@inproceedings{OPUS4-5715, title = {19th EEEIC International Conference on Environment and Electrical Engineering - Student Edition : Cottbus-Ostrava-Wrocław, June 2020}, editor = {Schwarz, Harald and Janik, Przemyslaw and Gono, Radomir and Lehmann, Dirk}, doi = {10.26127/BTUOpen-5715}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-57157}, year = {2020}, abstract = {In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development. Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg. The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.}, subject = {Energy resources; Energy system transformation; Elektrische Energie; Energietechnik; Energievorrat; Umweltbezogenes Management; Environmental management; Power quality; Energiequalit{\"a}t; Energieressourcen; Energietechnik; Energiewende; Umweltmanagement}, language = {en} } @inproceedings{OPUS4-5215, title = {19th EEEIC International Conference on Environment and Electrical Engineering - Student Edition : Cottbus-Ostrava-Wrocław, June 2020}, editor = {Schwarz, Harald and Janik, Przemysław and Gono, Radomir and Lehmann, Dirk}, isbn = {978-3-940471-55-0}, doi = {10.26127/BTUOpen-5215}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-52154}, year = {2020}, abstract = {In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development. Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg. The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.}, subject = {Energy resources; Environmental management; Power quality; Energy system transformation; Energieressourcen; Energiewende; Umweltmanagement; Energietechnik; Energiequalit{\"a}t; Elektrische Energie; Energietechnik; Energievorrat; Umweltbezogenes Management}, language = {en} } @phdthesis{Apte2020, author = {Apte, Anisha}, title = {A new analytical design method of ultra-low-noise voltage controlled VHF crystal oscillators and it's validation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-51386}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {The design of high Q oscillators, using Crystals at lower frequencies, (and dielectric resonators at much higher frequencies), has long been considered a black art. This may be due to the fact that a systematic approach with optimized design guideline for crystal oscillators could not be found after extensive literature search. In this dissertation, after analyzing the first crystal oscillator by W.G. Cady (1921), other high performance crystal oscillators will be discussed, analyzed and calculated. A single transistor crystal oscillator design as used by HP (Hewlett Packard) in one of their designs, the HP10811A is considered in this thesis for mathematical analysis and CAD (Computer aided Design) simulation. This was also measured on state-of-the-art signal source analyzer. After validation, this design is scaled to 100MHz, the frequency of interest for this dissertation. Though most designers use a single transistor based oscillator circuit, it is not an optimized design because of limited control over key design parameters such as loop gain, dc current etc. This dissertation is an attempt to overcome the limitation due to the single transistor circuit and to give a step by step procedure, explaining the significance of a two transistor design with thorough analysis and design simulation results. This two stage transistor circuit is also not yet a best solution in terms of phase noise performance and output power, and some add-on circuitry will be needed for an optimized performance. An important contribution of this work is to show that since the voltage gain is the ratio of the collector resistor and the emitter resistor, the performance is practically independent of the VHF transistor and gives better control over various parameters of the oscillator, in order to optimize the design. A grounded-base amplifier is then introduced and added for improving the isolation and the output power. Unlike most oscillators, that take the output from the collector, a novel concept introduced by Rohde [14], is incorporated here, where the crystal is used as a filter that is then connected to the grounded base amplifier, a technique which many companies have been using. This dissertation will show that this technique increases the output power without significantly affecting the phase noise. Such a validation is needed for better understanding and as per my knowledge, has not been done so far. For the oscillator, the tuning diode sensitivity and flicker noise contribution are also taken into consideration, by calibrating the mathematics and its validation is shown. Crystal resonators of the type AT and stress-compensated (SC) cut devices will be considered as they give the best performance. The one port Colpitts type oscillator is considered first and the two port two transistor design later. Both will need a post amplifier/buffer stage. A complete step by step design procedure for an optimized 100MHz crystal oscillator is then presented. For completeness, CAD Simulation and Experimental results are provided for 10 MHz, 128 MHz and 155 MHz VCO circuits.}, subject = {Quartz crystal; Crystal oscillator; Phase noise; Reference source; Voltage controlled; Quarzkristall; Kristalloszillator; Phasenrauschen; Referenzquelle; Spannungsgesteuert; Quarzoszillator; UKW; CAD}, language = {en} } @techreport{OclooFuegenschuhPamen2020, type = {Working Paper}, author = {Ocloo, Valentina E. and F{\"u}genschuh, Armin and Pamen, Olivier M.}, title = {A new mathematical model for a 3D container packing problem}, editor = {F{\"u}genschuh, Armin}, issn = {2627-6100}, doi = {10.26127/BTUOpen-5088}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-50880}, year = {2020}, abstract = {Wir betrachten das Problem der Einzelcontainerpackung eines Unternehmens, das seine Kunden bedienen muss, indem es zuerst die Produkte in Kartons legt und diese dann in einen Container l{\"a}dt. F{\"u}r dieses Problem entwickeln und l{\"o}sen wir ein lineares gemischt-ganzzahliges Modell. Unser Modell ber{\"u}cksichtigt geometrische Randbedingungen, beispielsweise {\"U}berlappungsverbote, Orientierungs-Bedingungen und Randbedingungen f{\"u}r die relative Positionierung der Kartons. Wir betrachten auch die Erweiterung des Modells durch die Integration der Schwerpunktsabweichung der Packung vom Containermittelpunkt. Das Modell wurde an einer großen Anzahl von realen Instanzen getestet, die bis zu 41 Kartons enthalten. In den meisten F{\"a}llen wurden optimale L{\"o}sungen erzielt bzw. nah-optimale L{\"o}sungen mit beweisbar kleiner Optimalit{\"a}tsl{\"u}cke.}, subject = {Container packing problem; Mixed-integer programming; Box orientation; Non-overlapping; Center of gravity deviation; Optimierungsproblem; Container; Lineare Optimierung; Logistik}, language = {en} } @phdthesis{Seserman2020, author = {Seserman, Diana-Maria}, title = {An empirical and simulation-based assessment of tree growth in temperate alley-cropping systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-51038}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {The potential of biomass generated from dedicated energy crops, used in short-rotation coppices (SRC), progressively grows recognition as a flexible primary source for the generation of energy, heat, fuel, and bio-based materials and chemicals. The alley-cropping systems (ACSs), which can integrate tree strips managed as SRC into agriculturally managed fields, are often regarded as an adaptable multi-crop land-use strategy that can provide ecological and economic benefits. The research aim of the present dissertation has focused on investigating the prospective implications of different site-specific conditions and scenarios on tree growth in ACSs with SRC, thus incorporating several experimental and simulation-based studies. For this, the ability of a process-oriented, eco-physiological tree growth model was investigated in order to (i) impute missing empirical data, thus securing a reliable repository of tree growth characteristics, (ii) simulate the tree growth in terms of woody biomass production in strong relation to the interactions with adjacent crops and their respective resource capture, (iii) predict and evaluate the tree growth sensitivity to prospective climate changes, thus performing risk assessments for the near and distant future, and (iv) derive and assess the land equivalent ratio (LER) and gross energy yield for different climatic, soil, and management scenarios. The findings have corroborated the potential tree growth vulnerability to prospective climatic changes, particularly to changes in water availability, and have underlined the importance of coping management strategies in SRC for forthcoming risk assessments and adaptation scenarios. Both LER and gross energy yields had resulted in a convex curve where the maximum values were achieved when either the tree or crop component was dominant (>75\% of the land area) and minimum when these components shared similar proportions of land area. Collectively, the implications of different site-specific conditions and scenarios on tree growth in ACSs with SRC have been investigated in order to improve the decision-making, optimization, and adaptation of such systems. Last but not least, this dissertation has emphasized the considerable potential of modelling approaches in ACSs, as they can impute missing data from scarce available data and simulate tree and crop yields for specific site-conditions in a non-intrusive, inexpensive, and prompt way while supporting early site-setup planning.}, subject = {Agroforestry; Land-use efficiency; Biomass; Statistics; Yield-SAFE; Agroforstwirtschaft; Biomasse; Effizienz der Landnutzung; Statistik; Alley cropping; Pflanzlicher Rohstoff; Ressourceneffizienz; Pflanzenwachstum; Modell}, language = {en} } @phdthesis{Alzagameem2020, author = {Al-zagameem, Abla}, title = {Antioxidant and antimicrobial properties of lignin and lignin-based composites for active food packaging applications}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-53024}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {Due to the use of fossil fuel resources, many environmental problems have been increasingly growing. Thus, the recent research focuses on the use of environment friendly materials from sustainable feedstocks for future fuels, chemicals, fibers and polymers. Lignocellulosic biomass has become the raw material of choice for these new materials. Recently, the research has focused on using lignin as a substitute material in many industrial applications. The antiradical and antimicrobial activity of lignin and lignin-based films are both of great interest for applications such as food packaging additives. DPPH assay was used to determine the antioxidant activity of Kraft lignin compared to Organosolv lignins from different biomasses. The purification procedure of Kraft lignin showed that double-fold selective extraction is the most efficient confirmed by UV-Vis, FTIR, HSQC, 31PNMR, SEC, and XRD. The antioxidant capacity was discussed regarding the biomass source, pulping process, and degree of purification. Lignin obtained from industrial black liquor are compared with beech wood samples: Biomass source influences the DPPH inhibition (softwood > grass) and the TPC (softwood < grass). DPPH inhibition affected by the polarity of the extraction solvent. Following the trend: ethanol > diethylether > acetone. Reduced polydispersity has positive influence on the DPPH inhibition. Storage decreased the DPPH inhibition but increased the TPC values. The DPPH assay was also used to discuss the antiradical activity of HPMC/lignin and HPMC/lignin/chitosan films. In both binary (HPMC/lignin) and ternary (HPMC/lignin/chitosan) systems the 5\% addition showed the highest activity and the highest addition had the lowest. Both scavenging activity and antimicrobial activity are dependent on the biomass source; Organosolv of softwood > Kraft of softwood > Organosolv of grass. Lignins and lignin-containing films showed high antimicrobial activities against Gram-positive and Gram-negative bacteria at 35 °C and at low temperatures (0-7 °C). Purification of Kraft lignin has a negative effect on the antimicrobial activity while storage has positive effect. The lignin leaching in the produced films affected the activity positively and the chitosan addition enhances the activity for both Gram-positive and Gram-negative bacteria. Testing the films against food spoilage bacteria that grow at low temperatures revealed the activity of the 30\% addition on HPMC/L1 film against both B. thermosphacta and P. fluorescens while L5 was active only against B. thermosphacta. In HPMC/lignin/chitosan films, the 5\% addition exhibited activity against both food spoilage bacteria.}, subject = {Lignin; Bioactivity; Food packaging; Lignin; Bioaktivit{\"a}t; Lebensmittelverpackungen; Lignin; Bioaktive Verbindung; Kunststoffverpackung; Antioxidans}, language = {en} } @phdthesis{MedinaMendez2020, author = {Medina Mendez, Juan Ali}, title = {Application of the One-Dimensional Turbulence model to electrohydrodynamically enhanced internally forced convective flows}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-53388}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {This thesis is an attempt to assess some of the effects that electroquasistatic body forces exert on turbulent internally forced convective flows. In order to do that, a stochastic turbulence model is employed, namely, the One-Dimensional Turbulence (ODT) model. The reduced dimensionality of ODT demands a reduction of the Navier-Stokes equations (and in this case, also the Maxwell equations), into a 1-D system. This is done by performing an asymptotic analysis in terms of the nondimensional numbers of the flow. Also, a validation step due to the relative novel character of the cylindrical ODT formulation is done for an incompressible and constant properties flow regime and a variable density flow regime. The validation is presented for both the temporal (T-ODT) and a novel spatial (S-ODT) formulation in both planar and cylindrical geometries. Results in the constant property case show that wall normal (and radial) profiles, in both the T-ODT and S-ODT formulations, show good agreement with each other and to the data of Direct Numerical Simulations (DNSs). For the evaluated variable density heated pipe flow, gradients at the wall can be better reproduced with S-ODT. After validating the model, ODT is applied first into a planar configuration which emulates the flow in a wire-plate Electrostatic Precipitator (ESP). For this flow, the additional input energy due to the electroquasistatic body force has an effect on the modification of the bulk velocity, and subsequently, the skin friction coefficient. Some qualitative DNS trends are confirmed with ODT, such as the localized increase of the Reynolds stress, as a consequence of increased eddy activity close to the discharge electrodes. Next, the results of ODT simulations in a cylindrical wire-tube ESP are presented. Here, ODT results are compared to experimental results. ODT results for global integral quantities such as the streamwise pressure gradient and the Nusselt number enhancement ratio are able to match in a reasonable way the experimental results. The competing relevance between the EHD contribution to turbulence by momentum, and by affecting the temperature and density due to the Joule heating effect is also analyzed, showing the leading order relevance of the former one. Specifically for the Nusselt number results, the sensitivity of the EHD flow to transition effects is shown to be very significant. This thesis may open the door to a vast new field of phenomena which can not only serve for the further validation of the ODT model against DNSs or experiments, but also for the real use of ODT in applications which are so far inaccessible for traditional DNSs.}, subject = {EHD; ODT; Forced convection; Turbulente Str{\"o}mung; Numerische Str{\"o}mungssimulation; Elektrohydrodynamik; Abscheider; Turbulenzmodell}, language = {en} } @phdthesis{Buechner2020, author = {B{\"u}chner, Steffen}, title = {Applying the stream-processing paradigm to ultra high-speed communication systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-52462}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {In the last 30 years, communication became one of the most important pillars of our civilization. Every day terabytes of information are moved wired and wireless between computers. In order to transport this amount of data, researchers and industry increase the data rates of the underlying communication networks with impressive speed. However, such ultra-high data rates are unavailable at the communication endpoints. One reason why ultra-high data rates are still not available for the communication endpoints is their inability to handle the protocol processing at this data rate. In order to enable communication endpoints to process high-volume data streams, the protocol processing has to be parallelized and optimized on all processing levels. However, parallelization and optimization are cumbersome tasks, which are further complicated as the protocol processing is traditionally carried out by the operating system. This thesis aims at circumventing these problems by moving the protocol processing into external processing hardware and interpreting communication protocols as stream processing problems. In order to achieve ultra-high data rates at the communication endpoints, a protocol stream processing design approach was developed and evaluated. The design process is separated into implementation, soft real-time analysis, parallelization, and mapping steps, which allow a scalable protocol implementation without paradigm changes. Furthermore, a data link protocol for 100 Gbit/s wireless was developed and implemented with the new stream processing design concept, in order to show its feasibility. The data link protocol is configurable for different communication conditions and easy to parallelize by providing different granularities of packets. The proposed design-process has shown to be suitable for uncovering bottlenecks and helping with debugging the individual stages of the protocol.}, subject = {Stream processing; Ultra high speed communication systems; Communication protocols; Wireless communication; End2End100; Stromverarbeitung; Ultra-Hoch-Geschwindigkeits-Kommunikationssysteme; Kommunikationsprotokolle; Drahtlose Kommunikation; Kommunikationsprotokoll; Protokollverarbeitung ; Hochgeschwindigkeitskommunikation; End2End100}, language = {en} } @techreport{GnegelFuegenschuh2020, type = {Working Paper}, author = {Gnegel, Fabian and F{\"u}genschuh, Armin}, title = {Branch-and-refine for solving time-dependent problems}, editor = {F{\"u}genschuh, Armin}, issn = {2627-6100}, doi = {10.26127/BTUOpen-5199}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-51995}, year = {2020}, abstract = {Einer der Standardans{\"a}tze zur L{\"o}sung zeitabh{\"a}ngiger diskreter Optimierungsprobleme, wie z.B. das Problem des Handlungsreisenden mit Zeitfenstern oder das K{\"u}rzeste Wege Problem mit Zeitfenstern, ist die Herleitung einer sogenannten zeitindizierten Formulierung. Wenn dem Problem eine Struktur zu Grunde liegt, die durch einen Graphen beschrieben werden kann, basiert die zeitindizierte Formulierung normalerweise auf einem anderen, erweiterten Graphen, der in der Literatur als zeitexpandierter Graph bezeichnet wird. Der zeitexpandierte Graph kann oft so generiert werden, dass alle Zeitbeschr{\"a}nkungen bereits aufgrund seiner Topologie erf{\"u}llt sind und somit Algorithmen f{\"u}r die entsprechende zeitunabh{\"a}ngige Variante angewendet werden k{\"o}nnen. Der Nachteil dieses Ansatzes ist, dass die Mengen der Ecken und B{\"o}gen des zeitexpandierten Graphen viel gr{\"o}ßer sind als die des urspr{\"u}nglichen Graphen. In neueren Arbeiten hat sich jedoch gezeigt, dass f{\"u}r viele praktische Anwendungen eine partielle Expandierung des Graphen, die m{\"o}glicherweise zeitunm{\"o}gliche Pfade zul{\"a}sst, oft ausreicht, um eine beweisbar optimale L{\"o}sung zu finden. Diese Ans{\"a}tze verfeinern iterativ den urspr{\"u}nglichen Graphen und l{\"o}sen in jeder Iteration eine Relaxierung der zeitexpandierten Formulierung. Wenn die L{\"o}sung der aktuellen Relaxation alle Zeitbeschr{\"a}nkungen erf{\"u}llt, kann daraus eine optimale L{\"o}sung abgeleitet werden, und der Algorithmus terminiert. In dieser Arbeit stellen wir neue Ideen vor, die das {\"U}bertragen von Informationen {\"u}ber die optimale L{\"o}sung eines gr{\"o}beren Graphen zu einem verfeinerten Graphen erm{\"o}glichen und zeigen, wie diese in Algorithmen verwendet werden k{\"o}nnen. Genauer gesagt stellen wir einen neuen Algorithmus zur L{\"o}sung von MILP-Formulierungen (Mixed Integer Linear Program) von zeitabh{\"a}ngigen Problemen vor, der es erm{\"o}glicht, die Graphenverfeinerung w{\"a}hrend der Untersuchung des Branch-and-Bound Baums durchzuf{\"u}hren, anstatt jedes Mal neu zu starten, wenn die optimale L{\"o}sung sich als nicht zul{\"a}ssig herausgestellt hat. Um die praktische Relevanz dieses Algorithmus zu demonstrieren, pr{\"a}sentieren wir Ergebnisse von numerische Experimenten seiner Anwendung auf das K{\"u}rzeste Wege Problem mit Zeitfenstern und das Problem des Handlungsreisenden mit Zeitfenstern.}, subject = {Graphenverfeinerung; Branch-and-Bound; K{\"u}rzeste Wege Problem mit Zeitfenstern; Problem des Handlungsreisenden mit Zeitfenstern; Graph refinement; Branch-and-bound; Shortest path problem with time-windows; Travelling salesman problem with time-windows; Branch-and-Bound-Methode; K{\"u}rzester-Weg-Problem; Travelling-salesman-Problem}, language = {en} } @inproceedings{Simon2020, author = {Simon, Sylvio}, title = {Conference proceedings of the 4th international conference on energy supply and energy efficiency and "5 years NESEFF"}, editor = {Simon, Sylvio and Danneberg, Nina}, isbn = {978-3-940471-59-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-53808}, year = {2020}, abstract = {Climate change, CO2 reduction, resource efficiency are only 3 current keywords that describe the current industrial-economic situation. In order to influence climate change effectively, the conversion of supply systems with technically usable forms of energy must succeed in the next decade. The international network founded in Baku in 2015 bundles research activities in the broad field of energy supply and energy efficiency. Discuss current research approaches and results with scientists and experts from renowned universities and follow Azerbaijan's efforts to implement the energy revolution.}, subject = {Rollers; Climate change; Energy efficiency; Energy resources; Energy management; Tragrollen; Energieeffizienz; Klimawandel; Energieressourcen; Energiemanagement; Klimawandel; Energiemanagement; Energieeffizienz; Energieversorgung}, language = {en} }