54 Works

Intersectionality as multi-level analysis: Dealing with social inequality

Gabriele Winker & Nina Degele
The concept of intersectionality is on its way to becoming a new paradigm in gender studies. In its current version, it denominates reciprocities between gender, race and class. However, it also allows for the integration of other socially defined categories, such as sexuality, nationality or age. On the other hand, it is widely left unclear as to which level these reciprocal effects apply: the level of social structures, the level of constructions of identity or...

Probabilistic approach to large amplitude ship rolling in random seas

Leo Dostal & Edwin Kreuzer
For a vessel in open seas, the sudden indirect excitation of roll motions due to waves from the front or rear leads to dangerous situations, sometimes even capsizing. We derive a general non-linear model, which is appropriate for the analysis of parametric excited roll motions in head or following random seas. The irregular waves are modelled in terms of a continuous time autoregressive moving average process. The resulting model of stochastic differential equations is investigated...

A knowledge-based approach for design and modelling of high lift actuation systems

M. Pfennig & F. Thielecke
High lift actuation system design is a highly iterative process. Especially the preliminary design phase, which sets the course for the following design steps, is characterized by uncertain and changing data input. Despite the importance of this early design phase, a specialized and integrated computational support is not available. The objective of the research project WissBaSys is to offer knowledge-based design assistance focused on the preliminary design of high lift actuation systems. Moreover, information concerning...

A statistical study of scattering in periodic and random helix layers

Christian Meiners & Arne F. Jacob
This paper aims at providing information on scattering in layers composed of periodic and non-periodic arrangements of small metal helices. Metal helices exhibit a pronounced resonance and are thus very effective scatterers.

Adsorption and diffusion in zeolites : the pitfall of isotypic crystal structures

Nils E. R. Zimmermann, Maciej Haranczyk, Manju Sharma, Bei Liu, Berend Smit & Frerich Keil
Untersucht wird der Einfluss von isotypischen Kristallstrukturen auf die Adsorption und Diffusion von Methan in Vollsilikatzeolithe der Gittertypen LTA, SAS und ITE. Resultate, die auf Grundlage von experimentellen Strukturen erzielt wurden, werden mit Resultaten basierend auf Strukturvorhersagen und gängigen Strukturannäherungen verglichen. Die Ergebnisse weisen darauf hin, dass der Diffusionskoeffizient hierbei sehr viel stärker beeinflusst wird als der Henry-Koeffizient. Tatsächlich können Unterschiede im Diffusionskoeffizienten von mehreren Größenordnungen beobachtet werden. Eine systematische Untersuchung hebt letztendlich hervor, dass...

Diffuser and nozzle design optimization by entropy generation minimization

Bastian Schmandt & Heinz Herwig
Diffusers and nozzles within a flow system are optimized with respect to their wall shapes for a given change in cross sections. The optimization target is a low value of the head loss coefficient K, which can be linked to the overall entropy generation due to the conduit component. First, a polynomial shape of the wall with two degrees of freedom is assumed. As a second approach six equally spaced diameters in a diffuser are...

Building on experience : learning from the past to plan for the future

Inken Feldsien-Sudhaus
Über 130 TeilnehmerInnen am Seminar der LIBER Architecture Group tauschten sich Anfang April 2008 in Budapest und Debrecen in Ungarn zu aktuellen Themen des Bibliotheksbaus aus. Ökologie und Architektur, die Sanierung und Anpassung vorhandener Gebäude an aktuelle Standards sowie das Thema Licht standen ebenso im Mittelpunkt wie Projektpräsentationen. Besichtigungen von ungarischen Bibliotheken rundeten das Tagungsprogramm ab. VertreterInnen vieler europäischer Länder waren bei dieser Tagung vertreten und trugen so zum internationalen Austausch bei. Die Tagung wurde...

Design for X - Beiträge zum 22. DfX-Symposium Oktober 2011

Dieter Krause, Kristin Paetzold & Sandro Wartzack
Das Symposium DfX soll in erster Linie jungen Wissenschaftlern die Möglichkeit geben, ihre Ideen vorzustellen und zu diskutieren. Wir freuen uns, dass nach erfolgreicher Übergabe des Staffelstabes im vergangenen Jahr von Prof. Harald Meerkamm an uns, Dieter Krause, Sandro Wartzack und mich, das Symposium nicht an Beliebtheit und Bedeutung verloren hat. Mit Bedauern mussten wir auch in diesem Jahr Beiträge aufgrund der beschränkten Kapazität ablehnen. In diesem Jahr liegt ein Schwerpunkt auf der Prozessunterstützung in...

Decentralized authorization for inter-domain collaborations with iRBAC framework

Hannah Kyungsun Baker
Inter-domain collaborations are composed of a series of tasks, whose run-time environment stretches over heterogeneous systems governed by different sets of policies. Though the collaborators are willing to allow access to their services and resources from outside of their administrative domains in order to reach the common goals of collaborations, they still desire to retain control over deciding under which conditions their resources should be available and which internal information to disclose to their collaborators....

Self-Stabilizing MAC protocols for large-scale, heavy loaded sensor networks under consideration of hidden nodes

Stefan Unterschütz & Volker Turau
In large-scale, heavy loaded sensor networks the hidden node problem significantly restricts the attainable throughput. This paper examines this issue and depicts why most TDMA as well as dedicated hybrid MAC protocols are still negatively affected by this phenomenon. The concept of probabilistic self-stabilization is adopted to provide a framework for implementable reservation MAC protocols that avoid packet loss caused by signal interferences even under high load. These protocols base upon two main primitives: continuity...

Hydrogen sorption properties of the composite system 2NaBH4+MgH2

Claudio Pistidda
The hydrogen storage properties of the system 2NaBH4+MgH2 are investigated as a model system for the class of Reactive Hydride Composites based on MgB2. The hydrogen absorption and desorption mechanisms are thoroughly elucidated. The effect of the applied hydrogen pressure and temperature on the hydrogen absorption mechanism is studied. For a given set of hydrogen pressure and temperature the dependence of the absorption reaction mechanism on the ratio of the starting reactants is also investigated....

Shear design of straight and haunched concrete beams without stirrups

Vu Hong Nghiep
Trotz langjähriger Forschungsaktivitäten, die ersten Versuche führte Mörsch 1920 durch, ist die Querkraftbemessung von Stahlbetonbalken ohne Querkraftbewehrung bislang unzurei-chend geklärt. Dies zeigt sich unter anderem darin, dass die meisten Bemessungsverfahren nicht auf einem mechanischen Modell sondern auf empirisch entwickelten Gleichungen ba-sieren, welche sehr große Streuungen und damit sehr hohe Sicherheitsfaktoren aufweisen. Das Problem der Querkraftbemessung besteht vor allem bei Platten. So weisen zahlreiche Massivbrücken in Deutschland nach der seit dem Jahre 2001 gültigen Norm rechnerisch...

Deposition of advanced phosphor coatings by flame spray pyrolysis

Roman Kubrin
Flame aerosol deposition (FAD) combines synthesis of phosphor particles by flame spray pyrolysis and their deposition onto a substrate in a single process step. Y2O3:Eu phosphor coatings consisting of sub-micrometer particles could be deposited by FAD based on droplet-to-particle conversion within minutes and had brightness equal to that of a conventional micrometer-sized phosphor. Screens of Y2O3:Eu nanophosphor produced by chemical vapor condensation FAD had lower brightness but they potentially could facilitate the highest possible (diffraction-limited)...

Urban transport and environmental justice - status quo in the USA and implications for Germany

Philine Gaffron
This report looks at the status quo of policies, legislation and discourse relating to urban road transport and environmental justice in the US. It presents the findings from literature study and a series of interviews conducted during a trip to the US in the summer of 2011. Interview partners came from research, regional and national non-governmental organizations (NGOs) and from various levels of administration. Interviews were conducted in Los Angeles, the Bay Area, Sacramento and...

Bank erosion in alluvial rivers with non-cohesive soil in unsteady flow

Mohammad Hassan Nasermoaddeli
So far the theory of bank failure in non-cohesive soils is limited to the avalanche of loose, not compacted, fully saturated discrete grains, applicable mainly to gravel banks. However, the present field investigation indicated that undercutting of the riverbank, slip failure of the submerged zone of the bank, as well as cantilever failure of the overhang are the dominant processes in non-cohesive dense (sandy) soils under unsteady flow conditions. These processes have been modelled in...

Aspects of systems for separate urine collection and treatment - selected techniques and potential implementation in an urban context

Felix Tettenborn
Um das Potential einer getrennten Erfassung und Behandlung von Urin in einem städtischen Kontext zu untersuchen, wurden Mengen und Nährstoffkonzentrationen von Substrat aus öffentlichen Urinalen gemessen. Eine Nährstoffrückgewinnung und eine Reduktion von Mikroschadstoffen in Form von Arzneimittelrückständen wurden u.a. mittels Rektifikation und Eindampfung im Pilotmaßstab realisiert. Transport und Aufwand wurden in Abhängigkeit der Größenordnung des Gesamtsystems diskutiert.

Numerical homogenization strategies for cellular materials with applications in structural mechanics

Hans-Georg Sehlhorst
In this thesis numerical homogenization strategies are developed which allow for capturing the complex behavior of cellular materials whereby the spatial discretization is based on higher-order finite element methods. In the examples anisotropy and size effects within two-dimensional foam-like structures are investigated and verified. In three dimensions CT-scans of real-world foams are transformed into numerical models which are successfully verified and validated, whereby a major focus lies on sandwich plates.

Eine Methode zur Entwicklung modularer Produktfamilien

Christoph Blees
Im Rahmen der Arbeit wird eine Methode vorgestellt, die eine durchgehende Unterstützung bei der Entwicklung modularer Produktfamilien bietet. Unter Anwendung der Methode entwickelte Produktfamilien sollen nicht nur eine einfache Konfiguration von Produktvarianten erlauben, sondern auch den vielfältigen Anforderungen aus allen Produktlebensphasen gerecht werden. Dazu werden zuerst unabhängig Produktstrukturen aus Sicht der unterschiedlichen Produktlebensphasen entwickelt. Im Anschluss werden die Produktstrukturen in einem Prozess über das Produktleben zusammengefasst.

Analysis of residual stress and fatigue crack propagation behaviour in laser welded aerospace Aluminium T-joints

Funda Seniz Bayraktar
Residual stress distribution of different configurations of laser beam welded (LBW) “skin-clip” T-joints of aerospace Aluminium alloys were determined by analyses using commercial FE code SYSWELD and by measurements using neutron diffraction technique. Fatigue crack propagation of notched middle tension panels with single central clip under constant amplitude cyclic loading and crack path development were carefully monitored to capture any possible effect of the welding process, residual stress state and local geometry of the weld...

Temperature-dependent synchrotron powder diffraction phase studies of (K0.37Na0.52Li0.03)(Nb0.87Ta0.1Sb0.03)O3 ferroelectric ceramics

Henry Ekene Mgbemere, Rodrigo P. Fernando, Manuel Hinterstein & Gerold A. Schneider
Temperature-dependent synchrotron powder diffraction measurements have been performed on leadfree ferroelectric (K0.37Na0.52Li0.03)(Nb0.87Ta0.1Sb0.03)O3 ceramics. The measurement was performed from 20 °C to 400 °C with 20 °C steps. The diffraction patterns showed the existence of two phases from 20 °C to 180 °C while the ferroelectric to paraelectric phase transition occurred between 340 °C and 360 °C. Rietveld refinement using the Fullprof software was employed and the two-phase region was refined using a combination of the...

Electrical and structural characterization of (KxNa1-x)NbO3 ceramics modified with Li and Ta

Henry Ekene Mgbemere, Jan Manuel Hinterstein & Gerold A. Schneider
(KxNa1-x)NbO3 ceramics modified with Li+ and Ta5+ have been produced using the mixed-oxide synthesis method. Synchrotron X-ray diffraction measurements were made on the samples from 12K to temperatures above their ferroelectric-paraelectric transition points with 10K measurement steps. Rietveld refinement using FULLPROF suite was used to refine the patterns. Depending on the composition and temperature, rhomhohedral phases, orthorhombic phases, tetragonal phases, cubic phases and two-phase mixtures were obtained. R3c (161), Amm2 (38), P4mm (99), (221) space...

Untersuchungen des mit Phasenwechsel verbundenen instationären Transports von Wasser in Isolierungen

Andreas Joos
In vielen Anwendungsbereichen existiert die Notwendigkeit das Eindringen von Wasserdampf in poröse Stoffe und den Phasenwechsel zu Wasser oder Eis sowie die Rücktrocknung vorauszusagen. Um verlässliche Vorhersagen zur Dynamik dieser Transportprozesse treffen zu können, sind validierte mathematische Modelle notwendig. Diese setzen zum einen ein gutes Verständnis und eine problemorientierte Bewertung der auftretenden physikalischen Vorgänge, zum anderen belastbare Messdaten voraus. In dieser Arbeit wird diese Problematik am Beispiel der Flugzeugisolierung diskutiert.

Dritter Interdisziplinärer Workshop Maritime Systeme : aktuelle Ergebnisse aus laufenden Promotionsprojekten an der TUHH

Martin Heinig, Hendrik Dankowski, Lennart Pundt, Katja Wöckner-Kluwe & Jörg Brunswig
Kurzberichte zum Dritten Interdisziplinären Workshop Maritime Systeme

Content management and knowledge management : two faces of ontology-based deep-level interpretation of text

Irma Sofia Espinosa Peraldi
In order to make content management systems able to exploit annotations about content semantics for the management of content, this work proposes an approach for text interpretation that is built on the principles of logic-based abduction. The approach is presented in the context of a framework that allows for a deep-level interpretation of text. The research contributions of this work encompass (1) a framework for the integration of shallow-processing techniques of text with logic-based techniques...

The Blue Engineer : IngenieurInnen mit ökologischer und sozialer Verantwortung. Ausgabe 01, Wintersemester 2011/2012

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.

Resource Types

  • Text
    54

Publication Year

  • 2011
    54

Registration Year

  • 2018
    4
  • 2017
    2
  • 2016
    1
  • 2015
    47