2,150 Works

Nutzung regionaler abfall- und abwasserstämmiger Bioressourcen am Beispiel des Hamburger Demonstrationsvorhabens „Jenfelder Au“ : Inventur, Lagerung, Aufbereitung, Vergärung und Gärrestverwertung

Saskia Hertel & Ina Körner
Im vorliegenden Forschungsbericht werden Arbeiten und Ergebnisse vorgestellt, die im Rahmen des vom BMBF geförderten Verbundprojektes KREIS (Kopplung von regenerativer Energiegewinnung mit innovativer Stadtentwässerung) erstellt wurden (Förderkennzeichen 033L047C). KREIS bereitete die Umsetzung des von Hamburg Wasser entwickelten Hamburg Water Cycle® (HWC) in einem Neubaugebiet in Hamburg vor. Der HWC sieht die getrennte Erfassung von Regen-, Grau- und Schwarzwasser und eine dezentrale Behandlung der drei Abwasserströme vor. Die Arbeiten der TUHH umfassten dabei den Bereich der...

Elastic behaviour at the nanoscale of innovative composites of nanoporous gold and polymer

Emma Griffiths, Swantje Bargmann & B. Dayanand Reddy
Nanoporous gold is a material with unique properties that make it attractive for use in multiple areas. It has an extremely high compressive strain capability but is very brittle in tension which limits its usage. One means of addressing this limitation is to fill the voids of the nanoporous material with a polymer, resulting in a more ductile and stronger material. In this work, the mechanical properties of a nanocomposite representative sample are studied numerically....

Finite volume evolution Galerkin (FVEG) methods for hyperbolic systems

Mária Medviďová-Lukáčová, Keith W. Morton & Gerald Warnecke
The subject of the paper is the derivation and analysis of new multidimensional, high-resolution, finite volume evolution Galerkin (FVEG) schemes for systems of nonlinear hyperbolic conservation laws. Our approach couples a finite volume formulation with approximate evolution operators. The latter are constructed using the bicharacteristics of the multidimensional hyperbolic system, such that all of the infinitely many directions of wave propagation are taken into account. In particular, we propose a new FVEG-scheme, which is designed...

Extension of the contour integral method for the electrical design of planar structures in digital systems

Xiaomin Duan
The fast-paced evolution of the semiconductor industry is putting forth great challenges on electronic design automation tools. This thesis focuses on the efficient and accurate modeling of planar structures and power planes in digital systems by the extension of a fast two-dimensional numerical technique, the contour integral method. The extension includes the derivation of analytical expressions for rapid analysis of cylindrical vias as well as the combination with other efficient approaches for handling of complex...

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...

A transformational approach to generic software development based on higher-order, typed functional signatures

Daniel Lincke
This thesis introduces a method based on program transformation for developing generic software libraries. More precisely, the signatures of generic functions, i.e., functions parameterised on types, are transformed from a functional language to an object-oriented language. Type level functional constructs, such as higher-order functions and type constructors, are mapped to type parameters specified using a mechanism called concepts. The transformation is independent from particular languages and can be formally described.

Pharmaceutical Residues in Urine and Potential Risks related to Usage as Fertiliser in Agriculture

Martina Winker
Aim of this study was to determine the potential risks of pharmaceuticals contained in urine when used as fertiliser by means of a database and by greenhouse experiments. Pharmaceutical concentrations in average German urine could be identified by consumption and pharmacokinetic data and were related to concentrations found in wastewater as well as separately colleted urine. Certain pharmaceuticals persist in soil and are taken up by plants, a potential concern with respect to urine fertilisation.

TUHH Spektrum Oktober 2007

Präsident Der Technischen Universität Hamburg-Harburg
Kühne School of Logistics and Management (KSL), Forschungsschwerpunkte der TUHH, Medizintechnik, Lean production und Supply Chain in der Automobilindustrie, Starthilfe für Erstsemester, Neue Bachelor- und Master-Studiengänge, Kinderforscher an der TUHH

Synthetic pathways and processes for effective production of 5-hydroxytryptophan and serotonin from glucose in Escherichia coli

José Aníbal Mora-Villalobos & An-Ping Zeng
Tryptophan derivatives such as 5-hydroxytryptophan (5HTP) and serotonin are valuable molecules with pharmaceutical interest. 5HTP is presently mainly obtained by extraction from the plant Griffonia simplicifolia and serotonin is produced by chemical synthesis. A simple biotechnological method for the production of these compounds is desired.

Effect of different interval lengths in a rolling horizon MILP unit commitment with non-linear control model for a small energy system

Gerrit Erichsen, Tobias Zimmermann & Alfons Kather
In this paper, a fixed electricity producer park of both a short- and long-term renewable energy storage (e.g., battery, power to gas to power) and a conventional power plant is combined with an increasing amount of installed volatile renewable power. For the sake of simplicity, the grid is designed as a single copper plate with island restrictions and constant demand of 1000 MW; the volatile input is deducted from scaled 15-min input data of German...

Extraction of oil and minor compounds from oil palm fruit with supercritical carbon dioxide

Huan Phan Tai & Gerd Brunner
A significant quantity of tocochromanols and carotenoids remains in the residual from palm oil production by traditional screw pressing. Supercritical carbon dioxide extraction was used as alternative method with the purpose to recover better these valuable minor compounds. Total oil yield and co-extracted water were investigated in the course of extraction. Tocochromanols and carotenoids were evaluated, not only in the extraction oil, but also in the oil of residual fibre. Modelling of extraction process was...

Prediction of thermal exposure and mechanical behavior of epoxy resin using artificial neural networks and Fourier transform infrared spectroscopy

Audrius Doblies, Benjamin Boll & Bodo Fiedler
Thermal degradation detection of cured epoxy resins and composites is currently limited to severe thermal damage in practice. Evaluating the change in mechanical properties after a short-time thermal exposure, as well as estimating the history of thermally degraded polymers, has remained a challenge until now. An approach to accurately predict the mechanical properties, as well as the thermal exposure time and temperature of epoxy resin, using Fourier-transform infrared spectroscopy (FTIR)-spectroscopy, data processing, and artificial neural...

Drivers of sustainable supply chain management : identification and classification

Muhammad Amad Saeed & Wolfgang Kersten
With the increase in awareness of environmental and social issues associated with the development and the use of products, stakeholders - especially consumers - are showing more concern regarding these issues. To address new developments and changing trends, organizations are now compelled to identify and implement innovative and sustainable solutions, not only within their organizations’ boundaries, but also across the whole supply chain network. The primary goal of this paper was to identify and analyze...

Porous starch materials via supercritical- and freeze-drying

Victor Baudron, Pavel Gurikov, Irina Smirnova & Steve Whitehouse
The production of porous materials based on starch has been explored with supercritical drying - yielding aerogel - and freeze-drying. The two drying procedures were applied on the same gelling solution of amylomaize starch pasted at 140 °C and for two concentrations (5 and 10 wt.%). After gelation and retrogradation, water from the samples to be supercritically dried was exchanged to ethanol. The resulting starch aerogel presented high specific surface area (197 m2/g). Freeze-drying was...

Carbon nanoparticles’ impact on processability and physical properties of epoxy resins : a comprehensive study covering rheological, electrical, thermo-mechanical, and fracture properties (mode I and II)

Hauke Meeuw, Johann Körbelin, Valea Kim Wisniewski, Ali Shaygan Nia, Adrián Romaní Vázquez, Martin Rudolf Lohe, Xinliang Feng & Bodo Fiedler
A trade-off between enhancement of physical properties of the final part and the processability during manufacturing always exists for the application of nanocarbon materials in thermoset-based composites. For different epoxy resins, this study elaborates the impact of nanocarbon particle type, functionalization, and filler loading on the resulting properties, i.e., rheological, electrical, thermo-mechanical, as well as the fracture toughness in mode I and mode II loading. Therefore, a comprehensive set of carbon nanoparticles, consisting of carbon...

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.

Active vibration control using the centrifugal forces of eccentrically rotating masses

Richard Bäumer
In this PhD thesis, active vibration control using eccentrically rotating masses is investigated. The basic layout of the so-called twin rotor damper (TRD) consists of two eccentric control masses rotating about two parallel axes. In a preferred mode of op-eration, the continuous rotation mode, both control masses rotate in opposite direction with a constant angular velocity. Under further operational constraints, the generated centrifugal forces superimpose to a harmonic control force in a single direction. The...

Einfluss von heterogenen Permeabilitätsfeldern auf die CO2-Speicherung in salinen Aquiferen am Beispiel vom Pilotstandort Ketzin

Ursula Lengler
Reservoire mit geringer Mächtigkeit besitzen potentielle Kapazität für die CO2-Speicherung. In diesen hat die natürliche Heterogenität der Permeabilität einen großen Einfluss auf die laterale Reichweite der CO2-Ausbreitung. Ankunftszeiten und die mittlere Mächtigkeit der CO2-Phase werden von ihr bestimmt. Das von der CO2-Phase beanspruchte Reservoirvolumen wird von der Heterogenität vergleichsweise wenig beeinflusst und damit auch die Anteile an den Rückhaltemechanismen sowie die mittlere CO2-Sättigung. Teilweise haben horizontale und vertikale Heterogenität einen gegenläufigen Einfluss, jedoch überwiegen in...

Informationskompetenz in sich ständig verändernden Informationsumgebungen – Zum Kern von Informationskompetenz

Thomas Hapke
Über das Social Web hinaus gibt es eine Vielzahl von Veränderungen in modernen Informationsumgebungen, die Einfluss auf Konzeption und Praxis der Förderung von Informationskompetenz haben. Durch das Angebot sogenannter Discovery-Systeme und die Pflege von Link Resolvern versuchen Bibliotheken, mit ihren Beständen und Services durch die Nutzung von Suchmaschinen sichtbar zu bleiben. Eine von der Akteur-Netzwerk-Theorie inspirierte Betrachtung von Discovery-Systemen zeigt, dass für die (soziale) Konstruktion von Suchergebnissen die Informationskompetenz in Form von Recherchekompetenz der ein...

Informationskompetenz anders denken - zum epistemologischen Kern von "information literacy"

Thomas Hapke
After a critical view on information literacy (IL) as concept and as practice, this essay emphasizes its reference to academic research and writing respectively to the research process. As part of the core of IL within academic disciplinary cultures appears an epistemological component - an „epistemic literacy“. IL is part of academic „Bildung“. Reflecting on information is part of the core of any IL. In the academic area this implies reflection about science as phenomenon,...

Photocrosslinkable polysaccharide hydrogel composites based on dextran or pullulan-amylose blends with cytokines for a human co-culture model of human osteoblasts and endothelial cells

Ulrike Ritz, Peter Kögler, Isabel Höfer, Petra Frank, Sven Klees, Sören Gebhard, Christian Brendel, Kerstin Kaufmann, Alexander Hofmann, Pol Maria Rommens & Ulrich Jonas
Although a large body of research has been devoted to biomaterial development for bone tissue engineering and related medical disciplines in the last few years, novel and optimized materials especially for bone fractures of critical sizes demand continued development. In this respect, polysaccharide-based hydrogels demonstrate beneficial properties and fulfill the main requirements for a bone tissue scaffold as they are hydrophilic, biocompatible, and biodegradable. The aim of the present study was the development of a...

Theoretical and practical issues that are relevant when scaling up hMSC microcarrier production orocesses

Valentin Jossen, Cedric Schirmer, Dolman Mostafa Sindi, Regine Eibl, Matthias Kraume, Ralf Pörtner & Dieter Eibl
The potential of human mesenchymal stem cells (hMSCs) for allogeneic cell therapies has created a large amount of interest. However, this presupposes the availability of efficient scale-up procedures. Promising results have been reported for stirred bioreactors that operate with microcarriers. Recent publications focusing on microcarrier-based stirred bioreactors have demonstrated the successful use of Computational Fluid Dynamics (CFD) and suspension criteria (N S1u , N S1) for rapidly scaling up hMSC expansions from mL- to pilot...

Fredholm Theory with Applications to Random Operators

Raffael Hagger
This thesis is concerned with the Fredholm theory of bounded linear operators acting on Banach space valued sequence spaces. As an application, random operators are considered and studied in detail. One of the most important tools in the study of operators on sequence spaces is the concept of limit operators. The correspondence between an operator and its limit operators is studied regarding properties like spectrum, pseudospectrum and numerical range. It turns out that similar theorems...

Influence of process parameters on the quality of aluminium alloy en AW 7075 using Selective Laser Melting (SLM)

Niko Kaufmann, Muhammed Imran, Tim Marten Wischeropp, Claus Emmelmann, Shafaqat Siddique & Frank Walther
Selective laser melting (SLM) is an additive manufacturing process, forming the desired geometry by selective layer fusion of powder material. Unlike conventional manufacturing processes, highly complex parts can be manufactured with high accuracy and little post processing. Currently, different steel, aluminium, titanium and nickel-based alloys have been successfully processed; however, high strength aluminium alloy EN AW 7075 has not been processed with satisfying quality. The main focus of the investigation is to develop the SLM...

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