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In the degradation of ammonia (NH4+) to gaseous nitrogen (N2), the nitrification is one of the two reaction steps. The nitrification itself is divided in two steps and is performed by two different types of bacteria. Current literature has shown that there are types of bacteria, which have the genetic equipment to perform both steps in one bacteria. Nevertheless, in wastewater and landfill leachate treatment, ammonia-oxidizing organisms (AOO) and nitrite-oxidizing organisms (NOO) occur as a symbiosis. The intermediate of the two consecutive reaction steps (NO2-, nitrite) is toxic. For this reason, both steps are necessary for the two bacterial groups. To determine the ratio of AOO, NOO and heterotrophic bacteria (which use organic compounds as carbon and energy source) the oxygen uptake rate (OUR) with selective inhibition with N-allylthiourea (ATU) and azide is used. In the inflow of a pilot plant in one street a step by step increased amount of a process water out of a fermentation plant was added to the landfill leachate. For comparison, the other street was supplied only with landfill leachate with the same amount of nitrogen. As a result, comparable values for the different bacterial groups and reproducible results were measured and lead to a better understanding of the analysed nitrification sludge. Deeper understanding of the behavior of the different groups will result in a reduce risk of malfunctions and a more stable operation in the wastewater or landfill leachate treatment plant.
This contribution deals with the topic of the consistent further development of a wheel hub motor for battery electric vehicles (BEV) based on the principle of an outer rotor switched reluctance machine (SRM). The research work presented in this paper was founded by the ERDF.NRW program, Investment for Growth and Employment and the European Regional Development Fund. The R&D project was named Switched - Reluctance fo(u)r wheel (SR4Wheel). Based on the experience made by first prototype Evolution 0 (EVO 0), developed in the Laboratory for Automation Engineering, Power Electronics and Electrical Drives of the Cologne University of Applied Sciences (CUAS), the test results of EVO 1, as well as the redesign, EVO 2 is presented in this paper.
The prototype EVO 0, a first proof of concept leads to several optimizations and lessons learned for the predecessor model EVO 1. The overall target of developing such a gearless outer rotor wheel hub motor is the full integration of the complete machine including its power electronics into the given space between the original friction brake and the rim. Furthermore, due to the additional integration of the power electronics, great opportunities in terms of new vehicle design as well as retrofitting capabilities of already existing vehicle platforms can be achieved. Thereby, further drive train assembly space like the engine compartment is no longer necessary. The SRM does not require magnets for torque production which leads to independence from the changeable commodity prices on the rare earth element markets. This paper presents the developing process, testing, and verification of the innovative drive train concept starting with the final CAD of EVO 1. During the testing and verification process a machine characteristic mapping is performed on a drive train test bench and subsequently the results of a finite element analysis (FEA) are plausibility checked by the test bench results. The process continues with energy conversion test scenarios of the project demonstrator vehicle on a roller test bench focused on noise vibrationharshness (NVH) behavior and efficiency. As a conclusion, the gained knowledge by evaluating two EVO 1 prototypes on the rear axle of the test vehicle, and the design for the front axle drive train EVO 2 will be presented. As a major task on the front axle, the limited space due to the large disc brake can be identified and solved.
The synthesis of 17-hydroxy-oleic acid based oligomeric esters was investigated with immobilized Pseudozyma antarctica Lipase B and hexanediol as co-substrate. The effects of different reaction parameters on velocity and product composition at equilibrium conditions were analyzed. The synthesis of oleic acid esters was used as a reference system for initial evaluation of reaction parameters. The reaction with oleic acid and hexanediol was fastest at an enzyme concentration of 5% at 60 °C and high conversions of > 90 % were achieved in non-polar solvents in the presence of molecular sieves. In heptane an oleic acid conversion of 96 % was reached with a final diester to monoester ratio of > 4:1. In syntheses trials with 17-hydroxy-oleic acid the formation of oligomers was verified with GPC, however; conversion was generally lower than with oleic acid. Removal of hydroxyl fatty acid monomers and dimers and the formation ester functionalities could be verified by GC analysis. An increase of the degree of oligomerization was observed simultaneously by GPC analysis. The number-average molecular weight was around 1400 in the best trials corresponding to a degree of oligomerization of around 4 units of hydroxyl-fatty acid attached to a hexanediol core. Though transformations were not complete, the final oligomer size was in the lower range of polyester diols used for polyurethane manufacturing.
REST became the go to approach when it comes to large scale distributed systems on, or outside the World Wide Web. This paper aims to give a brief overview of what REST is and what its main draws and benefits are. Secondly, I will showcase the implementation of REST using HTTP and why this approach became as popular as it is today. Based on my research I concluded that REST’s advantages in scalability, coupling, performance and its seamless integration with HTTP enabled it to rightfully overtake classic RPC based approaches.
Modern industrial biomass combustion plants are regulated by the power and/or combustion control. In this process, the implemented sensors collect the relevant measured data. The aim is to achieve ideal combustion with optimum efficiency and to minimize gas emissions. For this purpose, a group within the research project Metabolon developed new regulatory procedures in order to record the combustion process of a biomass combustion plant using a webcam. The recordings were evaluated automatically and were used for a better monitoring of the process. In addition, the webcam-based method aims, among other things, to provide private homes with a cost-effective variant as an alternative to industrial system solutions.
The quantification of greenhouse gas emissions from aquatic ecosystems requires knowledge about the spatial and temporal dynamics of free gas in sediments. Freezing the sediment in situ offers a promising method for obtaining gas‐bearing sediment samples, unaffected by changes in hydrostatic pressure and sample temperature during core withdrawal and subsequent analysis. This article presents a novel freeze coring technique to preserve the in situ stratigraphy and gas bubble characteristics. Nondestructive X‐ray computed tomography (CT) scans were used to identify and characterize coring disturbances of gravity and freeze cores associated with gassy sediment, as well as the effect of the freezing process on the gas bubble characteristics. Real‐time X‐ray CT scans were conducted to visualize the progression of the freezing process. Additional experiments were conducted to determine the freezing rate to assess the probability of sediment particle/bubble migration, and gas bubble nucleation at the phase transition of pore water to ice. The performance of the freeze coring technique was evaluated under field conditions in Olsberg and Urft Reservoir (Germany). The results demonstrate the capability of the freeze coring technique for the preservation of gas‐bearing sediments and the analysis of gas bubble distribution pattern in both reservoirs. Nevertheless, the obtained cores showed that nearly all gravity and freeze cores show some degree of coring disturbances.
Über Ludwig Mies van der Rohe ist alles gesagt, oder? 1886 in Aachen geboren, entwickelte er sich zu einem der renommiertesten und bekanntesten Architekten weltweit – mit ikonischen Bauten wie der Neuen Nationalgalerie in Berlin oder Bauten wie dem Seagram Building in New York. Viele Publikationen sind zu seinem Leben und seinen Arbeiten erschienen. Jedoch finden die nordrhein-westfälischen Projekte, mit Ausnahme der Krefelder Villen Lange und Esters, darin erstaunlich wenig Beachtung.
Erstaunlich deshalb, weil sich besonders an diesen Projekten sehr eindrucksvoll sein Lebensweg aufzeigen lässt – vom rheinischen Handwerkslehrling über den Bauhausdirektor bis hin zum weltweit agierenden Architekten. Innerhalb der Baukunst des 20. Jahrhunderts spiegeln seine Arbeiten im heutigen Nordrhein-Westfalen die Entwicklung vom Jugendstil zum International Style.
Der Erforschung dieser vielfältigen Spuren widmen sich mittlerweile seit vielen Jahren Studentinnen und Studenten sowie Wissenschaftlerinnen und Wissenschaftler unterschiedlicher westdeutscher Architektur-Hochschulen. Unter der Leitung der beiden Herausgeber, Prof. Dr. Daniel Lohmann und Prof. Norbert Hanenberg, dieses Architekturführers wurden die Projekte dokumentiert, Spuren gelesen, Quellen ausgewertet, und die Geschichte von „Mies im Westen“ wurde nachvollzogen.
Die vorliegende Publikation ist in Zusammenarbeit mit dem Museum für Architektur und Ingenieurkunst NRW im Rahmen der Lehrveranstaltungen der TH Köln und der TH Mittelhessen (Gießen) mit Studierenden entstanden.
Zivile unbemannte Luftfahrtsysteme in der Akutphase internationaler humanitärer Hilfseinsätze
(2019)
Diese Arbeit konstruiert Einsatzbereiche ziviler unbemannter Luftfahrtsysteme in humanitären Hilfseinsätzen unmittelbar nach einer Katastrophe. Die Auswertung der Schnittmenge der technischen Fähigkeitsanalyse mit der – unter Verwendung von Experteninterviews durchgeführten – operativen Bedarfsanalyse des humanitären Sektors stellt die Basis für die Konstruktion der neun Anwendungsbereiche dar. Abschließend werden diese vor einem technischen, rechtlichen sowie ethischen Hintergrund diskutiert und bewertet.
Durch das permanente Wachstum der Weltbevölkerung wird der Bedarf von Textilien stetig steigen. Die Produktvielfalt sowie der Konsum der Textilien werden immer größer. Die aktuellen Recyclingtechniken ermöglichen es nicht, den Rohstoffkreislauf für Textilien zu schließen. Dies liegt auch darin begründet, dass derzeit große Mengen der Textilien aus Mischgeweben zwischen Baumwolle und PET bestehen. Die Trennung dieser Komponenten ist jedoch eine Grundvoraussetzung für die Entwicklung eines geschlossenen Rohstoffkreislaufs und stellt gleichzeitig eine große Herausforderung für das Recycling dar. Durch chemische Recyclingverfahren können die Rohstoffe getrennt, aufbereitet und in die Textilproduktion zurückgeführt werden. In dieser Arbeit wird aufgezeigt, wie ein chemischer Recyclingprozess, der einen geschlossenen Rohstoffkreislauf erlaubt, technisch realisiert werden kann. Der Prozess erzeugt eine PET-Fraktion und eine Celluloselösung, die in weiteren Verarbeitungsschritten zu einer Regeneratfaser versponnen wird. In dieser frühen Projektphase werden in dieser Arbeit ebenfalls die Investitionsausgaben und die Herstellungskosten für das Verfahren abgeschätzt.
Metallic tubular micro-components play an important role in a broad range of products,
from industrial microsystem technology, such as medical engineering, electronics and optoelectronics, to sensor technology or microfluidics. The demand for such components is increasing, and forming processes can present a number of advantages for industrial manufacturing. These include, for example, a high productivity, enhanced shaping possibilities, applicability of a wide spectrum of materials and the possibility to produce parts with a high stiffness and strength. However, certain difficulties arise as a result of scaling down conventional tube forming processes to the microscale. These include not only the influence of the known size effects on material and friction behavior, but also constraints in the feasible miniaturization of forming tools. Extensive research work has been conducted over the past few years on micro-tube forming techniques, which deal with the development of novel and optimized processes, to counteract these restrictions. This paper reviews the relevant advances in micro-tube fabrication and shaping. A particular focus is enhancement in forming possibilities, accuracy and obtained component characteristics, presented in the reviewed research work. Furthermore, achievements in severe plastic deformation for micro-tube generation and in micro-tube testing methods are discussed.