klimawandels; Ressource-Recovery-Scavenging-Ansatz; Waldschutz; Pyrolysis-gasification technology; Waste plastics and biomass; Climate change mitigation; Resource recovery scavenging approach; Forest protection}, language = {en} } @phdthesis{Fotang2023, author = {Fotang, Chefor}, title = {Conservation status and ecology of the Nigeria-Cameroon chimpanzee in Kom-Wum Forest Reserve, North-West Region, Cameroon}, doi = {10.26127/BTUOpen-6579}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-65797}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {Increased human activity, such as deforestation, is a major driver of biodiversity loss worldwide. In Cameroon, these activities could ultimately threaten the survival of the Nigeria-Cameroon chimpanzee, but knowledge of their abundance and ecology in the Kom - Wum Forest Reserve in Cameroon is still lacking. This research aimed to estimate the population size of this chimpanzee subspecies and assess threats, investigate nesting behaviour, identify suitable habitats, determine feeding habits and document the tools used for food acquisition. Research was conducted using line transects during two seasons: wet (May-September 2018) and dry (November 2019-March 2020). Population size and threats were assessed by georeferencing signs of chimpanzees and human activity along line transects. Nesting behaviour was investigated by recording the characteristics of nesting trees along line transects and mapping their distribution in ArcGIS. Suitable habitat was identified by relating chimpanzee presence signs to local environmental variables related to relief, vegetation and human impact using the Maximum Entropy Species Distribution Model (MaxEnt). Feeding habits were investigated by direct examination of chimpanzee faeces, and tool use was documented by observation and measurement of tools in situ. The reserve is home to up to 83 chimpanzees. Signs of chimpanzee activity were significantly higher in mature forest than in secondary forest, and above 1000 m than below 1000 m. Hunting was the main threat to chimpanzees, and the occurrence of chimpanzee signs decreased significantly with increasing human activity. Chimpanzees preferred tall, mature forest trees at higher elevations with slopes for nesting, and avoided areas near villages and bare land. Only 8\% of the study area was suitable chimpanzee habitat. Fruit dominated the chimpanzees' diet, but they also consumed leaves and fruit pith, especially during the dry season. There was also indirect evidence that chimpanzees used tools to consume driver ants (genus Dorylus). Seasonality significantly affected the size of tools used by chimpanzees for driver ant predation. They preferred to use thicker and shorter tools for driver ant predation during the rainy season, whereas longer and thinner tools were used during the dry season. The results of this research highlight the need to reduce poaching and deforestation to protect the remaining chimpanzee population and suitable habitat in the reserve and surrounding unprotected forest. High-elevation and mature forests are critical for chimpanzee conservation and should be a high priority for protection. This research has filled the knowledge gap on what little was known about the abundance and ecology of Nigeria-Cameroon chimpanzees.}, subject = {Chimpanzee abundance; Feeding ecology; Human disturbance; Habitat preferences; Nigeria-Cameroon chimpanzee; Schimpansenvorkommen; F{\"u}tterungs{\"o}kologie; Menschenverursachte St{\"o}rungen; Lebensraumpr{\"a}ferenzen; Nigeria-Kamerun-Schimpanse; Pan troglodytes elliotii; Reservat; Lebensraum; Ern{\"a}hrungsgewohnheit; St{\"o}rung; Verhaltensforschung}, language = {en} } @phdthesis{Franken2023, author = {Franken, Tim}, title = {Multi-objective optimization of stochastic engine models}, doi = {10.26127/BTUOpen-6633}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-66335}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {This thesis summarizes the author's developments of combustion models and multi-objective optimization methods for gasoline and diesel engines. The combustion models belong to the family of zero-dimensional stochastic reactor models introduced in the 1990s to improve the prediction of emissions with detailed chemistry in partially stirred reactors. The first part introduces the fundamentals of the physical and chemical models describing the combustion process. As a novelty, k-ε turbulence models were implemented in the stochastic reactor model to predict the turbulent time and length scales in gasoline and diesel engines. This development allowed an improvement of the models for convective heat transfer, fuel evaporation, gas exchange across the valves, turbulent flame propagation and crevice flow, which depend on the turbulent time and length scales. In the second part, the multi-objective optimization platform for automatic training of the stochastic reactor model is presented. The optimization method considers multiple operating points to find a set of model parameters that predict performance and emissions over the entire engine map. The Non-domination Sorting Genetic Algorithm II is combined with the stochastic reactor model and response surface models to find the best Pareto front. Multi-criteria decision making is used to select the best designs from the Pareto front. Finally, the third part of this thesis deals with the validation of the stochastic reactor model and the multi-objective optimization platform. For this purpose, experiments of two single-cylinder research engines with spark ignition, one passenger car engine with compression ignition and one heavy duty engine with compression ignition are used. For the spark ignition engines, a set of model parameters was found that predicts well the power and emissions over the whole engine map. The calculated turbulent kinetic energy, dissipation, and angular momentum follow the trends of the three-dimensional computational fluid dynamic simulations to a good approximation for various operating points. For the two compression ignition engines, the prediction of combustion progress and nitrogen oxide emissions are in good agreement with the experiments. Larger discrepancies were found for the prediction of carbon monoxide and unburned hydrocarbon. Optimization of the soot model parameters improves the prediction of soot mass for operating points throughout the engine map.}, subject = {Stochastic reactor model; Multi-objective optimization; Turbulence modelling; Emissions; Internal combustion engine; Stochastisches Reaktormodell; Multi-kriterielle Optimierung; Turbulenzmodellerierung; Emissionen; Verbrennungsmotor; Verbrennungsmotor; Abgasemission; Turbulenz; Stochastisches Modell; Optimierung}, language = {en} } @article{FrankenNetzerMaussetal., author = {Franken, Tim and Netzer, Corinna and Mauss, Fabian and Pasternak, Michal and Seidel, Lars and Borg, Anders and Lehtiniemi, Harry and Matrisciano, Andrea and Kulzer, Andre Casal}, title = {Multi-objective optimization of water injection in spark-ignition engines using the stochastic reactor model with tabulated chemistry}, publisher = {SAGE Publications}, address = {London, England}, issn = {1468-0874}, doi = {10.1177/1468087419857602}, abstract = {Water injection is investigated for turbocharged spark-ignition engines to reduce knock probability and enable higher engine efficiency. The novel approach of this work is the development of a simulation-based optimization process combining the advantages of detailed chemistry, the stochastic reactor model and genetic optimization to assess water injection. The fast running quasi-dimensional stochastic reactor model with tabulated chemistry accounts for water effects on laminar flame speed and combustion chemistry. The stochastic reactor model is coupled with the Non-dominated Sorting Genetic Algorithm to find an optimum set of operating conditions for high engine efficiency. Subsequently, the feasibility of the simulation-based optimization process is tested for a three-dimensional computational fluid dynamic numerical test case. The newly proposed optimization method predicts a trade-off between fuel efficiency and low knock probability, which highlights the present target conflict for spark-ignition engine development. Overall, the optimization shows that water injection is beneficial to decrease fuel consumption and knock probability at the same time. The application of the fast running quasi-dimensional stochastic reactor model allows to run large optimization problems with low computational costs. The incorporation with the Non-dominated Sorting Genetic Algorithm shows a well-performing multi-objective optimization and an optimized set of engine operating parameters with water injection and high compression ratio is found.}, subject = {Ottomotor; Water injection; Genetic optimization; Spark-ignition engine; Stochastic reactor model; Detailed chemistry; Wassereinspritzung; Prozessoptimierung; Stochastisches Modell}, language = {en} } @phdthesis{Frimpong2022, author = {Frimpong, Bernard Fosu}, title = {Analysis of the relationship between spatial urban expansion and temperature utilising remote sensing and GIS techniques in the Accra and Kumasi Metropolises in Ghana}, doi = {10.26127/BTUOpen-6073}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-60730}, school = {BTU Cottbus - Senftenberg}, year = {2022}, abstract = {Accra and Kumasi are the two major cities in Ghana. Spatial urban expansion has been experienced in transforming different non-urban Land Use Land Cover (LULC) types into urban/built-up areas with a potential direct relationship to temperature rise in the cities. Thus, this dissertation aims to establish the relationship between urban spatial expansion and temperature in Accra and Kumasi metropolis. Multi-source datasets such as remote sensing images, different GIS vector layers, reference maps and historical temperature datasets were used for this retrospective study. This research was grouped under three components: environmental science, environmental technology, as well as environmental management and planning. From the environmental science component, LULC maps were produced for different years to assess the trend of temporal change in the various LULC classes in the two metropolises. Remote sensing indices and land surface temperature were retrieved from the remote sensing images to determine their correlations. Temperature time series was analysed by calculating temperature indices and determining temporal trends to reveal changes in air temperature to detect urban warming and its impacts. From the environmental technology, the novel random forest algorithm was utilised to classify the satellite images of both cities since previous works have utilised other traditional classifiers. The satellite imageries were used for point-based estimation of temperature to determine Urban Heat Islands (UHIs) hotspots. For environmental management and planning, spatial urban expansion techniques were utilised to ascertain trends in urban/built-up areas, especially in both cities' sub-metropolitan zones. For prescient purposes, future LULC modelling was implemented to provide insights into the proportions of the various LULC changes in 2025. The analysis identified two salient findings: increased urban/built-up areas at the expense of agricultural and forestlands throughout the study period and the positive correlation between spatial urban expansion and temperature. This indicated warming up of urban temperature in both cities. The major findings in this dissertation provided evidence of how integrated datasets and research techniques can be utilised for LULC changes to determine the relationship between spatial urban expansion and temperature at local scales. Institutions such as metropolitan assemblies and policymakers may adopt the concepts demonstrated in this work to rapidly assess urban environments and investigate the relationship between spatial urban expansion and temperature.}, subject = {Spatial urban expansion; Temperature; Land Use Land Cover; Remote sensing; GIS; Urbane Expansion; Temperatur; Landnutzung; Landbedeckung; Fernerkundung; Ghana; Landnutzung; Großstadt; Temperatur; Fernerkundung; Geoinformationssystem}, language = {en} } @article{FrimpongKorantengOpoku2023, author = {Frimpong, Bernard Fosu and Koranteng, Addo and Opoku, Fosu Senior}, title = {Analysis of urban expansion and its impact on temperature utilising remote sensing and GIS techniques in the Accra metropolis in Ghana (1986-2022)}, doi = {10.1007/s42452-023-05439-z}, year = {2023}, abstract = {The Accra Metropolis of Ghana has experienced rapid urban expansion over the past decades. Agricultural and forest-lands have been transformed into urban/built-up areas. This study analysed urban expansion and its relationship with the temperature of Accra from 1986 to 2022. Multi-source datasets such as remote sensing (RS) and other ancillary data were utilised. Land use land cover (LULC) maps were produced employing the random forests classifier. Land surface temperature (LST) and selected d(RS) Indices were extracted. Regression techniques assessed the interplay between LST and remote sensing indices. The LULC maps revealed increasing trends in the urban/built-up areas at the expense of the other LULC types. The analysis from the LST and the RS indices revealed a direct relationship between temperature and urban/built-up areas and an inverse relationship between temperature and vegetation. Thus, spatial urban expansion has modified the urban temperature of Accra. The integrated utilisation of RS and GIS demonstrated to be an efficient approach for analysing and monitoring urban expansion and its relationship with temperature.}, subject = {Urban expansion; Change detection; Land use land cover; Regression; Remote sensing; St{\"a}dtische Expansion; Erkennung von Ver{\"a}nderungen; Landnutzung Landbedeckung; Temperatur; Fernerkundung; Accra; Stadt; Expansion; Landnutzung; Temperatur; Fernerkundung}, language = {en} } @article{FrimpongMolkenthinKoranteng2022, author = {Frimpong, Bernard Fosu and Molkenthin, Frank and Koranteng, Addo}, title = {Analysis of temperature variability utilising Mann-Kendall and Sen's slope estimator tests in the Accra and Kumasi metropolises in Ghana}, doi = {10.1186/s40068-022-00269-1}, year = {2022}, abstract = {Temperature variability may have direct and indirect impacts on the environments of the Accra and Kumasi Metropolises in Ghana. This study analysed temperature and trends in temperature in both cities using in-situ measurements from one meteorological station in both cities from 1986 to 2015. The temperature indices were computed using the RClimdex package from the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). The temperature time series was pre-whitened before the Mann-Kendall trend and Sen's slope estimator analysis were applied. Initial analysis revealed minimal variation in temperature in both cities. The results from the analysed temperature indices revealed an increase in warm days and a general rise in the minimum temperature compared to maximum temperatures. Mann Kendall and Sen's slope revealed significant trends in the annual and seasonal (dry and wet seasons) in minimum temperature in both cities. These might lead to an increased rate of heat-stressed diseases and an overall rise in urban warming in both cities. The analysis of temperature, indices and trends provided comprehensive insights into the temperature of Accra and Kumasi. The results highlight the essence of evaluating temperature indices and trends in light of Climate Change concerns. It is recommended that urban green and blue spaces should be incorporated into land use plans as these policy directions can aid regulate the temperature in both cities.}, subject = {Temperature variability; Mann-Kendall test; Sen's slope estimator; Accra; Kumasi; Temperaturvarabilit{\"a}t; Sen-Slope Sch{\"a}tzer; Accra; Kumasi; Temperatur; Schwankung}, language = {en} } @phdthesis{Frischke2006, author = {Frischke, S{\"o}ren}, title = {Simulationsbasierte Entscheidungsunterst{\"u}tzung bei der Gestaltung flexibler Produktionsbereiche auf taktischer Ebene}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-92}, school = {BTU Cottbus - Senftenberg}, year = {2006}, abstract = {Mit hoher Geschwindigkeit wechselnde qualitative und quantitative Marktanforderungen erfordern von Unternehmen geeignete Reaktionen. Die Umweltdynamik findet einerseits Eingang in die strategische Planung und f{\"u}hrt andererseits im Ausf{\"u}hrungssystem zu ungeplanter Turbulenz. Die taktische Ebene steht vor der Aufgabe, interne und externe Flexibilit{\"a}tsanforderungen und die Flexibilit{\"a}tspotentiale des Produktionsbereiches aufeinander abzustimmen. In der vorliegenden Arbeit wird ein in sich geschlossener Flexibilit{\"a}tsmanagementzyklus entwickelt. Durch die Erstellung hybrider Simulationsmodelle wird es m{\"o}glich, das Ausf{\"u}hrungssystem mit diskreten Systembestandteilen detailliert abzubilden ohne auf die Beschreibung selbst{\"a}ndigen Anpassungsverhaltens der Akteure durch Ausnutzung gegebener Handlungsspielr{\"a}ume in kontinuierlichen Modellbestandteilen verzichten zu m{\"u}ssen. Das Flexibilit{\"a}tspotential des Produktionssystems wird auf diese Weise sichtbar und kann analysiert werden.}, subject = {Flexible Fertigung; Produktionsplanung; Simulation; Strategische Planung; Simulationsmodelle; Flexible shop-floors; Strategic planning; Simulation; Production}, language = {de} } @phdthesis{Froehlich2003, author = {Fr{\"o}hlich, Robby}, title = {Zur allgemeing{\"u}ltigen Festlegung der sicherheitstechnischen Betriebsgrenzen von Alkoxilierungsreaktoren}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-000000356}, school = {BTU Cottbus - Senftenberg}, year = {2003}, abstract = {Alkoxilierungsreaktionen enthalten u.a. aufgrund der hohen Reaktionsenthalpie und der Stoffeigenschaften ein hohes Gef{\"a}hrdungspotential. Die Absicherung der Reaktoren hinsichtlich durchgehender Reaktionen kann durch konstruktive Maßnahmen sowie prozesstechnische Vorkehrungen erfolgen. Die Begrenzung der Konzentration des Epoxids als alternatives Schutzkonzept gewinnt zunehmend an Bedeutung, wobei selbst ein spontanes Durchgehen der Reaktion nicht zu einer Gef{\"a}hrdung f{\"u}hrt. Diese Arbeit ist prim{\"a}r auf die Anwendung der zuletzt angef{\"u}hrten Methode ausgerichtet. Ein experimenteller Ansatzes findet seine Grenzen in der Vielzahl der zu untersuchenden Stoffsystemkombinationen. Der in dieser Arbeit zugrunde gelegte theoretische Ansatz zielt demgegen{\"u}ber auf eine durchg{\"a}ngige und allgemeing{\"u}ltige Vorausberechnung der sicherheitstechnischen Betriebsgrenzen von Alkoxilierungsreaktoren unter Ber{\"u}cksichtigung der Design- und Betriebsparameter.}, subject = {Alkoxylierung; Exotherme Reaktion; Chemischer Reaktor; Betriebssicherheit; Prozessmodell; Sicherheitsgrenze von Reaktoren; Alkoxilierungsreaktion; Ethylenoxid; Propylenoxid; Fettstoff}, language = {de} } @techreport{FuegenschuhMuellenstedtSchmidt2019, author = {F{\"u}genschuh, Armin and M{\"u}llenstedt, Daniel and Schmidt, Johannes}, title = {Mission planning for unmanned aerial vehicles}, editor = {F{\"u}genschuh, Armin}, issn = {2627-6100}, doi = {10.26127/BTUOpen-4828}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-48285}, year = {2019}, abstract = {We formulate the mission planning problem for a meet of unmanned aerial vehicles (UAVs) as a mixed-integer nonlinear programming problem (MINLP). The problem asks for a selection of targets from a list to the UAVs, and trajectories that visit the chosen targets. To be feasible, a trajectory must pass each target at a desired maximal distance and within a certain time window, obstacles or regions of high risk must be avoided, and the fuel limitations must be obeyed. An optimal trajectory maximizes the sum of values of all targets that can be visited, and as a secondary goal, conducts the mission in the shortest possible time. In order to obtain numerical solutions to this model, we approximate the MINLP by a mixed-integer linear program (MILP), and apply a state-of-the-art solver (GUROBI) to the latter on a set of test instances.}, subject = {Mixed-integer nonlinear programming; Trajectory planning; Unmanned aerial vehicles; Linear approximation; Flugk{\"o}rper; Tourenplanung; Optimierung}, language = {en} }