464 Works

Regelungsverfahren für dieselelektrische Schiffsantriebe für hohe dynamische Anforderungen

Robert Benjamin Banek
Bei Schiffen mit dieselelektrischen Antrieben muss die Leistung der Fahrmotoren begrenzt werden, um eine Überlastung der Dieselgeneratoren zu verhindern. Als Alternative zur heute üblichen Begrenzung durch Propellerdrehzahlrampen wird eine dynamische Begrenzung entwickelt, welche das momentane Lastaufschaltvermögen der Dieselgeneratoren berücksichtigt. Das momentane Lastaufschaltvermögen wird dabei durch wenig rechenintensive Hammerstein-Modelle ermittelt. Eine solche optimierte Begrenzung der Fahrmotoren kann die dynamische Leistungsfähigkeit des dieselelektrischen Antriebs deutlich verbessern.

In situ high-energy X-ray diffraction during hot-forming of a multiphase TiAl alloy

Andreas Stark, Marcus Willi Rackel, Aristide Tchouaha Tankoua, Michael Oehring, Norbert Schell, Lars Lottermoser, Andreas Schreyer & Florian Pyczak
Intermetallic γ-TiAl based alloys exhibit excellent high-temperature strength combined with low density. This makes them ideal candidates for replacing the twice as dense Ni base super-alloys, currently used in the medium temperature range (~700 °C) of industrial and aviation gas turbines. An important step towards the serial production of TiAl parts is the development of suitable hot-forming processes. Thermo-mechanical treatments often result in mechanical anisotropy due to the formation of crystallographic textures. However, with conventional...

Scaling effects in the mechanical behaviour of carbon nanoparticle modified fibre reinforced polymers

Christian Leopold
Diese Arbeit betrachtet den Einfluss einer Nanopartikelmodifikation auf das Schadensverhalten und die resultierenden mechanischen Eigenschaften von Epoxidmatrix und Faser-Kunststoff-Verbunden (FKV). Ein Vergleich verschiedener Nanopartikel - Morphologien im Hinblick auf ihr Potential für den Einsatz in FKV wird durchgeführt. Da die Volumina zwischen den Fasern in FKV sehr klein sind, liegt der Fokus der Untersuchungen auf Größeneffekten. Der Einfluss wird anhand der Schädigungsmechanismen in Abhängigkeit von der Partikelmorphologie diskutiert. Ein bedarfsgerechter Modifizierungsansatz erlaubt die exakte Analyse...

M02.001 CHNS - elemental analysis

Helmut Diedrich & Alina Stahl
This method describes the determination of nitrogen, hydrogen, sulfur and total carbon (TC) in homogenised solid samples such as dried sludge, soil, biological waste or sediments, containing more than 1 g analyte per kg of dry matter (0.1% w/w). Therefore, samples are weighed and analysed by NCHS analyser with internal thermal conductivity detector (TCD). The additional treatment of the samples with hydrochloric acid and thus, the removal of total inorganic carbon (TIC), allows the calculation...

M02.008 Determination of dry residue in solid samples

Tanja Millfahrt & Alina Stahl
Nach ausreichender Homogenisierung einer Feststoffprobe wie z.B. Schlamm, Sedimente, Boden oder Kompost wird diese als Doppelbestimmung im Trockenschrank bei 105 ± 3°C bis zur Massekonstanz getrocknet und der Rückstand gewogen. Die Angabe des Ergebnisses erfolgt in Prozent oder in g/kg.

M03.001 Gravimetric determination of low volatile lipophilic substances

Alina Stahl & Heike Frerichs
For the gravimetric determination of low volatile lipophilic substances, which can be suspended, emulsified or dissolved in water, samples are extracted with petroleum benzine. By means of a micro separator the upper organic layer is separated and traces of water are removed with sodium sulfate as drying agent. After evaporation, the amount of low volatile lipophilic substances is determined by weighing. Results are reported in mg/l.

Part load behaviour of power plants with a retrofitted post-combustion CO₂ capture process

Volker Roeder & Alfons Kather
The flexible and part load operation of fossil-fuelled power plants will increase due to the higher share of fluctuating renewable energies, like wind and solar power. In this work the part load behaviour of the post-combustion CO₂ capture (PCC) process is evaluated. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.6% at full load to 41.5% at 40% load. The net efficiency with PCC using 7 m MEA (monoethanolamine) as solvent decreases...

Rigorose Fehlerschranken für das Elektronenstrukturproblem

Kai Torben Ohlhus
Die vorliegende Doktorarbeit behandelt die Berechnung rigoroser Fehlerschranken für konische Optimierungsprobleme, einer Spezialform der konvexen Optimierung. Der Anwendungsschwerpunkt ist die Berechnung der Elektronenstruktur, insbesondere deren Grundzustandsenergie. Dies ist bis heute eine schwierig lösbare Problemstellung der Quantenchemie und kann als konisches Optimierungsproblem relaxiert werden. Es werden rigorose untere Fehlerschranken für das Elektronenstrukturproblem hergeleitet, welche alle Rundungsfehler miteinbeziehen und mit vernachlässigbarem Speicher- und Zeitaufwand für eine Vielzahl von Molekülen berechnet werden.

Lean management: Mitarbeiterbefähigung zur dezentralen Prozessverbesserung

Matthias Ehni
Der globale Wettbewerb und die Dynamik der Nachfrage erfordern von Unternehmen eine hochfrequente sowie kontinuierliche Entwicklung der Leistungsprozesse. Die vorliegende Arbeit unterstützt Unternehmen bei der Beherrschung dieser Aufgabe, indem ein Vorgehensmodell bereitstellt wird, das die Mitarbeiter dezentraler Bereiche befähigt, ihre Prozesse zielführend auf Basis von Lean Management zu optimieren.

First Glycoside Hydrolase Family 2 Enzymes from Thermus antranikianii and Thermus brockianus with β-Glucosidase Activity

Carola Schröder, Saskia Blank & Garabed Antranikian
Two glycoside hydrolase encoding genes (tagh2 and tbgh2) were identified from different Thermus species using functional screening. Based on amino acid similarities, the enzymes were predicted to belong to glycoside hydrolase (GH) family 2. Surprisingly, both enzymes (TaGH2 and TbGH2) showed twofold higher activities for the hydrolysis of nitrophenol-linked β-D-glucopyranoside than of -galactopyranoside. Specific activities of 3,966 U/mg for TaGH2 and 660 U/mg for TbGH2 were observed. In accordance, K m values for both enzymes...

Reversibility of asymmetric catalyzed C-C bond formation by benzoylformate decarboxylase

Marco Berheide, Selin Kara & Andreas Liese
Benzoylformate decarboxylase (BFD) from Pseudomonas putida catalyzed the formation of 2-hydroxy-1-phenylpropanone (2-HPP), a 2-hydroxy ketone, from the kinetic resolution of rac-benzoin in the presence of acetaldehyde. The formation rate of 2-HPP via kinetic resolution of benzoin was 700-fold lower compared to the formation via direct carboligation of benzaldehyde and acetaldehyde. Further investigations revealed that BFD not only accepts (R)-benzoin but also 2-HPP as the substrate. A typical Michaelis–Menten type kinetics was observed starting from enantiopure...

The electro-chemo-mechanical coupling in lithium alloy electrodes and its origins

Tobias Kitzler, Emad Maawad, Daniel M. Többens, Markus Ziehmer & Jürgen Markmann
A method to identify and separate the influence of changes in the surface stress from the bulk stress in a model lithium-ion battery electrode during electrochemical cycling was developed. The strategy for this separation is based on the different influence of surface and bulk stresses on the coupling between electrode potential and mechanical strain as measured by dynamic electro-chemo-mechanical analysis and the coupling between the transferred electric charge and the elastic strain as determined by...

Rebitagem por fricção (“FricRiveting”) de liga de alumínio 6056 T6 e poliamida 6: influência da velocidade de rotação na formação da zona de ancoragem e no desempenho mecânico

Bruno Cordeiro de Proença, Lucian A. Blaga, Jorge F. dos Santos, Leonardo Bresciani Canto & Sergio Amancio
Hybrid metal-polymer structures are an alternative solution to reduce weight and fuel consumption in the transportation industry in order to minimize the emission of noxious gases in regard to the greenhouse effect. Friction Riveting is a relatively new technique for joining metal-polymer hybrid structures. The process relies on the generation of frictional heat between the components causing the plastic deformation of the metallic rivet and its anchoring in the polymer component. This study evaluated the...

Literatur- und Onlinequellen der Lean Construction Studie

Jan Onne Backhaus
Das Literaturverzeichnis der Lean Construction Studie

Real time pose control of an industrial robotic system for machining of large scale components in aerospace industry using laser tracker system

Christian Moeller, Hans Christian Schmidt, Philip Koch, Christian Boehlmann, Simon Kothe, Jörg Wollnack & Wolfgang Hintze
Copyright © 2017 SAE International. The high demand of efficient large scale machining operations by concurrently decreasing operating time and costs has led to an increasing usage of industrial robots in contrast to large scaled machining centers. The main disadvantage of industrial robots used for machining processes is their poor absolute accuracy, caused by the serial construction, resilience of gearings and sensitivity for temperature changes. Additionally high process forces that occur during machining of CFRP...

Isolation and biochemical characterization of a glucose dehydrogenase from a hay infusion metagenome

Alexander Basner & Garabed Antranikian
Glucose hydrolyzing enzymes are essential to determine blood glucose level. A high-throughput screening approach was established to identify NAD(P)-dependent glucose dehydrogenases for the application in test stripes and the respective blood glucose meters. In the current report a glucose hydrolyzing enzyme, derived from a metagenomic library by expressing recombinant DNA fragments isolated from hay infusion, was characterized. The recombinant clone showing activity on glucose as substrate exhibited an open reading frame of 987 bp encoding...

The dynamic behaviour of a non-stationary elevator compensating rope system under harmonic and stochastic excitations

Stefan Kaczmarczyk, Radoslaw Marek Iwankiewicz & Yoshiaki Terumichi
Moving slender elastic elements such as ropes, cables and belts are pivotal components of vertical transportation systems such as traction elevators. Their lengths vary within the host building structure during the elevator operation which results in the change of the mass and stiffness characteristics of the system. The structure of modern high-rise buildings is flexible and when subjected to loads due to strong winds and earthquakes it vibrates at low frequencies. The inertial load induced...

Development of a synthetic synovial fluid for tribological testing

Emely Lea Bortel, Baptiste Charbonnier & Roman Heuberger
Wear tests of joint prostheses are usually performed using bovine calf serum. The results from different laboratories are hardly ever comparable as, for example, the protein concentration and the protein composition of the serum-based test liquids vary. In addition, the viscosity of these test liquids is similar to that of water and does not match the more viscous synovial fluid. The present work was aimed at developing a synthetic synovial fluid as an alternative to...

Social Influence, status, and entrepreneurial entry: evidence from the comic book industry

Michael Engel
Diese Dissertation untersucht wie sich die Struktur sozialer Netzwerke auf den unternehmerischen Eintritt auswirkt. Sie analysiert die Effekte von sozialem Einfluss und Status auf die Entscheidung von Personen, ein neues, selbst erstelltes Angebot auf den Markt zu bringen. Bisherige Arbeiten haben diese Effekte zwar nachgewiesen, konnten die zugrundeliegenden Mechanismen aber noch nicht aufdecken. Ausgehend von der Netzwerktheorie leiten wir Hypothesen zu proximitätsbasierten Ansteckungs- und statusbasierten Konvergenzmechanismen ab und testen sie im Kontext der Comic-Industrie mit...

An example of visually supported design of modular product families

Nicolas Gebhardt, Tammo Bahns & Dieter Krause
© 2014 Published by Elsevier B.V. To offer individualized products at globally marketable prices, the Integrated PKT-Approach for Developing Modular Product Families aims to generate high external product variety based on a low internal process and component variety. Specific visualizations are an important factor in the success of this approach. In this paper the Module Interface Graph (MIG) developed at the Institute for Product Development and Mechanical Engineering Design (PKT) is used to show how...

Digital transformation in maritime and city logistics : smart solutions for logistics

This volume contains research contributions by an international group of authors addressing innovative and technology-based approaches for logistics and sustainability. They present simulation studies, systems and models for optimizations and digitalized solutions with a focus on maritime as well port and city logistics. This volume, edited by Carlos Jahn, Wolfgang Kersten, and Christian Ringle, provides valuable insights into digital transformation in logistics with regard to: Maritime and Port Logistics, City Logistics, Sustainability and Business Analytics.

Breaking through the bottlenecks using artificial intelligence

Julia Feldt, Henning Kontny & Axel Wagenitz
Purpose: Performance of Supply Chain is highly dependent on weak spots, so-called bottlenecks. This research paper presents the findings from the analysis of operation processes of a mid-sized producing company and the digital solution for opening up the bottlenecks in order to achieve effectiveness by cutting down the order lead time. Methodology: The study is employing several rounds of simulation based on processes and data from a manufacturing company. Findings: Simulation results demonstrate that by...

Sharing information across company borders in industry 4.0

Kai-Ingo Voigt, Julian Müller, Johannes Veile & Marie-Christin Schmidt
Purpose: Industry 4.0's potentials can only unfold exhaustively if information is shared across company boarders and along supply chains. Exchanging information, however, implies several challenges for companies. This holds especially true if it is transmitted automatically and digitally, as promoted by the concept of Industry 4.0. In response to these challenges, this paper analyzes how information sharing changes in Industry 4.0 contexts. Methodology: Expert interviews with 17 representatives from supply chain management departments of German...

Machine learning in demand planning : cross-industry overview

Nikolas Ulrich Moroff & Saskia Sardesai
Purpose: This paper aims to give an overview about the current state of research in the field of machine learning methods in demand planning. A cross-industry analysis for current machine learning approaches within the field of demand planning provides a decision-making support for the manufacturing industry. Methodology: Based on a literature research, the applied machine learning methods in the field of demand planning are identified. The literature research focuses on machine learning applications across industries...

Automatic identification system (AIS) data based ship-supply forecasting

Sandra Lechtenberg, Diego de Siqueira Braga & Bernd Hellingrath
Purpose: The bulk cargo shipping industry is characterized by high cost pressure. Chartering vessels at low prices is important to increase the margin of transporting cargo. This paper proposes a three-step, AI-based methodology to support this by forecasting the number of available ships in a region at a certain time. Methodology: Resulting from discussions with experts, this work proposes a threestep process to forecast ship numbers. It implements, compares and evaluates different AI approaches for...

Registration Year

  • 2019

Resource Types

  • Text