57 Works

Self-stabilizing algorithms in wireless sensor networks

Gerry Siegemund
The presented dissertation focuses on the applicability of self-stabilizing algorithms in systems using wireless communication. Especially wireless sensor networks (WSN) which use low power radios that are prone to message loss and corruption. Furthermore, temporary node failures (e.g., due to exhausted batteries) are common sources of nonconformances. Thus, distributed algorithms, middleware systems, and applications have to respond to these faults. A typical approach is to foresee such error situations and program routines to react to...

Bibliothek in Zukunft?! Texte von Studierenden zum Wandel von Bibliotheken : aus dem Bachelor-Seminar „Wissenschaftliches Arbeiten“ an der TU Hamburg

Thomas Hapke
Die in diesem Werk vorgestellten Texte von Studierenden zum Wandel von Bibliotheken, insbesondere von Universitätsbibliotheken, sind Ergebnisse einer Hausaufgabe, die während des Bachelor-Seminars „Wissenschaftliches Arbeiten“ erarbeitet wurden. Das Seminar wird federführend von der Universitätsbibliothek der Technischen Universität Hamburg (tub.) organisiert und ist Teil des Komplementärstudiums (Nichttechnisches Angebot NTA) der TUHH.

Fretting-Korrosion modularer Hüftendoprothesen

Dennis Bünte
Early failure of total hip replacements can be caused by the release of wear products from modular junctions due to fretting-corrosion. The aim was to identify design factors that make the analyzed tapers susceptible to wear and corrosion. A quantitative analysis of wear from circular and flat taper designs for a mixed metal coupling (CoCr-TMZF) was performed. Based on the reconstruction of explanted taper geometries, individual engagement properties are determined, providing an estimate of the...

Jahresbericht 2016 des Präsidiums der Technischen Universität Hamburg

Technische Universität Hamburg & Garabed Antranikian
Annual report by the president of the TUHH 2016

A conceptual modeling approach to health-related urban well-being

Malte Von Szombathely, Myriam Albrecht, Dejan Antanaskovic, Jobst Augustin, Matthias Augustin, Benjamin Bechtel, Thomas Bürk, Jana Fischereit, David Grawe, Peter Hoffmann, Giedrius Kaveckis, Anne Caroline Krefis, Jürgen Oßenbrügge, Jürgen Scheffran & Katharina Heinke Schlünzen
In cities, social well-being faces obstacles posed by globalization, demographic and climate change, new forms of social organization, and the fragmentation of lifestyles. These changes affect the vulnerability of city societies and impact their health-related urban well-being (UrbWellth). The conceptual model introduced in this paper systematizes the relevant variables while considering previous research, and establishes the target value UrbWellth. The model differs from existing approaches mainly in the analytical distinctions it suggests. These allow us...

Use of novel composite coagulants for arsenic removal from waters : experimental insight for the application of polyferric sulfate (PFS)

Ioannis A. Katsoyiannis, Nikolaos M. Tzollas, Athanasia K. Tolkou, Manassis Mitrakas, Mathias Ernst & Anastasios I. Zouboulis
In the present study, several pre-polymerized coagulants of iron and aluminum were tested for their efficiency towards As(V) and As(III) removal from water sources. The results showed that the pre-polymerized coagulants of iron, such as poly-ferric sulfate and poly-ferric silicate chloride, were very efficient for As(V) removal. With regard to As(III) removal, among all examined coagulants, including the conventional ferric chloride, only the poly-ferric sulfate (PFS) was able to reduce As(III) to concentrations below the...

Impact of powdered activated carbon structural properties on removal of organic foulants in combined adsorption-ultrafiltration

Martin Schulz, Sönke Bünting & Mathias Ernst
The impact of structural properties of three commercial PACs as well as two mechanically ground PACs on their efficiency in NOM removal and fouling reduction in combined adsorption-ultrafiltration (PAC-UF) of northern German groundwater was investigated. All PACs showed highest adsorption affinity for medium molecular weight NOM fractions. The meso-pore surface area rather than the total surface area (B.E.T.) mainly governed the extent of NOM removal. However, adsorption of macromolecular NOM fractions, which were found to...

Using an interactive lattice Boltzmann solver in fluid mechanics instruction

Mirjam Sophia Glessmer & Christian F. Janßen
This article gives an overview of the diverse range of teaching applications that can be realized using an interactive lattice Boltzmann simulation tool in fluid mechanics instruction and outreach. In an inquiry-based learning framework, examples are given of learning scenarios that address instruction on scientific results, scientific methods or the scientific process at varying levels of student activity, from consuming to applying to researching. Interactive live demonstrations on portable hardware enable new and innovative teaching...

Online monitoring of surface cracks and delaminations in carbon fiber/epoxy composites using silver nanoparticle based ink

Till Augustin, Danny Grunert, Hauke H. Langner, Vico Haverkamp & Bodo Fiedler
In this study, we present an online-monitoring approach using silver nanoparticle based ink on carbon fiber reinforced plastics (CFRP). After production of CFRP plates in a prepreg autoclave process and printing conductive paths on the material, we investigate the conductive paths of printed silver nanoparticle-based ink on CFRP by light microscopy. Mechanical tests with simultaneous electrical resistance measurements demonstrate the possibility to detect particular modes of failure with samples specifically designed to promote inter-fiber failures...

Extension of the contour integral method for stochastic modeling of waveguiding structures

Jan Preibisch
Elektromagnetische Felder innerhalb von Leiterplatten, substratintegrierten Wellenleitern, sowie orthogonal gestreute Felder unendlich ausgedehnter Strukturen breiten sich in Ebenen aus. In dieser Arbeit wird die Kontourintergralmethode (CIM) erweitert, um Leiterplatten und planare Hochfrequenzbauelemente, sowie optische Bauelementen in TE und TM Polarisation zu simulieren. Das Einkoppeln in die planaren Strukturen wird mittels physikalisch motivierter Ersatzschaltungsmodelle modelliert. Zur Handhabung stochastischer Formulierungen dieser Modelle wurde die polynomielle Chaos Zerlegung (PCE) verwendet. Algorithmen und Methoden zur schnellen und aussagekräftigen Analyse...

Complete genome sequence of Thermus brockianus GE-1 reveals key enzymes of xylan/xylose metabolism

Christian Schäfers, Saskia Blank, Sigrid Wiebusch, Skander Elleuche & Garabed Antranikian
Thermus brockianus strain GE-1 is a thermophilic, Gram-negative, rod-shaped and non-motile bacterium that was isolated from the Geysir geothermal area, Iceland. Like other thermophiles, Thermus species are often used as model organisms to understand the mechanism of action of extremozymes, especially focusing on their heat-activity and thermostability. Genome-specific features of T. brockianus GE-1 and their properties further help to explain processes of the adaption of extremophiles at elevated temperatures. Here we analyze the first whole...

A concept for multi-criteria environmental assessment of aircraft trajectories

Sigrun Matthes, Volker Grewe, Katrin Dahlmann, Christine Frömming, Emma Irvine, Ling Lim, Florian Linke, Benjamin Lührs, Bethan Owen, Keith Shine, Stavros Stromatas, Hiroshi Yamashita & Feijia Yin
Comprehensive assessment of the environmental aspects of flight movements is of increasing interest to the aviation sector as a potential input for developing sustainable aviation strategies that consider climate impact, air quality and noise issues simultaneously. However, comprehensive assessments of all three environmental aspects do not yet exist and are in particular not yet operational practice in flight planning. The purpose of this study is to present a methodology which allows to establish a multi-criteria...

Laser beam welding of high-alloyed aluminium-zinc alloys

Josephin Enz
The automotive industry is currently facing major challenges. In the course of the enacting of comprehensive environmental regulations for the fuel consumption and CO2 emission of passenger vehicles in Europe and the world, the weight of future vehicles need to be considerably reduced. A weight reduction for automotive structures can be achieved by the substitution of heavy materials by lighter and stronger materials, the implementation of new designs and manufacturing technologies or ideally by a...

Metabolic and proteomic analyses of product selectivity and redox regulation in Clostridium pasteurianum grown on glycerol under varied iron availability

Christin Groeger, Wei Wang, Wael Sabra, Tyll Utesch & An-Ping Zeng
Background: Clostridium pasteurianum as an emerging new microbial cell factory can produce both n-butanol (BuOH) and 1,3-propanediol (1,3-PDO), and the pattern of product formation changes significantly with the composition of the culture medium. Among others iron content in the medium was shown to strongly affect the products selectivity. However, the mechanism behind this metabolic regulation is still unclear. For a better understanding of such metabolic regulation and for process optimization, we carried out fermentation experiments...

Innovation pathways and trajectories in India’s auto component industry

Rajnish Tiwari & Katharina Kalogerakis
India’s automotive sector has grown tremendously in the post-liberalization period. The growing domestic market, increased export opportunities and greater emphasis of vehicle manufacturers on high-quality, innovative solutions have created a context for component suppliers to ramp up their innovation capabilities as well. For about past 20 years the auto component industry has consistently acted as a key enabler of various frugal vehicles launched in India. Our multi-level and multi-approach study, making use of firm and...

Kapazitätsplanung und -steuerung in der Instandhaltungsproduktion von Investitionsgütern

Nico Koppold
With the proposed applications, uncertainty of work order times can be taken into account for capacity planning, coordination and control to reduce or avoid the consequences of uncertainty. The method adds ranges to work load planning and defines the occurrence pro-bability for this range of work load. This enables capacity flexibility to be adjusted to existing uncertainties to save costs and avoid a deficit in flexibility. Real work orders of maintenance and repair production for...

Computability Theory

Karl-Heinz Zimmermann
This book is a development of class notes for a two-hour lecture including a two-hour lab held for second-year Bachelor students of Computer Science at the Hamburg University of Technology during the last few years. The course aims to present the basic results of computability theory, including well-known mathematical models of computability such as the Turing machine, the unlimited register machine (URM), and GOTO and LOOP programs, the principal classes of computational functions like the...

Electrochemical tuning of the optical properties of nanoporous gold

Dirk Jalas, Li-Hua Shao, Rashmi Canchi, Toshiya Okuma, Slawa Lang, Alexander Petrov, Jörg Weißmüller & Manfred Eich
Using optical in-situ measurements in an electrochemical environment, we study the electrochemical tuning of the transmission spectrum of films from the nanoporous gold (NPG) based optical metamaterial, including the effect of the ligament size. The long wavelength part of the transmission spectrum around 800 nm can be reversibly tuned via the applied electrode potential. The NPG behaves as diluted metal with its transition from dielectric to metallic response shifted to longer wavelengths. We find that the...

Ultra-hoch gefüllte und orientierte CNT- und 3D-vernetzte Aerographit Epoxidkomposite: Synthese, Herstellung und Eigenschaften

Matthias Mecklenburg
In this work two different polymer nanocomposites (PNCs) with graphitic fillers in epoxy matrix are characterized. Both PNCs possess structural features, which are used to address open scientific questions in the field of carbon nanotube (CNT) based PNCs. The PNCs of this work use in-house synthesized nanoparticles, which are: mm-long, unidirectional aligned carbon nanotubes (CNTs) and covalently 3D interconnected graphite-based networks ('Aerographite', AG). For CNT-based PNCs (CNT-PNCs) a manufacturing method is introduced (patented), which allows...

End user reporting of suspicious E-mails using X-ARF

Adrian Metzner
End user e-mail abuse reporting rates are very low, however a survey conducted in this thesis revealed that the desire to report abusive e-mails exists. The reason why the report rates are so low is that the process to report abusive e-mails is very time consuming and complex. Therefore, a new process for e-mail abuse reporting is defined. In this new reporting process, end users are able to report suspicious e-mails instead of spam or...

Fluid-Struktur-Wechselwirkung in der Energie-Finite-Elemente-Methode

Marius Karger
The energy finite element method EFEM is used for modelling of high frequency dynamic behaviour of vibro-acoustic structures. The focus in this dissertation is to extend the applicability of the EFEM to more complex models including fluid-structure-interaction. Therefor the EFEM has been analyzed numerically and validated to complex structure used in the ship industry. These has been done for light and heavy fluids to analyze the effects onto the structure.

Technische Bildung im Spannungsfeld zwischen beruflicher und akademischer Bildung : die Vielfalt der Wege zu technischer Bildung ; Referate der 11. Ingenieurpädagogischen Regionaltagung 2016 an der Technischen Universität Hamburg vom 23.–25. Juni 2016

Gudrun Kammasch, Henning Klaffke & Sönke Knutzen
Im Mittelpunkt der Tagung stand der Umgang mit den besonderen aktuellen Herausforderungen in den Ingenieurwissenschaften. Der Tagungsband umfasst, neben dem Thema Durchlässigkeit zwischen beruflicher und akademischer Bildung, auch Beiträge z. B. zu Wissensstrukturen, zu Innovationen in der Ingenieurdidaktik, zu ethischen Aspekten in der Ingenieurwissenschaften und zu digitalen Medien in der Lehre. Gemeinsam beleuchten diese Beiträge die Vielfalt der Wege zu technischer Bildung .

Optimized crenellation designs for fatigue life improvement of metallic airframe structures

Jin Lu
Fatigue of airframe structures is a critical concern for the safety of aircraft. Serious accidents due to the accumulation of fatigue damages in airframes are by no means rare cases in history. Nowadays to ensure the structural integrity of the aircraft periodic inspections are performed on the airframe structure to detect and repair fatigue cracks timely. The prescribed inspection frequency is determined by the speed of fatigue crack growth from an initial detectable length to...

The Blue Engineer : Ingenieurinnen und Ingenieure mit ökologischer und sozialer Verantwortung. Ausgabe 01, Sommersemester 2017

Blue Engineering AG TUHH
The Blue Engineer hat sich der Aufgabe widmet, über inner- und außeruniversitäre Themen mit Bezug zu ganzheitlich verstandener Nachhaltigkeit zu berichten.

Numerical modelling and simulation of cavitating marine propeller flows

Maria Gaschler
A three-dimensional inviscid boundary element method for the simulation of steady and unsteady partial sheet cavitation on marine propellers is developed. The numerical method is validated in several test cases and applied to the calculation of hydrodynamic loads generated by the flow field around and behind a cavitating propeller on the surrounding structures in the port area.

Resource Types

  • Text

Publication Year

  • 2017