@phdthesis{Ermeydan2014, author = {Ermeydan, Mahmut Ali}, title = {Wood cell wall modification with hydrophobic molecules}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71325}, school = {Universit{\"a}t Potsdam}, year = {2014}, abstract = {Wood is used for many applications because of its excellent mechanical properties, relative abundance and as it is a renewable resource. However, its wider utilization as an engineering material is limited because it swells and shrinks upon moisture changes and is susceptible to degradation by microorganisms and/or insects. Chemical modifications of wood have been shown to improve dimensional stability, water repellence and/or durability, thus increasing potential service-life of wood materials. However current treatments are limited because it is difficult to introduce and fix such modifications deep inside the tissue and cell wall. Within the scope of this thesis, novel chemical modification methods of wood cell walls were developed to improve both dimensional stability and water repellence of wood material. These methods were partly inspired by the heartwood formation in living trees, a process, that for some species results in an insertion of hydrophobic chemical substances into the cell walls of already dead wood cells, In the first part of this thesis a chemistry to modify wood cell walls was used, which was inspired by the natural process of heartwood formation. Commercially available hydrophobic flavonoid molecules were effectively inserted in the cell walls of spruce, a softwood species with low natural durability, after a tosylation treatment to obtain "artificial heartwood". Flavonoid inserted cell walls show a reduced moisture absorption, resulting in better dimensional stability, water repellency and increased hardness. This approach was quite different compared to established modifications which mainly address hydroxyl groups of cell wall polymers with hydrophilic substances. In the second part of the work in-situ styrene polymerization inside the tosylated cell walls was studied. It is known that there is a weak adhesion between hydrophobic polymers and hydrophilic cell wall components. The hydrophobic styrene monomers were inserted into the tosylated wood cell walls for further polymerization to form polystyrene in the cell walls, which increased the dimensional stability of the bulk wood material and reduced water uptake of the cell walls considerably when compared to controls. In the third part of the work, grafting of another hydrophobic and also biodegradable polymer, poly(ɛ-caprolactone) in the wood cell walls by ring opening polymerization of ɛ-caprolactone was studied at mild temperatures. Results indicated that polycaprolactone attached into the cell walls, caused permanent swelling of the cell walls up to 5\%. Dimensional stability of the bulk wood material increased 40\% and water absorption reduced more than 35\%. A fully biodegradable and hydrophobized wood material was obtained with this method which reduces disposal problem of the modified wood materials and has improved properties to extend the material's service-life. Starting from a bio-inspired approach which showed great promise as an alternative to standard cell wall modifications we showed the possibility of inserting hydrophobic molecules in the cell walls and supported this fact with in-situ styrene and ɛ-caprolactone polymerization into the cell walls. It was shown in this thesis that despite the extensive knowledge and long history of using wood as a material there is still room for novel chemical modifications which could have a high impact on improving wood properties.}, language = {en} } @misc{ErlerRiebeBeitzetal.2019, author = {Erler, Alexander and Riebe, Daniel and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Gebbers, Robin}, title = {Soil Nutrient Detection for Precision Agriculture Using Handheld Laser-Induced Breakdown Spectroscopy (LIBS) and Multivariate Regression Methods (PLSR, Lasso and GPR)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {815}, issn = {1866-8372}, doi = {10.25932/publishup-44418}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-444183}, pages = {19}, year = {2019}, abstract = {Precision agriculture (PA) strongly relies on spatially differentiated sensor information. Handheld instruments based on laser-induced breakdown spectroscopy (LIBS) are a promising sensor technique for the in-field determination of various soil parameters. In this work, the potential of handheld LIBS for the determination of the total mass fractions of the major nutrients Ca, K, Mg, N, P and the trace nutrients Mn, Fe was evaluated. Additionally, other soil parameters, such as humus content, soil pH value and plant available P content, were determined. Since the quantification of nutrients by LIBS depends strongly on the soil matrix, various multivariate regression methods were used for calibration and prediction. These include partial least squares regression (PLSR), least absolute shrinkage and selection operator regression (Lasso), and Gaussian process regression (GPR). The best prediction results were obtained for Ca, K, Mg and Fe. The coefficients of determination obtained for other nutrients were smaller. This is due to much lower concentrations in the case of Mn, while the low number of lines and very weak intensities are the reason for the deviation of N and P. Soil parameters that are not directly related to one element, such as pH, could also be predicted. Lasso and GPR yielded slightly better results than PLSR. Additionally, several methods of data pretreatment were investigated.}, language = {en} } @phdthesis{Erler2020, author = {Erler, Alexander}, title = {Entwicklung von online-Detektionsverfahren f{\"u}r landwirtschaftlich relevante Analyten}, doi = {10.25932/publishup-47340}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473406}, school = {Universit{\"a}t Potsdam}, pages = {viii, 123}, year = {2020}, abstract = {Die Entwicklung nachhaltiger Bewirtschaftungs- und Produktionsmethoden ist eine der zentralen Fragestellungen der modernen Agrarwirtschaft. Die vorliegende Arbeit besch{\"a}ftigt sich mit zwei Forschungsthemen, die das Konzept Nachhaltigkeit beinhalten. In beiden F{\"a}llen werden analytische Grundlagen f{\"u}r die Entwicklung entsprechender landwirtschaftlicher Arbeitsmethoden gelegt. Das erste Thema ist an den sogenannten Pr{\"a}zisionsackerbau angelehnt. Bei diesem wird die Bearbeitung von Agrarfl{\"a}chen ortsabh{\"a}ngig ausgef{\"u}hrt. Das heißt, die Ausbringung von Saatgut, D{\"u}nger, Bew{\"a}sserung usw. richtet sich nach den Eigenschaften des jeweiligen Standortes und wird nicht pauschal gleichm{\"a}ßig {\"u}ber ein ganzes Feld verteilt. Voraussetzung hierf{\"u}r ist eine genaue Kenntnis der Bodeneigenschaften. In der vorliegenden Arbeit sollten diese Parameter mittels der analytischen Technik der Laser-induzierten Breakdown Spektroskopie (LIBS), die eine Form der Elementaranalyse darstellt, bestimmt werden. Bei den hier gesuchten Bodeneigenschaften handelte es sich um die Gehalte von N{\"a}hrstoffen sowie einige sekund{\"a}re Parameter wie den Humusanteil, den pH-Wert und den pflanzenverf{\"u}gbaren Anteil einzelner N{\"a}hrstoffe. Diese Eigenschaften wurden durch etablierte Referenzanalysen bestimmt. Darauf aufbauend wurden die Messergebnissen der LIBS-Untersuchungen durch verschiedene Methoden der sogenannten multivariaten Datenanalyse (MVA) ausgewertet. Daraus sollten Modelle zur Vorhersage der Bodenparameter in zuk{\"u}nftigen LIBS-Messungen erarbeitet werden. Die Ergebnisse dieser Arbeit zeigten, dass mit der Kombination von LIBS und MVA s{\"a}mtliche Bodenparameter erfolgreich vorhergesagt werden konnten. Dies beinhaltete sowohl die tats{\"a}chlich messbaren Elemente als auch die sekund{\"a}ren Eigenschaften, welche durch die MVA mit den Elementgehalten in Zusammenhang gebracht wurden. Das zweite Thema besch{\"a}ftigt sich mit der Vermeidung von Verlusten durch Sch{\"a}dlingsbefall bei der Getreidelagerung. Hier sollten mittels der Ionenmobilit{\"a}tsspektrometrie (IMS) Schimmelpilzkontaminationen detektiert werden. Dabei wurde nach den fl{\"u}chtigen Stoffwechselprodukten der Pilze gesucht. Die durch Referenzmessungen mit Massenspektrometern identifizierten Substanzen konnten durch IMS im Gasvolumen {\"u}ber den Proben, dem sogenannten Headspace, nachgewiesen werden. Dabei wurde nicht nur die Anwesenheit einer Kontamination festgestellt, sondern diese auch charakterisiert. Die freigesetzten Substanzen bildeten spezifische Muster, anhand derer die Pilze identifiziert werden konnten. Hier wurden sowohl verschiedene Gattungen als auch einzelne Arten unterschieden. Die Messungen fanden auf verschiedenen N{\"a}hrb{\"o}den statt um den Einfluss dieser auf die Stoffwechselprodukte zu beobachten. Auch die sekund{\"a}ren Stoffwechselprodukte der Schimmelpilze, die Mykotoxine, konnten durch IMS detektiert werden. Beide in dieser Arbeit vorgestellten Forschungsthemen konnten erfolgreich abgeschlossen werden. Sowohl LIBS als auch IMS erwiesen sich f{\"u}r den Nachweis der jeweiligen Analyten als geeignet, und der Einsatz moderner computergest{\"u}tzter Auswertemethoden erm{\"o}glichte die genaue Charakterisierung der gesuchten Parameter. Beide Techniken k{\"o}nnen in Form von mobilen Ger{\"a}ten verwendet werden und zeichnen sich durch eine schnelle und sichere Analyse aus. In Kombination mit entsprechenden Modellen der MVA sind damit alle Voraussetzungen f{\"u}r Vor-Ort-Untersuchungen und damit f{\"u}r den Einsatz in der Landwirtschaft erf{\"u}llt.}, language = {de} } @techreport{ErhardtGeskeRichter2022, author = {Erhardt, Nick and Geske, Anna and Richter, Dirk}, title = {Zwischenbericht}, doi = {10.25932/publishup-54771}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-547714}, pages = {31}, year = {2022}, abstract = {In Deutschland leben aktuell rund 1,8 Mio. als schutzsuchend registrierte Menschen mit Fluchterfahrung, deren Integration eine gesamtgesellschaftliche Aufgabe darstellt. Viele dieser Personen sind hoch qualifiziert und arbeiteten in ihrem Herkunftsland als Lehrkr{\"a}fte. Das Qualifizierungsprogramm Lehrkr{\"a}fte Plus erm{\"o}glicht migrierten Lehrkr{\"a}ften den beruflichen Wiedereinstieg in Deutschland zu erlangen. Da bislang wenig wissenschaftliche Evidenz zur Wirksamkeit solcher Qualifizierungsprogramme vorliegt, wird das Programm Lehrkr{\"a}fte Plus durch ein Forschungsvorhaben der Universit{\"a}t Potsdam untersucht. In dem vorliegenden Zwischenbericht werden erste Ergebnisse der wissenschaftlichen Begleitforschung auf Basis der ersten Erhebungen vorgestellt.}, language = {de} } @incollection{Erfurt2005, author = {Erfurt, J{\"u}rgen}, title = {Zweisprachige Alphabetisierung im R{\"a}derwerk politischer und wissenschaftlicher Diskurse}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10023}, publisher = {Universit{\"a}t Potsdam}, year = {2005}, language = {de} } @phdthesis{Eren2024, author = {Eren, Enis Oğuzhan}, title = {Covalent anode materials for high-energy sodium-ion batteries}, doi = {10.25932/publishup-62258}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-622585}, school = {Universit{\"a}t Potsdam}, pages = {xi, 153}, year = {2024}, abstract = {The reliance on fossil fuels has resulted in an abnormal increase in the concentration of greenhouse gases, contributing to the global climate crisis. In response, a rapid transition to renewable energy sources has begun, particularly lithium-ion batteries, playing a crucial role in the green energy transformation. However, concerns regarding the availability and geopolitical implications of lithium have prompted the exploration of alternative rechargeable battery systems, such as sodium-ion batteries. Sodium is significantly abundant and more homogeneously distributed in the crust and seawater, making it easier and less expensive to extract than lithium. However, because of the mysterious nature of its components, sodium-ion batteries are not yet sufficiently advanced to take the place of lithium-ion batteries. Specifically, sodium exhibits a more metallic character and a larger ionic radius, resulting in a different ion storage mechanism utilized in lithium-ion batteries. Innovations in synthetic methods, post-treatments, and interface engineering clearly demonstrate the significance of developing high-performance carbonaceous anode materials for sodium-ion batteries. The objective of this dissertation is to present a systematic approach for fabricating efficient, high-performance, and sustainable carbonaceous anode materials for sodium-ion batteries. This will involve a comprehensive investigation of different chemical environments and post-modification techniques as well. This dissertation focuses on three main objectives. Firstly, it explores the significance of post-synthetic methods in designing interfaces. A conformal carbon nitride coating is deposited through chemical vapor deposition on a carbon electrode as an artificial solid-electrolyte interface layer, resulting in improved electrochemical performance. The interaction between the carbon nitride artificial interface and the carbon electrode enhances initial Coulombic efficiency, rate performance, and total capacity. Secondly, a novel process for preparing sulfur-rich carbon as a high-performing anode material for sodium-ion batteries is presented. The method involves using an oligo-3,4-ethylenedioxythiophene precursor for high sulfur content hard carbon anode to investigate the sulfur heteroatom effect on the electrochemical sodium storage mechanism. By optimizing the condensation temperature, a significant transformation in the materials' nanostructure is achieved, leading to improved electrochemical performance. The use of in-operando small-angle X-ray scattering provides valuable insights into the interaction between micropores and sodium ions during the electrochemical processes. Lastly, the development of high-capacity hard carbon, derived from 5-hydroxymethyl furfural, is examined. This carbon material exhibits exceptional performance at both low and high current densities. Extensive electrochemical and physicochemical characterizations shed light on the sodium storage mechanism concerning the chemical environment, establishing the material's stability and potential applications in sodium-ion batteries.}, language = {en} } @phdthesis{Erdmann2005, author = {Erdmann, Thorsten}, title = {Stochastic dynamics of adhesion clusters under force}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5564}, school = {Universit{\"a}t Potsdam}, year = {2005}, abstract = {Adhesion of biological cells to their environment is mediated by two-dimensional clusters of specific adhesion molecules which are assembled in the plasma membrane of the cells. Due to the activity of the cells or external influences, these adhesion sites are usually subject to physical forces. In recent years, the influence of such forces on the stability of cellular adhesion clusters was increasingly investigated. In particular, experimental methods that were originally designed for the investigation of single bond rupture under force have been applied to investigate the rupture of adhesion clusters. The transition from single to multiple bonds, however, is not trivial and requires theoretical modelling. Rupture of biological adhesion molecules is a thermally activated, stochastic process. In this work, a stochastic model for the rupture and rebinding dynamics of clusters of parallel adhesion molecules under force is presented. In particular, the influence of (i) a constant force as it may be assumed for cellular adhesion clusters is investigated and (ii) the influence of a linearly increasing force as commonly used in experiments is considered. Special attention is paid to the force-mediated cooperativity of parallel adhesion bonds. Finally, the influence of a finite distance between receptors and ligands on the binding dynamics is investigated. Thereby, the distance can be bridged by polymeric linker molecules which tether the ligands to a substrate.}, subject = {Biophysik}, language = {en} } @article{ErdmannRatzlaff2017, author = {Erdmann, Melinda and Ratzlaff, Olaf}, title = {Wahrnehmung und Heterogenit{\"a}t von Fach- und Lehramtsstudierenden im Kontext von Lehrveranstaltungen}, series = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, journal = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, number = {3}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-399-2}, issn = {2192-1075}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-399723}, pages = {181 -- 196}, year = {2017}, language = {de} } @article{Erdmann2019, author = {Erdmann, Melinda}, title = {Alles auf Anfang! Und wie oft?}, series = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, journal = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-452-4}, issn = {2192-1075}, doi = {10.25932/publishup-42836}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428361}, pages = {59 -- 77}, year = {2019}, language = {de} } @article{Erdmann2019, author = {Erdmann, Melinda}, title = {Existieren migrationsspezifische Problemlagen in der Studieneingangsphase?}, series = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, journal = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-452-4}, issn = {2192-1075}, doi = {10.25932/publishup-42837}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428377}, pages = {103 -- 120}, year = {2019}, language = {de} } @article{ErdmannKoziolMeissner2019, author = {Erdmann, Kathrin and Koziol, Matthias and Meißner, Marlen}, title = {College+}, series = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, journal = {Alles auf Anfang! Befunde und Perspektiven zum Studieneingang}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-452-4}, issn = {2192-1075}, doi = {10.25932/publishup-42857}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428570}, pages = {313 -- 323}, year = {2019}, language = {de} } @misc{Erdmann2015, author = {Erdmann, Julius}, title = {Semiotics of Pictorial Signs on Social Networking Sites}, series = {Postprints der Universit{\"a}t Potsdam : Philosophische Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Philosophische Reihe}, number = {118}, issn = {1866-8380}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-96484}, pages = {16}, year = {2015}, abstract = {The paper aims at considering characteristics from one field of contemporary visual studies that has for a long time been neglected in academic research: Pictorial signs on Social Network Sites (SNS) are an outstanding class of semiotic resources that is greatly shaped by processes of technological and collective sign production and distribution. A brief examination of the scholarly research on the pragmatics and semiotics of pictorial signs on SNS shows that the heterogeneity of visual signs is often neglected and that it mostly concentrates on one aspect of these pictorial signs: their technological production or their purpose for individual self-disclosure. The paper therefore considers the semiosis of pictorial signs on SNS in a holistic perspective as one the one hand produced by individual and collective meaning making as well as on the other hand a product of technological framing. It therefore develops a techno-semiotic pragmatic account that takes into consideration both processes. Starting from a prominent class of pictorial signs on SNS during Tunisian Revolution, the Tunisian Flag graphics, the paper than shows that communicative and social interaction functions on the graphic interface of SNS ('like'-function, sharing and commenting option) are not only directly inscribed into the pictorial frame, but also greatly influence the reading of a pictorial sign. The location of images on the SNS' interface has an impact on its meaning and on the social functions of a pictorial sign, as profile pictures are directly linked to the online identity of the user. Through technological sign processing, the polysemy of the image is reduced. We therefore consider the images on the one hand as individual self-narratives and on the other as instances of SNS' visual culture that brings out dominant visual codes but also allows social and political movements to spread.}, language = {de} } @article{ErdmannWeber2015, author = {Erdmann, Dominik and Weber, Jutta}, title = {Nachlassgeschichten}, series = {HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies}, volume = {XVI}, journal = {HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies}, number = {31}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, doi = {10.18443/223}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-88997}, pages = {60 -- 79}, year = {2015}, abstract = {Der Artikel schildert die Geschichte verschiedener Teile des Manuskriptnachlasses Alexander von Humboldts, die sich heute in der Staatsbibliothek zu Berlin - Preußischer Kulturbesitz (SBB) und in der Biblioteka Jagiellońska in Krakau (BJ) befinden. Dabei wird insbesondere auf den unterschiedlichen ‚Quellenwert' der drei großen Nachlassabteilungen - der amerikanischen Reisetageb{\"u}cher, der Kollektaneen zum Kosmos (beide SBB) und dem sogenannten Nachlass Alexander von Humboldt (BJ) - eingegangen.}, language = {de} } @article{ErdmannThomas2015, author = {Erdmann, Dominik and Thomas, Christian}, title = {„… zu den wunderlichsten Schlangen der Gelehrsamkeit zusammengegliedert"}, series = {HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies}, volume = {XV}, journal = {HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies}, number = {28}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-84054}, pages = {34 -- 45}, year = {2015}, abstract = {Alexander von Humboldts 1827/28 gehaltene Kosmos-Vortr{\"a}ge stellen ebenso einen kanonischen Bezugspunkt wie einen weißen Fleck in der Rezeption seines Schaffens dar. Zahlreiche Deutungen basieren auf lediglich zwei unkommentierten Leseausgaben von Collegheften anonym gebliebener Zuh{\"o}rer Humboldts. Seine 2009 wiedergefundenen eigenh{\"a}ndigen Vorlesungsmanuskripte versprechen, diese schmale Quellenbasis zu erweitern. Alfred Dove hatte bereits 1872 auf ihre Existenz verwiesen und interpretierte sie damals als Nukleus der schriftlichen Ausarbeitung des Kosmos. Diese Sichtweise hat sich in der Rezeption gehalten, w{\"a}hrend die Materialien, die Dove beschrieb, in Vergessenheit gerieten. Der Artikel stellt anhand ausgew{\"a}hlter Beispiele die Vorlesungsmanuskripte Humboldts und Nachschriften seiner Zuh{\"o}rer in ihrem Zusammenhang vor, entwickelt die These von der Eigenst{\"a}ndigkeit der sogenannten Kosmos-Vortr{\"a}ge gegen{\"u}ber dem f{\"u}nfb{\"a}ndigen Kosmos und umreißt die wichtigsten Ziele und Inhalte der geplanten digitalen Edition.}, language = {de} } @misc{ErdelenLaschewskyRingsdorfetal.1989, author = {Erdelen, C. and Laschewsky, Andr{\´e} and Ringsdorf, H. and Schneider, J. and Schuster, A.}, title = {Thermal behaviour of polymeric Langmuir-Blodgett multilayers}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17378}, year = {1989}, abstract = {Langmuir-Blodgett multilayers of hydrocarbon and fluorocarbon polymers with hydrophilic spacer, lipid-polyelectrolyte complexes and mesogenic polymers have been prepared. The thermal behaviour of the multilayers was studied by small angle X-ray scattering, IR and UV—visible spectroscopy. Good thermal stabilities were found for the various classes of polymers. In addition, for both complexed multilayers and mesogenic polymer films, reorientation processes were observed.}, language = {en} } @article{ErbilRoggeŞenetal.2013, author = {Erbil, Fethiye and Rogge, Lisa and Şen, Nazile and Siwick, Markus}, title = {Working in a multicultural group}, series = {Potsdamer geographische Praxis}, journal = {Potsdamer geographische Praxis}, number = {3}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {2194-1599}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65973}, pages = {75 -- 81}, year = {2013}, abstract = {1. Motivation 2. Requirements 3. Positive sides of multicultural group work 4. Difficulties while Working in a Multicultural Group 5. Overall Judgement of the Project 6. Long-term Effects}, language = {en} } @phdthesis{ErbelloDoelesso2023, author = {Erbello Doelesso, Asfaw}, title = {Cenozoic magma-assisted continental rifting and crustal block rotations in an extensional overlap zone between two rift segments, Southwest Ethiopia, East Africa}, doi = {10.25932/publishup-61096}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-610968}, school = {Universit{\"a}t Potsdam}, pages = {xvii, 167}, year = {2023}, abstract = {Continental rifts are key geodynamic regions where the complex interplay of magmatism and faulting activity can be studied to understand the driving forces of extension and the formation of new divergent plate boundaries. Well-preserved rift morphology can provide a wealth of information on the growth, interaction, and linkage of normal-fault systems through time. If rift basins are preserved over longer geologic time periods, sedimentary archives generated during extensional processes may mirror tectonic and climatic influences on erosional and sedimentary processes that have varied over time. Rift basins are furthermore strategic areas for hydrocarbon and geothermal energy exploration, and they play a central role in species dispersal and evolution as well as providing or inhibiting hydrologic connectivity along basins at emerging plate boundaries. The Cenozoic East African rift system (EARS) is one of the most important continental extension zones, reflecting a range of evolutionary stages from an early rift stage with isolated basins in Malawi to an advanced stage of continental extension in southern Afar. Consequently, the EARS is an ideal natural laboratory that lends itself to the study of different stages in the breakup of a continent. The volcanically and seismically active eastern branch of the EARS is characterized by multiple, laterally offset tectonic and magmatic segments where adjacent extensional basins facilitate crustal extension either across a broad deformation zone or via major transfer faulting. The Broadly Rifted Zone (BRZ) in southern Ethiopia is an integral part of the eastern branch of the EARS; in this region, rift segments of the southern Ethiopian Rift (sMER) and northern Kenyan Rift (nKR) propagate in opposite directions in a region with one of the earliest manifestations of volcanism and extensional tectonism in East Africa. The basin margins of the Chew-Bahir Basin and the Gofa Province, characterized by a semi-arid climate and largely uniform lithology, provide ideal conditions for studying the tectonic and geomorphologic features of this complex kinematic transfer zone, but more importantly, this area is suitable for characterizing and quantifying the overlap between the propagating structures of the sMER and nKR and the resulting deformation patterns of the BRZ transfer zones. In this study, I have combined data from thermochronology, thermal modeling, morphometry, paleomagnetic analysis, geochronology, and geomorphological field observations with information from published studies to reconstruct the spatiotemporal relationship between volcanism and fault activity in the BRZ and quantify the deformation patterns of the overlapping rift segments. I present the following results: (1) new thermochronological data from the en-{\´e}chelon basin margins and footwall blocks of the rift flanks and morphometric results verified in the field to link different phases of magmatism and faulting during extension and infer geomorphological landscape features related to the current tectonic interaction between the nKR and the sMER; (2) temporally constrained paleomagnetic data from the BRZ overlap zone between the Ethiopian and Kenyan rifts to quantitatively determine block rotation between the two segments. Combining the collected data, time-temperature histories of thermal modeling results from representative samples show well-defined deformation phases between 25-20 Ma, 15-9Ma, and ~5 Ma to the present. Each deformation phase is characterized by the onset of rapid cooling (>2°C/Ma) of the crust associated with uplift or exhumation of the rift shoulder. After an initial, spatially very diffuse phase of extension, the rift has gradually evolved into a system of connected structures formed in an increasingly focused rift zone during the last 5 Ma. Regarding the morphometric analysis of the rift structures, it can be shown that normalized slope indices of the river courses, spatial arrangement of knickpoints in the river longitudinal profiles of the footwall blocks, local relief values, and the average maximum values of the slope of the river profiles indicate a gradual increase in the extension rate from north (Sawula basin: mature) to south (Chew Bahir: young). The complexity of the structural evolution of the BRZ overlap zone between nKR and sMER is further emphasized by the documentation of crustal blocks around a vertical axis. A comparison of the mean directions obtained for the Eo-Oligocene (Ds=352.6°, Is=-17.0°, N=18, α95=5.5°) and Miocene (Ds=2.9°, Is=0.9°, N=9, α95=12.4°) volcanics relative to the pole for stable South Africa and with respect to the corresponding ages of the analyzed units record a significant counterclockwise rotation of ~11.1°± 6.4° and insignificant CCW rotation of ~3.2° ± 11.5°, respectively.}, language = {en} } @phdthesis{Erbe2004, author = {Erbe, Andreas}, title = {Ellipsometrische Lichtstreuung als neue Methode zur Charakterisierung der Grenzfl{\"a}che von Kolloiden}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001565}, school = {Universit{\"a}t Potsdam}, pages = {123}, year = {2004}, abstract = {Die ellipsometrische Lichtstreuung wird als eine neue, leistungsf{\"a}hige Methode zur Charakterisierung von Schichten um kolloidale Partikel vorgestellt. Theoretische Grundlage der Methode ist die Mie-Theorie der Lichtstreuung. Experimentell wurde die Polarisationsoptik eines Null-Ellipsometers in den Strahlengang eines Lichtstreuaufbaus eingebaut. Wie in der Reflexionsellipsometrie um den Brewsterwinkel herum erh{\"a}lt man in der ellipsometrischen Streuung einen Winkelbereich, in dem die Methode empfindlich auf Schichten an der Oberfl{\"a}che der Partikel ist. An verschiedenen Systemen wurde die Tauglichkeit der ellipsometrischen Streuung zur Charakterisierung von Schichten auf Partikeln demonstriert. So wurden Dicke und Brechungsindex einer thermosensitiven Schicht von Poly(N-isopropylacrylamid) auf einem Poly(methylmethacrylat)-Kern bestimmt. Damit ist es m{\"o}glich, experimentell den Schichtbrechungsindex und damit den Quellungsgrad zu bestimmen. Des Weiteren wurde der Einfluss der NaCl-Konzentration auf die Polyelektrolyth{\"u}lle von Poly(methylmethacrylat)-Poly(styrolsulfonat)-Blockcopolymer-Partikeln untersucht. Die Polyelektrolytketten liegen im hier untersuchten Beispiel nicht gestreckt vor. Als drittes wurde die Verteilung von niedermolekularen Ionen um elektrostatisch stabilisierte Poly(styrol)-Latexpartikel in Wasser untersucht. Hier wurde gezeigt, dass die beobachteten Schichtdicken und Schichtbrechungsindizes viel gr{\"o}ßer sind, als nach der klassischen Poisson-Boltzmann-Theorie zu erwarten ist. Des Weiteren wurde die Doppelbrechung von unilamellaren Lipidvesikeln bestimmt. Außerdem wurden Messungen der dynamische Lichtstreuung im Intensit{\"a}tsminimum der Ellipsometrie durchgef{\"u}hrt. Dabei wird ein Prozess mit einer Korrelationszeit, die unabh{\"a}ngig vom Streuvektor, aber abh{\"a}ngig von der verwendeten Wellenl{\"a}nge ist, sichtbar. Die Natur dieses Prozesses konnte hier nicht vollst{\"a}ndig gekl{\"a}rt werden.}, language = {de} } @misc{EppeWeissKleinetal.1999, author = {Eppe, Ulrike and Weiß, Norman and Klein, Eckart and H{\"a}ußler, Ulf and Hofmann, Bianca}, title = {MenschenRechtsMagazin : Informationen | Meinungen | Analysen}, volume = {4}, number = {2}, issn = {1434-2820}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56653}, year = {1999}, language = {de} } @misc{EppeStuermerWeissetal.1999, author = {Eppe, Ulrike and St{\"u}rmer, Christiane and Weiß, Norman and Palermo, Francesco}, title = {MenschenRechtsMagazin : Informationen | Meinungen | Analysen}, volume = {4}, number = {1}, issn = {1434-2820}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56662}, year = {1999}, language = {de} }