374 Works

Integrating layout planning and simulation for logistic nodes

Anne Schwientek, Ann-Kathrin Lange, Markus Holzner, Margit Thomsen & Carlos Jahn
When a new logistic node (e.g. a terminal) is planned or needs to be optimized, layout planning and simulation analysis are typically two separate tasks. While layout planning is an intuitive and visual but static approach, simulation is dynamic but more complex. Integrating both approaches would be highly beneficial. The idea of the integrated tool is to create first a static layout on a touchscreen planning table. After inserting relevant parameters and selecting preferred logistic...

Effect of nodal mass on macroscopic mechanical properties of nanoporous metals

Jingsi Jiao & Norbert Huber
The current work investigates the effect of the nodal mass on the macroscopic mechanical behavior of nanoporous metals using the Finite Element Method. A nodal corrected beam modeling concept is introduced that allows local incorporation of the effective elastoplastic mechanical behavior of the nodal mass in the nodal area of a representative volume element (RVE). The calibration to the corresponding Finite Element solid model is achieved by integrating additional geometry and material parameters to the...

Supplier Integration in Industry 4.0 – Requirements and Strategies

Julian Marius Müller, Johannes W. Veile & Kai-Ingo Voigt
Cross-company networking is essential to successfully implement Industry 4.0. In this context, numerous new demands on suppliers arise leading to integration challenges that require specific integration strategies. While these topics are important in business practice, an aggregated holistic overview is still missing. Therefore, this article examines new demands on suppliers, challenges in the implementation process, and integration strategies for supplier integration in the context of Industry 4.0. Expert interviews with 15 different industrial companies from...

A framework for the alignment of new product development and supply chains

Margherita Pero, Nizar Abdelkafi, Andrea Sianesi & Thorsten Blecker
The purpose of this paper is to develop a framework that explains how new product development and supply chain variables are related to one another and how they affect performance.

Cross-disciplinary communication among Ph.D. candidates : how to make it work

Ulrike Herzog, Alette Winter & Christian H. Kautz
Cross-disciplinary research settings are highly challenging for young scientists. In our research centre, Ph.D. candidates with various disciplinary backgrounds are expected to cooperate. To support cooperation, we designed a Ph.D. programme that fosters cross-disciplinary communication. The programme uses an innovative teaching format that aims to broaden the participants’ understanding of technical basics and to improve their academic teaching skills. Being faced with dissatisfaction among the Ph.D. candidates at first, we introduced a targeted feedback process...

Transport in nanoporous materials including MOFs : the applicability of Fick’s laws

Tobias Titze, Alexander Lauerer, Lars Heinke, Christian Chmelik, Nils E. R. Zimmermann, Frerich Keil, Douglas M. Ruthven & Jörg Kärger
Die Diffusion in nanoporösen Wirt-Gast-Systemen wird oft als viel zu kompliziert angesehen, als dass sie mit so “einfachen” Beziehungen wie dem ersten und zweiten Fickschen Gesetz vereinbar sein könnte. Wir zeigen nun, dass die mikroskopischen Diffusionsmesstechniken, vor allem die NMR-Spektroskopie mit gepulsten Feldgradienten (PFG) und die Mikrobildgebung mittels Interferenzmikroskopie (IFM) und IR-Mikroskopie (IRM), den direkten experimentellen Nachweis für die Anwendbarkeit der Fickschen Gesetze auf solche Systeme liefern. Dies gilt oft auch dann noch, wenn die...

A Comparison of German and Indian innovation pathways in the auto component industry

Katharina Kalogerakis, Luise Fischer & Rajnish Tiwari
This paper is a part of a series of analyses conducted within a BMBF-funded research project to investigate potentials of frugal innovations for Germany. One of the objectives of this project has been to identify innovation pathways that foster frugal innovations. Since auto component suppliers based in India are known to contribute significantly to the development of “affordable and good quality” vehicles, it was considered useful to conduct comparative studies of the prevalent innovation pathways...

Prekäre Privilegien - Wie Ingenieur_innen ihren Alltag gestalten

Jette Hausotter
A qualitative study based on 21 problem-centered interviews examines the impact of precarization on engineers in Germany. An empirical typology is elaborated and leads to a comparative analysis of how precarious privileges affect the everyday life of engineers and how they position themselves in conflicts between their own wishes and the social conditions. The results are evaluated regarding theories of intersectionality and social inequality, gender studies and sociology of work an employment.

Combined FEM-SPH simulations for ice in compression

Niklas Düchting
Within this chapter the outcome of the numerical investigation on a combined FEM-SPH simulation is summed up. The practical approach of this project allows only a rather sim-ple assessment and there are aspects that need to be investigated further. An outlook in-dicates possible aspects for future research. Regarding the correlation of the contact forces the results of the final simulations pre-sented in section 3.3.1 are satisfying. The ability to model the transformation of the ma-terial...

Inteins, valuable genetic elements in molecular biology and biotechnology

Skander Elleuche & Stefanie Pöggeler
Inteins are internal protein elements that self-excise from their host protein and catalyze ligation of the flanking sequences (exteins) with a peptide bond. They are found in organisms in all three domains of life, and in viral proteins. Intein excision is a posttranslational process that does not require auxiliary enzymes or cofactors. This self-excision process is called protein splicing, by analogy to the splicing of RNA introns from pre-mRNA. Protein splicing involves only four intramolecular...

On the direct kinematics problem of parallel mechanisms

Arthur Seibel, Stefan Schulz & Josef Schlattmann
The direct kinematics problem of parallel mechanisms, that is, determining the pose of the manipulator platform from the linear actuators’ lengths, is, in general, uniquely not solvable. For this reason, instead of measuring the lengths of the linear actuators, we propose measuring their orientations and, in most cases, also the orientation of the manipulator platform. This allows the design of a low-cost sensor system for parallel mechanisms that completely renounces length measurements and provides a...

Elastic and plastic poisson’s ratios of nanoporous gold

Lukas Lührs, Celal Soyarslan, Jürgen Markmann, Swantje Bargmann & Jörg Weißmüller
We explore the elastic and plastic Poisson’s ratios, mE and mP, of nanoporous gold, using digital image correlation during compression experiments including load/unload segments. The two coefficients differ significantly, with mE independent of the ligament size, L, and with a trend for mP / L at not too large L. Disorder in the network of ligaments may explain why mE is smaller than predicted by lattice-based models. Finite element simulations, based on the Deshpande–Fleck constitutive...

RUVIVAL Publication Series Volume 3

Joachim Behrendt, Dario Fröndhoff, Andrea Munoz Ardila, Maria Monina Orlina, Máryeluz Rueda Morales & Ruth Schaldach
RUVIVAL Publication Series is a compilation of literature reviews on topics concerned with the revitalisation of rural areas. RUVIVAL Publication Series is part of the e-learning project RUVIVAL and each of the three contributions in this publication is connected to further interactive multimedia material, which can be reached under www.ruvival.de. The first literature review is concerned with urine utilisation as a fertiliser in agriculture. Urine contains four important nutrients for plant growth: nitrogen (N), phosphorus...

Gypsum scaling during reverse osmosis desalination − characterization and effects of natural organic matter

Jan Benecke
Desalination of brackish and salty water by reverse osmosis (RO) has been increasingly applied to address regional water shortages. Especially at high water recovery, the crystallization of sparingly soluble salts near or on the membrane surface (‘scaling’) is a serious limitation during RO operation. This dissertation characterizes scaling by gypsum (CaSO4∙2H2O) and its interactions with natural organic matter (NOM) in cross-flow RO and stirred beaker crystallization experiments. The results show that gypsum scaling and associated...

Impact of managerial risk-taking and IRM ‎on innovation

Fatemeh Seidiaghilabadi, Ebrahim Abbassi & Zahra Seidiaghilabadi
Innovation in any business comes with risk. This study aimed to explore the role of managerial risk-taking and integrated risk management (IRM) on innovation. To verify the hypotheses, a questionnaire was designed. Data were collected from 109 Insurance Managers from Iran Insurance Companies. PLS structural equation modeling was employed to test both measurement and structural model. The results demonstrate that integrated risk management and managers’ risktaking have a positive impact on innovation. This is the...

Low-latency audio over IP on embedded systems

Florian Meier
Übertragung von Audiodaten über Netzwerke wie das Internet ist eine weitverbreitete Technology. Bis jetzt ist die hauptsächliche Anwendung die Übertragung von menschlicher Stimme (Voice over IP). Obwohl moderne Voice over IP Systeme dafür ausgelegt sind Latenz zu reduzieren, ist diese immer noch zu groß um bidirektional Livemusik zu übertragen. Die Entwicklung einer Musikumgebung mit niedriger Latenz würde verteilte Musikaufführungen, sowie "Jamming over IP" erlauben. Diese Arbeit geht einen Schritt in diese Richtung in dem ein...

LWE-based encryption schemes and their applications In privacy-friendly data aggregation

Daniela Becker
Wir konstruieren neue Verschlüsselungssysteme basierend auf dem Learning With Errors Problem and lösen die folgenden Probleme: Durch datenschutzfreundliche Aggregation lassen sich Daten von mehreren Nutzern unter Wahrung ihrer Privatsphäre aggregieren ohne dem Aggregator zu vertrauen. Unsere Systeme verbessern sowohl Laufzeit als auch Bandbreite der Verschlüsselung, insbesondere die Entschlüsselung ist ca. 150 Mal schneller als zuvor. Überdies stellen wir die erste Lösung für datenschutzfreundliche Werbung auf sozialen Medien vor - unsere Architektur hat hohe Sicherheits- und...

Automatic three-dimensional geometry and mesh generation of periodic representative volume elements for matrix-inclusion composites

Konrad Schneider, Benjamin Klusemann & Swantje Bargmann
This paper introduces an efficient method to automatically generate and mesh a periodic three- dimensional microstructure for matrix-inclusion composites. Such models are of major importance in the field of computational micromechanics for homogenization purposes utilizing unit cell models. The main focus of this contribution is on the creation of cubic representative volume elements (RVEs) featuring a periodic geometry and a periodic mesh topology suitable for the application of periodic boundary condi- tions in the framework...

Effect of La and Mn on the properties of alkaline niobate-based piezoelectric ceramics

Henry Ekene Mgbemere & Gerold A. Schneider
Lead-free ferroelectric (K0.44Na0.52Li0.04)(Nb0.86Ta0.1Sb0.04)O3ceramics co-doped with different amounts of both La and Mn have been produced using solid-state synthesis method. The relative density values of the unmodified sample are between 92 and 96% and decreases to ~91% for the sample with 1 mol% of the co-doping. Bi-modal grain distribution is observed in the samples while the average grain size decreases with co-doping due to grain growth inhibition by pinning of the grain boundary movement. The diffraction...

Bauteilqualität und Werkzeugverschleiß beim Fräsen von CFK-Gelege unter räumlichen Eingriffsbedingungen

Felix Brügmann
Durch Modellierung der räumlichen Eingriffsbedingungen sowie der Faserüberstände in Abhängigkeit von der Bauteilkontur wurden der Einfluss auf die Schnittqualität beim Fräsen von CFK-Gelege analysiert und optimierte Frässtrategien abgeleitet. Zudem wurde der Einfluss des Faserorientierungswinkels auf den Werkzeugverschleiß beim Fräsen im Vollschnitt nachgewiesen und mittels eines empirischen Modells durch Hobelversuche untersucht.

Lessons learned from early clinical experience and results of 300 ASR hip resurfacing implantations

Thomas Siebel, Stefan Maubach & Michael Morlock
Between August 2003 and April 2005, 300 ASR metal-on-metal resurfacing hip endoprostheses were implanted by the first author and a fellow surgeon. The mean age at surgery was 56.8 years (18-75.9 years) and mean body mass index was 27.6 kg/m2 (range, 19-41 kg/m2). The mean follow-up time was 202 days. The mean Harris hip score improved from 44 pre-operatively to 89 at 3 months post-operatively. In total, eight (2.7 per cent) cases [five neck fractures...

Piezoelectric gold : strong charge-load response in a metal-based hybrid nanomaterial

Charlotte Stenner, Li-Hua Shao, Nadiia Mameka & Jörg Weißmüller
Impregnating the pores of nanoporous gold with aqueous electrolyte yields a hybrid nanomaterial with two separate and interpenetrating charge transport paths, electronic conduction in the metal and ionic conduction in the electrolyte. As the two paths are capacitively connected, space‐charge layers along the internal interfaces are coupled to electric potential differences between the paths and can be controlled or detected thereby. The present experiments show that the space charge couples to mechanical deformation of the...

A method to simplify perturbation analyses of periodical flows

Heinrich Söding
Perturbation methods up to first order with respect to motion or wave amplitude are common in seakeeping predictions. For higher than first order, lengthy theoretical analyses are required. They result in complicated formulae requiring high programming effort, and often the well-established numerical methods for first-order quantities fail when applied to second-order flow quantities. Both the derivation of the required expressions and their programming are simplified by using mathematical entities called perturbators. The concept of perturbators...

Advanced calculation of the room-temperature shapes of unsymmetric laminates

Mathias Schlecht & Karl Schulte
It is well known that the room-temperature shapes of unsymmetric laminates do not always conform to the predictions of classical lamination theory. Instead of being saddle shaped, as classical lamination theory predicts, the room-temperature shapes of unsymmetrically laminated composites are often cylindrical in nature. In addition, a second cylindrical shape can sometimes be obtained from the first by a simple snap-through action. Since 1981 several models, which are restricted to rectangular plates and sometimes only...

Common beliefs and reality about PLS : comments on Rönkkö and Evermann (2013)

Jörg Henseler, Theo K. Dijkstra, Marko Sarstedt, Christian M. Ringle, Adamantios Diamantopoulos, Detmar W. Straub, David J. Ketchen, Joseph F. Hair, G. Tomas M. Hult & Roger J. Calantone
This article addresses Ro¨nkko¨ and Evermann’s criticisms of the partial least squares (PLS) approach to structural equation modeling. We contend that the alleged shortcomings of PLS are not due to problems with the technique, but instead to three problems with Ro¨nkko¨ and Evermann’s study: (a) the adherence to the common factor model, (b) a very limited simulation designs, and (c) overstretched generalizations of their findings. Whereas Ro¨nkko¨ and Evermann claim to be dispelling myths about...

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  • 2018

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