TY  - JOUR
A1  - Grotendorst, Johannes
T1  - IAS Winter School: Hierarchical Methods for Dynamics in Complex Molecular Systems
JF  - Innovatives Supercomputing in Deutschland : inSiDE. 10 (2012), H. 1
Y1  - 2012
SP  - 104
PB  - -
ER  - 
TY  - JOUR
A1  - Nomdedeu, Mar Monsonis
A1  - Willen, Christine
A1  - Schieffer, Andre
A1  - Arndt, Hartmut
T1  - Temperature-dependent ranges of coexistence in a model of a two-prey-one-predator microbial food web
JF  - Marine Biology
N2  - The objective of our study was to analyze the effects of temperature on the population dynamics of a three-species food web consisting of two prey bacteria (Pedobacter sp. and Acinetobacter johnsonii) and a protozoan predator (Tetrahymena pyriformis) as model organisms. We assessed the effects of temperature on the growth rates of all three species with the objective of developing a model with four differential equations based on the experimental data. The following hypotheses were tested at a theoretical level: Firstly, temperature changes can affect the dynamic behavior of a system by temperature-dependent parameters and interactions and secondly, food web response to temperature cannot be derived from the single species temperature response. The main outcome of the study is that temperature changes affect the parameter range where coexistence is possible within all three species. This has significant consequences on our ideas regarding the evaluation of effects of global warming.
Y1  - 2012
U6  - https://doi.org/10.1007/s00227-012-1966-x
SN  - 1432-1793
VL  - 159
IS  - 11
SP  - 2423
EP  - 2430
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Hötter, Jan-Steffen
A1  - Fateri, Miranda
A1  - Gebhardt, Andreas
T1  - Prozessoptimierung des SLM-Prozesses mit hoch-reflektiven und thermisch sehr gut leitenden Materialien durch systematische Parameterfindung und begleitende Simulationen am Beispiel von Silber
JF  - RTejournal - Forum für Rapid Technologie
N2  - Additive Manufacturing durch Aufschmelzen von Metallpulvern hat sich auf breiter Front als Herstellverfahren, auch für Endprodukte, etabliert. Besonders für die Variante des Selective Laser Melting (SLM) sind Anwendungen in der Zahntechnik bereits weit verbreitet und der Einsatz in sensitiven Branchen wie der Luftfahrt ist in greifbare Nähe gerückt. Deshalb werden auch vermehrt Anstrengungen unternommen, um bisher nicht verarbeitete Materialien zu qualifizieren. Dies sind vorzugsweise Nicht-Eisen- und Edelmetalle, die sowohl eine sehr hohe Reflektivität als auch eine sehr gute Wärmeleitfähigkeit aufweisen – beides Eigenschaften, die die Beherrschung des Laser-Schmelzprozesses erschweren und nur kleine Prozessfenster zulassen. Die Arbeitsgruppe SLM des Lehr- und Forschungsgebietes Hochleistungsverfahren der Fertigungstechnik hat sich unter der Randbedingung einer kleinen und mit geringer Laserleistung ausgestatteten SLM Maschine der Aufgabe gewidmet und am Beispiel von Silber die Parameterfelder für Einzelspuren und wenig komplexe Geometrien systematisch untersucht. Die Arbeiten wurden von FEM Simulationen begleitet und durch metallographische Untersuchungen verifiziert. Die Ergebnisse bilden die Grundlage zur schnellen Parameterfindung bei komplexen Geometrien und bei Veränderungen der Zusammensetzung, wie sie bei zukünftigen Legierungen zu erwarten sind. Die Ergebnisse werden exemplarisch auf unterschiedliche Geometrien angewandt und entsprechende Bauteile gezeigt.
N2  - Additive manufacturing by melting of metal powders is a method that has been established even for the manufacturing of final products. In particular, Selective Laser Melting (SLM) is currently applied for prosthetic dentistry. In the near future, this technology will access sensitive industries like aerospace engineering. This leads to the need to process new materials. Therefore, especially non-ferrous metals and noble metals must be determined and qualified. These materials have in common a very high reflectivity and an excellent thermal conductivity. In general, these two properties counteract the control of the melt pool and contribute to very narrow process windows. The “SLM” research team of the Aachen University of Applied Science, AcUAS (FH Aachen) systematically investigated process parameter fields for silver. The work focused on a small SLM desktop machine with comparably low laser power. The results are verified using FEA and metallographic inspections and will support future set-ups for complex geometries. Furthermore, the obtained parameter fields are applied to make different geometric objects and to manufactured parts, which are presented.
KW  - SLM
KW  - Selektives Laser Schmelzen
KW  - Silber
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0009-2-33639
SN  - 1614-0923
VL  - 9
IS  - 1
SP  - 1
EP  - 14
PB  - Fachhoschule Aachen
CY  - Aachen
ER  - 
TY  - JOUR
A1  - Lustfeld, H.
A1  - Pithan, C.
A1  - Reißel, Martin
T1  - Metallic electrolyte composites in the framework of the brick-layer model
JF  - Journal of the European Ceramic Society
N2  - It is well known that the already large dielectric constants of some electrolytes like BaTiO₃ can be enhanced further by adding metallic (e.g. Ni, Cu or Ag) nanoparticles. The enhancement can be quite large, a factor of more than 1000 is possible. The consequences for the properties will be discussed in the present paper applying a brick-layer model (BLM) for calculating dc-resistivities of thin layers and a modified one (PBLM) that includes percolation for calculating dielectric properties of these materials. The PBLM results in an at least qualitative description and understanding of the physical phenomena: This model gives an explanation for the steep increase of the dielectric constant below the percolation threshold and why this increase is connected to a dramatic decrease of the breakdown voltage as well as the ability of storing electrical energy. We conclude that metallic electrolyte composites like BaTiO₃ are not appropriate for energy storage.
Y1  - 2012
U6  - https://doi.org/10.1016/j.jeurceramsoc.2011.10.017
SN  - 0955-2219
VL  - 32
IS  - 4
SP  - 859
EP  - 864
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kern, Alexander
A1  - Schelthoff, Christof
A1  - Mathieu, Moritz
T1  - Detaillierte Berechnung der Einfangwirksamkeiten von Fangeinrichtungen
JF  - Elektro-Praktiker
N2  - Im Beitrag wird zunächst das Verfahren eines dynamischen elektro-geometrischen Modells vorgestellt. Dieses arbeitet im Gegensatz zum klassischen Blitzkugel-Verfahren nicht mit konstanten Radien; vielmehr wird der Radius der Blitzkugel variiert. Dabei werden ausschließlich vorhandene und in internationalen Normen anerkannte Ergebnisse, blitzphysikalische Grundlagen und Untersuchungen verwendet, und auf deren Grundlage ein numerisches Verfahren erarbeitet. Mit dem dynamischen elektro-geometrischen Modell werden dann einige Beispiele des Schutzes mit Fangstangen, die gemäß dem klassischen Blitzkugel-Verfahren nach DIN EN 62305-3 für die Schutzklassen I – II – III – IV geplant sind, untersucht. Es wird gezeigt, dass die Einfangwirksamkeiten wesentlich höher sind als in der Normenreihe DIN EN 62305 selbst angegeben. Grund dafür ist die Tatsache, dass das Blitzkugel-Verfahren sehr konservativ aufgebaut ist und dem Planer von Blitzschutzsystemen nur die möglichen Stellen für einen Einschlag aufzeigt, ohne eine Bewertung der Einschlagshäufigkeit zu liefern. Andererseits bedeutet dies jedoch, dass man mit dem klassischen Blitzkugel-Verfahren stets auf der „sicheren Seite“ liegt.
Y1  - 2012
SN  - 0013-5569
VL  - 66
IS  - 4
PB  - Huss Medien
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Schuba, Marko
A1  - Höfken, H.
A1  - Schaefer, T.
T1  - Smartphone Forensik
JF  - Hakin9 : Practical Protection  (2012)
Y1  - 2012
SN  - 1733-7186
SP  - 10
EP  - 20
PB  - -
ER  - 
TY  - JOUR
A1  - Leurs, Ulrike
A1  - Mezo, Gabor
A1  - Öhlschläger, Peter
A1  - Orban, Erika
A1  - Marquard, Andrea
A1  - Manea, Marilena
T1  - Design, synthesis, in vitro stability and cytostatic effect of multifunctional anticancer drug-bioconjugates containing GnRH-III as a targeting moiety
JF  - Peptide Science
N2  - Bioconjugates containing the GnRH-III hormone decapeptide as a targeting moiety are able to deliver chemotherapeutic agents specifically to cancer cells expressing GnRH receptors, thereby increasing their local efficacy while limiting the peripheral toxicity. However, the number of GnRH receptors on cancer cells is limited and they desensitize under continuous hormone treatment. A possible approach to increase the receptor mediated tumor targeting and consequently the cytostatic effect of the bioconjugates would be the attachment of more than one chemotherapeutic agent to one GnRH-III molecule. Here we report on the design, synthesis and biochemical characterization of multifunctional bioconjugates containing GnRH-III as a targeting moiety and daunorubicin as a chemotherapeutic agent. Two different drug design approaches were pursued. The first one was based on the bifunctional [4Lys]-GnRH-III (Glp-His-Trp-Lys-His-Asp-Trp-Lys-Pro-Gly-NH2) containing two lysine residues in positions 4 and 8, whose ϵ-amino groups were used for the coupling of daunorubicin. In the second drug design, the native GnRH-III (Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH2) was used as a scaffold; an additional lysine residue was coupled to the ϵ-amino group of 8Lys in order to generate two free amino groups available for conjugation of daunorubicin. The in vitro stability/degradation of all synthesized compounds was investigated in human serum, as well as in the presence of rat liver lysosomal homogenate. Their cellular uptake was determined on human breast cancer cells and the cytostatic effect was evaluated on human breast, colon and prostate cancer cell lines. Compared with a monofunctional compound, both drug design approaches resulted in multifunctional bioconjugates with increased cytostatic effect.
Y1  - 2012
U6  - https://doi.org/10.1002/bip.21640
SN  - 1097-0282
VL  - 98
IS  - 1
SP  - 1
EP  - 10
PB  - Wiley
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Grinsven, Bart van
A1  - Bon, Natalie vanden
A1  - Strauven, Hannelore
A1  - Grieten, Lars
A1  - Murib, Mohammed
A1  - Jiménez Monroy, Kathia L.
A1  - Janssens, Stoffel D.
A1  - Haenen, Ken
A1  - Schöning, Michael Josef
A1  - Vermeeren, Veronique
A1  - Ameloot, Marcel
A1  - Michiels, Luc
A1  - Thoelen, Ronald
A1  - Ceuninck, Ward de
A1  - Wagner, Patrick
T1  - Heat-Transfer Resistance at Solid-Liquid Interfaces: A Tool for The Detection of Single Nucleotide Polymorphisms in DNA.
JF  - ACS Nano
N2  - In this article, we report on the heat-transfer resistance at interfaces as a novel, denaturation-based method to detect single-nucleotide polymorphisms in DNA. We observed that a molecular brush of double-stranded DNA grafted onto synthetic diamond surfaces does not notably affect the heat-transfer resistance at the solid-to-liquid interface. In contrast to this, molecular brushes of single-stranded DNA cause, surprisingly, a substantially higher heat-transfer resistance and behave like a thermally insulating layer. This effect can be utilized to identify ds-DNA melting temperatures via the switching from low- to high heat-transfer resistance. The melting temperatures identified with this method for different DNA duplexes (29 base pairs without and with built-in mutations) correlate nicely with data calculated by modeling. The method is fast, label-free (without the need for fluorescent or radioactive markers), allows for repetitive measurements, and can also be extended toward array formats. Reference measurements by confocal fluorescence microscopy and impedance spectroscopy confirm that the switching of heat-transfer resistance upon denaturation is indeed related to the thermal on-chip denaturation of DNA.
Y1  - 2012
U6  - https://doi.org/10.1021/nn300147e
SN  - 1936-086X
VL  - 6
IS  - 3
SP  - 2712
EP  - 2721
PB  - ACS Publications
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Timme, Michael
A1  - Günnewig, Sebastian
T1  - Betriebskostenabrechnung - Die Pflicht des Vermieters zur Beachtung des Wirtschaftlichkeitsgebots
JF  - Der Miet-Rechts-Berater : MietRB ; Miete, Immobilien, Wohnungseigentum
N2  - Mit seiner aktuellen Entscheidung (BGH v. 6.11.2011 – VIII ZR 340/10, MDR 2011, 1095 = MietRB MDR 2011, 337) hat der BGH die Darlegungs- und Beweislast für einen Verstoß gegen das Gebot der Wirtschaftlichkeit bei der Abrechnung von Betriebskosten konkretisiert. Der Beitrag erläutert anhand der Hintergründe des Gebotes der Wirtschaftlichkeit die Konsequenzen für die Praxis.
Y1  - 2012
SN  - 1612-040X
IS  - 3
SP  - 83
EP  - 88
PB  - Verlag Dr. Otto Schmidt
CY  - Köln
ER  - 
TY  - JOUR
A1  - Schneider, Bettina
A1  - Schneider, Wilhelm
T1  - Externes Rechnungswesen nach BilMoG: Grundelemente und Aufbau
JF  - Das Wirtschaftsstudium : wisu ; Zeitschrift für Ausbildung, Examen, Berufseinstieg und Fortbildung
Y1  - 2012
SN  - 0340-3084
VL  - 41
IS  - 3
SP  - 332
EP  - 337
PB  - Lange
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Olaru, Alexandra Maria
A1  - Kowalski, Julia
A1  - Sethi, Vaishali
A1  - Blümich, Bernhard
T1  - Exchange relaxometry of flow at small Péclet numbers in a glass bead pack
JF  - Journal of Magnetic Resonance (JMR)
N2  - In this paper we consider low Péclet number flow in bead packs. A series of relaxation exchange experiments has been conducted and evaluated by ILT analysis. In the resulting correlation maps, we observed a collapse of the signal and a translation towards smaller relaxation times with increasing flow rates, as well as a signal tilt with respect to the diagonal. In the discussion of the phenomena we present a mathematical theory for relaxation exchange experiments that considers both diffusive and advective transport. We perform simulations based on this theory and discuss them with respect to the conducted experiments.
KW  - NMR exchange relaxometry
KW  - Low-field NMR
Y1  - 2012
U6  - https://doi.org/10.1016/j.jmr.2012.04.015
SN  - 1096-0856
VL  - 220
SP  - 32
EP  - 44
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Fischer, Jan-Thomas
A1  - Kowalski, Julia
A1  - Pudasaini, Shiva P.
T1  - Topographic curvature effects in applied avalanche modelling
JF  - Cold Regions Science and Technology
N2  - This paper describes the implementation of topographic curvature effects within the RApid Mass MovementS (RAMMS) snow avalanche simulation toolbox. RAMMS is based on a model similar to shallow water equations with a Coulomb friction relation and the velocity dependent Voellmy drag. It is used for snow avalanche risk assessment in Switzerland. The snow avalanche simulation relies on back calculation of observed avalanches. The calibration of the friction parameters depends on characteristics of the avalanche track. The topographic curvature terms are not yet included in the above mentioned classical model. Here, we fundamentally improve this model by mathematically and physically including the topographic curvature effects. By decomposing the velocity dependent friction into a topography dependent term that accounts for a curvature enhancement in the Coulomb friction, and a topography independent contribution similar to the classical Voellmy drag, we construct a general curvature dependent frictional resistance, and thus propose new extended model equations. With three site-specific examples, we compare the apparent frictional resistance of the new approach, which includes topographic curvature effects, to the classical one. Our simulation results demonstrate substantial effects of the curvature on the flow dynamics e.g., the dynamic pressure distribution along the slope. The comparison of resistance coefficients between the two models demonstrates that the physically based extension presents an improvement to the classical approach. Furthermore a practical example highlights its influence on the pressure outline in the run out zone of the avalanche. Snow avalanche dynamics modeling natural terrain curvature centrifugal force friction coefficients.
KW  - Snow
KW  - Avalanche
Y1  - 2012
U6  - https://doi.org/10.1016/j.coldregions.2012.01.005
SN  - 1872-7441
VL  - 74-75
SP  - 21
EP  - 30
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Pieper, Martin
A1  - Klein, Peter
T1  - Application of simple, periodic homogenization techniques to non-linear heat conduction problems in non-periodic, porous media
JF  - Heat mass transfer
N2  - Often, detailed simulations of heat conduction in complicated, porous media have large runtimes. Then homogenization is a powerful tool to speed up the calculations by preserving accurate solutions at the same time. Unfortunately real structures are generally non-periodic, which requires unpractical, complicated homogenization techniques. We demonstrate in this paper, that the application of simple, periodic techniques to realistic media, that are just close to periodic, gives accurate, approximative solutions. In order to obtain effective parameters for the homogenized heat equation, we have to solve a so called “cell problem”. In contrast to periodic structures it is not trivial to determine a suitable unit cell, which represents a non-periodic media. To overcome this problem, we give a rule of thumb on how to choose a good cell. Finally we demonstrate the efficiency of our method for virtually generated foams as well as real foams and compare these results to periodic structures.
Y1  - 2012
U6  - https://doi.org/10.1007/s00231-011-0879-4
SN  - 0947-7411
VL  - 48
IS  - 2
SP  - 291
EP  - 300
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Fateri, Miranda
A1  - Hötter, Jan-Steffen
A1  - Gebhardt, Andreas
T1  - Experimental and Theoretical Investigation of Buckling Deformation of Fabricated Objects by Selective Laser Melting
JF  - Physics Procedia
N2  - Although Selective Laser Melting (SLM) process is an innovative manufacturing method, there are challenges such as inferior mechanical properties of fabricated objects. Regarding this, buckling deformation which is caused by thermal stress is one of the undesired mechanical properties which must be alleviated. As buckling deformation is more observable in hard to process materials, silver is selected to be studied theoretically and experimentally for this paper. Different scanning strategies are utilized and a Finite Element Method (FEM) is applied to calculate the temperature gradient in order to determine its effect on the buckling deformation of the objects from experiments.
Y1  - 2012
U6  - https://doi.org/10.1016/j.phpro.2012.10.062
SN  - 1875-3892
N1  - Part of special issue "Laser Assisted Net shape Engineering 7 (LANE 2012)"
VL  - 39
SP  - 464
EP  - 470
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Jochim, Haldor E.
T1  - Die Ostheidebahn - eine Alternative zur Y-Trasse
JF  - ETR - Eisenbahntechnische Rundschau
Y1  - 2012
SN  - 0013-2845
VL  - 61
IS  - 11
SP  - 34
EP  - 37
PB  - DVV Media Group
CY  - Hamburg
ER  - 
TY  - JOUR
A1  - Kirstein, Simon
A1  - Müller, Karsten
A1  - Walecki-Mingers, Mark
A1  - Deserno, Thomas M.
T1  - Robust adaptive flow line detection in sewer pipes
JF  - Automation in construction
N2  - As part of a novel approach to automatic sewer inspection, this paper presents a robust algorithm for automatic flow line detection. A large image repository is obtained from about 50,000 m sewers to represent the high variability of real world sewer systems. Automatic image processing combines Canny edge detection, Hough transform for straight lines and cost minimization using Dijkstra's shortest path algorithm. Assuming that flow lines are mostly smoothly connected horizontal structures, piecewise flow line delineation is reduced to a process of selecting adjacent line candidates. Costs are derived from the gap between adjacent candidates and their reliability. A single parameter α enables simple control of the algorithm. The detected flow line may precisely follow the segmented edges (α = 0.0) or minimize gaps at joints (α = 1.0). Both, manual and ground truth-based analysis indicate that α = 0.8 is optimal and independent of the sewer's material. The algorithm forms an essential step to further automation of sewer inspection.
Y1  - 2012
U6  - https://doi.org/10.1016/j.autcon.2011.05.009
SN  - 1872-7891 (E-Journal) ; 0926-5805 (Print)
IS  - 21
SP  - 24
EP  - 31
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Blecken, Udo
A1  - Holthaus-Sellheier, Ursula
T1  - Quantitative Prognoseverfahren für Mietpreise von Bueroimmobilien am Beispiel Düsseldorf
JF  - GuG : Grundstücksmarkt und Grundstückswert
Y1  - 2012
SN  - 0938-0175
VL  - 23
IS  - 1
SP  - 12
EP  - 21
PB  - Werner
CY  - Köln
ER  - 
TY  - JOUR
A1  - Schneider, Bettina
A1  - Schneider, Wilhelm
T1  - Jahresabschluss nach BilMoG : Ansatz-, Ausweis- und Bewertungsvorschriften
JF  - Das Wirtschaftsstudium : wisu ; Zeitschrift für Ausbildung, Examen, Berufseinstieg und Fortbildung
Y1  - 2012
SN  - 0340-3084
VL  - 41
IS  - 4
SP  - 529
EP  - 535
PB  - Lange
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Spelthahn, Heiko
A1  - Kirsanov, Dmitry
A1  - Legin, Andrey
A1  - Osterrath, Thomas
A1  - Schubert, Jürgen
A1  - Zander, Willi
A1  - Schöning, Michael Josef
T1  - Development of a thin-film sensor array for analytical monitoring of heavy metals in aqueous solutions
JF  - Physica Status Solidi (a)
N2  - In industrial processes there is a variety of heavy metals (e.g., copper, zinc, cadmium, and lead) in use for wires, coatings, paints, alloys, batteries, etc. Since the application of these transition metals for industry is inevitable, it is a vital task to develop proper analytical techniques for their monitoring at low activity levels, especially because most of these elements are acutely toxic for biological organisms. The determination of ions in solution by means of a simple and inexpensive sensor array is, therefore, a promising task. In this work, a sensor array with heavy metal-sensitive chalcogenide glass membranes for the simultaneous detection of the four ions Ag⁺, Cu2⁺, Cd2⁺, and Pb2⁺ in solution is realized. The results of the physical characterization by means of microscopy, profilometry, Rutherford backscattering spectroscopy (RBS), and scanning electron microscopy (SEM) as well as the electrochemical characterization by means of potentiometric measurements are presented. Additionally, the possibility to expand the sensor array by polymeric sensor membranes is discussed.
Y1  - 2012
SN  - 1862-6319
U6  - https://doi.org/10.1002/pssa.201100733
VL  - 209
IS  - 5
SP  - 885
EP  - 891
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Spelthahn, Heiko
A1  - Schubert, Jürgen
A1  - Schöning, Michael Josef
T1  - Dünnschichtsensoren für die Schwermetallanalytik
JF  - GIT : Labor-Fachzeitschrift
N2  - Die Detektion von Schadstoffen repräsentiert in der Umweltanalytik eine wichtige Aufgabenstellung. Gerade die Abwasser- bzw. Brauchwasseranalytik sowie die Prozesskontrolle haben einen hohen Stellenwert. Siliziumbasierte Dünnschichtsensoren bieten eine kostengünstige Möglichkeit, „online“-Messungen bzw. Vor-Ort-Messungen zeitnah durchzuführen. In dieser Arbeit wird ein potentiometrisches Sensorarray auf der Basis von Chalkogenidgläsern zur Detektion von Schwermetallen in wässrigen Medien vorgestellt.
Y1  - 2012
SN  - 0016-3538
VL  - 56
IS  - 4
SP  - 285
EP  - 287
PB  - Wiley-VCH
CY  - Weinheim
ER  -