3,447 Works

The effect of random wind forcing in the nonlinear Schrödinger equation

Leo Dostal
The influence of a strong and gusty wind field on ocean waves is investigated. How the random wind affects solitary waves is analyzed in order to obtain insights about wave generation by randomly time varying wind forcing. Using the Euler equations of fluid dynamics and the method of multiple scales, a random nonlinear Schrödinger equation and a random modified nonlinear Schrödinger equation are obtained for randomly wind forced nonlinear deep water waves. Miles theory is...

Thermodynamic assessment of the fixed-bed downdraft gasification process of fallen leaves pelletized with glycerol as binder

William A. González, Felix Zimmermann & Juan Fernando Pérez
In this work, the effect of airflow rate and glycerol content of pelletized fallen leaves (FL) on a fixed bed gasification process is studied. FLs were collected in the main campus of the University of Antioquia (Medellin, Colombia). Levels of airflow rate tested were 0.075, 0.150, and 0.225 kg/s/m2; and the glycerol content of pellets evaluated were 0 and 5%wt. When the airflow rate increased, flame front velocity increased up to 51.3%. This behavior was...

Tetrabromidocuprates(II)—synthesis, structure and EPR

André Zabel, Alette Winter, Alexandra Kelling, Uwe Schilde & Peter Strauch
Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several “onium” cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the...

An algorithm of daubechies wavelet transform in the final field when processing speech signals

Dmitry Popov, Artem Gapochkin & Alexey Nekrasov
Development and improvement of a mathematical model for a large-scale analysis based on the Daubechies discrete wavelet transform will be implemented in an algebraic system possessing a property of ring and field suitable for speech signals processing. Modular codes are widely used in many areas of modern information technologies. The use of these non-positional codes can provide high-speed data processing. Therefore, these algebraic systems should be used in the algorithms of digital processing of signals,...

Antimony mining from PET bottles and e-waste plastic fractions

Ayah Alassali, Caterina Picuno, Hanin Samara, Sascha Diedler, Silvia Fiore & Kerstin Kuchta
In this study antimony concentration was analyzed in 30 plastic items (from polyethylene terephthalate (PET) bottles and e-waste) directly by X-ray fluorescence spectroscopy (XRF) spectroscopy. PET samples were digested in a microwave oven with aqua regia. The plastic components deriving from e-waste followed three parallel routes: 1. microwave digestion using different acids (aqua regia, 18 M H2SO4, 12 M HCl and 6 M HCl); 2. conversion into ash (at 600 °C) and then microwave digestion...

Agrochemical plastic packaging waste decontamination for recycling: pilot tests in Italy

Caterina Picuno, Zoe Godosi, Kerstin Kuchta & Pietro Picuno
Agriculture, one of the main economic pillars in Europe, plays a growing important role towards the environmental sustainability of the extra-urban land, in which the agricultural activities may proactively contribute to control and regulate the whole ecological conditions. Modern agriculture currently needs big quantities of agrochemicals, which are necessary for the growth and protection of crops and animals. These agrochemicals are commercially distributed to consumers in many types of containers. The most widely used packaging...

Building-linked location-based Instantaneous services system

Julian Ohrt & Volker Turau

A New Integrated Lab-on-a-Chip System for Fast Dynamic Study of Mammalian Cells under Physiological Conditions in Bioreactor

Janina Stephanie Bahnemann, Negar Rajabi, Grischa Fuge, Oscar Platas Barradas, Jörg Müller, Ralf Pörtner & An-Ping Zeng
For the quantitative analysis of cellular metabolism and its dynamics it is essential to achieve rapid sampling, fast quenching of metabolism and the removal of extracellular metabolites. Common manual sample preparation methods and protocols for cells are time-consuming and often lead to the loss of physiological conditions. In this work, we present a microchip-bioreactor setup which provides an integrated and rapid sample preparation of mammalian cells. The lab-on-a-chip system consists of five connected units that...

RUVIVAL Publication Series Volume 5

Zhuoheng Chen, Rahel Birhanu Kassaye, Ruth Schaldach, Antonio Seoane Dominguez, Tavseef Mairaj Shah & Sumbal Tasawwar
The RUVIVAL Publication Series is a compilation of literature reviews or introductory texts on topics concerned with the revitalisation of rural areas. It 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 http://www.hoou.de. The first paper is an introduction to the global soil status, which in the past decades has continued to deteriorate. Globally, the total...

Towards sustainable development by new town planning : case study of Mazandaran Province of Iran

Ali Zahedi
Das New-Town-Planungskonzept wurde als alternative Lösung zur Regulierung des Stadt-Land-Wachstums in der iranischen Provinz Mazandaran übernommen. Die Forschung wurde in drei Hauptaspekten durchgeführt. Erstens, lokale Entwicklung durch die Gründung von Kleinunternehmen mit Low-Tech-Lösungen. Zweitens, das menschliche Wohlbefinden Beurteilung im Kandelous Dorf durch die Berücksichtigung von Wohnen, Einkommen und Arbeit, Work-Life-Balance, Bildung, Umweltqualität, Gesundheit, bürgerschaftliches Engagement und Governance, persönliche Sicherheit, soziale Zusammenhänge, Glück und Themen der Lebenszufriedenheit, Drittens , das Studiengebiet ist ein guter Ort, um...

Low-pressure micro-mechanical re-adaptation device sustainably and effectively improves locomotor recovery from complete spinal cord injury

Veronica Estrada, Julia Krebbers, Christian Voss, Nicole Brazda, Heinrich Blazyca, Jennifer Illgen, Klaus Seide, Christian Jürgens, Jörg Müller, Rudolf Martini, Hoc Khiem Trieu & Hans Werner Müller
Traumatic spinal cord injuries result in impairment or even complete loss of motor, sensory and autonomic functions. Recovery after complete spinal cord injury is very limited even in animal models receiving elaborate combinatorial treatments. Recently, we described an implantable microsystem (microconnector) for low-pressure re-adaption of severed spinal stumps in rat. Here we investigate the long-term structural and functional outcome following microconnector implantation after complete spinal cord transection. Re-adaptation of spinal stumps supports formation of a...

Mass production of highly active NK cells for cancer immunotherapy in a GMP conform perfusion bioreactor

Katharina Bröker, Evgeny Sinelnikov, Dirk Gustavus, Udo Schumacher, Ralf Pörtner, Hans Hoffmeister, Stefan Lüth & Werner Dammermann
NK cells have emerged as promising candidates for cancer immunotherapy, especially due to their ability to fight circulating tumor cells thereby preventing metastases formation. Hence several studies have been performed to generate and expand highly cytotoxic NK cells ex vivo, e.g., by using specific cytokines to upregulate both their proliferation and surface expression of distinct activating receptors. Apart from an enhanced activity, application of NK cells as immunotherapeutic agent further requires sufficient cell numbers and...

A holistic approach for low cost heliostat fields

Andreas Pfahl, Michael Randt, Florian Meier, Martin Zaschke, Chris Geurts & Michael Buselmeier
The AutoR-project takes a holistic approach to reduce the cost of heliostat fields: Wireless control and energy supply enables to use smaller heliostats which need less steel per mirror area (but usually have high wiring cost). A low cost but high efficient drive system is chosen which reduces energy consumption to a minimum amount and leads to low cost for PV cell and energy storage. The usual boundary layer wind tunnels tests for heliostats are...

Iron oxide-based nanostructured ceramics with tailored magnetic and mechanical properties: Development of mechanically robust, bulk superparamagnetic materials

Diletta Giuntini, Elisa Torresani, Kyle T. Chan, Malte Blankenburg, Lucien Saviot, Büsra Bor, Berta Domènech Garcia, Meir Shachar, Martin Müller, Eugene A. Olevsky, Javier E. Garay & Gerold A. Schneider
Nanostructured iron-oxide based materials with tailored mechanical and magnetic behavior are produced in bulk form. By applying ultra-fast heating routines via spark plasma sintering (SPS) to supercrystalline pellets, materials with an enhanced combination of elastic modulus, hardness and saturation magnetization are achieved. Supercrystallinity-namely the arrangement of the constituent nanoparticles into periodic structures-is achieved through self-assembly of the organically-functionalized iron oxide nanoparticles. The optimization of the following SPS regime allows the control of organics' removal, necking,...

Comparative analysis and biochemical characterization of two endo-β-1,3-glucanases from the thermophilic bacterium fervidobacterium sp.

Christin Burkhardt, Christian Schäfers, Jörg Claren, Georg Schirrmacher & Garabed Antranikian
Laminarinases exhibit potential in a wide range of industrial applications including the production of biofuels and pharmaceuticals. In this study, we present the genetic and biochemical characteristics of FLamA and FLamB, two laminarinases derived from a metagenomic sample from a hot spring in the Azores. Sequence comparison revealed that both genes had high similarities to genes from Fervidobacterium nodosum Rt17-B1. The two proteins showed sequence similarities of 62% to each other and belong to the...

Aufgabenkonzepte für eine bessere Qualität von E-Prüfungen

Dennis Gallaun, Karsten Kruse & Christian Seifert
E-Assessment kann den Prüfungs- und Korrekturaufwand für die Lehrenden drastisch reduzieren. Es sollte aber auch dazu genutzt werden didaktisch anspruchsvolle Aufga-ben zu entwickeln. Im Rahmen von verschiedenen elektronischen Prüfungen in der Mathematik an der Technischen Universität Hamburg schreiben wir adaptive elektroni-sche Aufgaben mit automatischer Korrektur, und auf diesem Poster werden wir Aufga-benkonzepte vorstellen, mit denen sich die Qualität von Prüfungen verbessern lässt. Um insbesondere in großen Gruppen den Trainingsprozess für jede Studierende indivi-duell fair zu...

Mobiles Testcenter für E-Prüfungen

Dennis Gallaun, Karsten Kruse & Christian Seifert
Die Infrastruktur zur Durchführung von elektronischen Prüfungen ist meist stationärer Natur, d.h. sie werden in eigens dafür eingerichteten Räumen auf stationären Geräten durchgeführt. Das Hamburger MINTFIT Projekt [1] beschreitet hier einen anderen Weg und weicht vom Konzept eines stationären Testcenters ab, hin zu einem mobilen. Beim Hamburger MINTFIT Projekt handelt es sich um ein Kooperationsprojekt im Bereich E-Assessment von vier Hamburger Hochschulen und einem Universitätsklinikum, das neben der Erstellung von elektronischen Einstufungstests für das Studium...

Artificial intelligence and digital transformation in supply chain management : innovative approaches for supply chains

This volume contains research contributions by an international group of authors addressing innovative and technology-based approaches for logistics and supply chains. They present business models and investment options for enhanced strategic decision making as well as recent approaches for supply chain analytics and risk management. This volume, edited by Wolfgang Kersten, Thorsten Blecker and Christian Ringle, provides valuable insights into the digitalization of Supply Chain Management and Logistics with regard to: Innovation and Technology Management,...

SmartAirCargoTrailer : autonomous short distance transports in air cargo

Benjamin Bierwirth, Ulrich Schwanecke, Thomas Gietzen, Daniel Andrés Lopéz & Robert Brylka
Purpose: SmartAirCargoTrailers improve short-distance air cargo transports within airport premises. They create real-time-transparency between the partners in the transport chain and thereby reduces waiting times while at the same time increasing equipment utilization. An autonomous truck with swap bodies facilitates these short-distance transports. Methodology: The SmartAirCargoTrailer system consist of an autonomous truck with swap trailers which is controlled by a cloud platform. To allow for real-timetransparency all shipments loaded onto the trailer are detected by...

Algorithm for situation-dependent adaptation of velocity for shuttle based systems

Thomas Kriehn, Franziska Schloz, Robert Schulz & Markus Fittinghoff
Purpose: Shuttle based storage and retrieval systems (SBS/RS) are suitable for applications which require a high throughput. Many times, however, the maximum performance of SBS/RS is not required. For example, when customers initiate a large number of retrieval requests at a specific time, or when a large number of storage requests enter the system at fixed times due to scheduled inbound deliveries. This article presents and discusses an algorithm that is based on closed-loop-control. Methodology:...

Can gamification reduce the shortage of skilled logistics personnel?

Florian Hofbauer & Lisa-Maria Putz
Purpose: The logistics sector faces a worldwide shortage of skilled personnel. Gamification represents a new approach to attract people's interest by applying game elements in a non-game context. In our study, we develop a theoretical framework to improve the image of the logistics sector using gamification for future studies. Methodology: Based on the findings of the literature review, we discuss gamification and its potential to improve the image of the logistics sector. Moreover, the core...

Blockchain adoption at German logistics service providers

Oliver Kühn, Axel Jacob & Michael Schüller
Purpose: The study provides a recent overview of the diffusion of blockchain technology in the logistics industry. It reveals the adoption of blockchain technology at German logistics service providers (LSPs) and their expectations regarding the future relevance of the technology. Based on the TOE Framework adoption supporting and inhibiting factors are identified. Methodology: In a first step, LSPs listed in the “Die Top 100 der Logistik 2016/2017” were contacted and questioned about their blockchain activities....

Smart risk analytics design for proactive early warning

Katharina Diedrich & Katja Klingebiel
Purpose: Automobile manufacturers are highly dependent on supply chain performance which is endangered by risks. They are not yet able to proactively manage these risks, often requiring reactive bottleneck management. A proactive and digitalized early warning method is needed. Methodology: The publication provides methodological-empirical contribution to proactive early warning resulting in a smart risk management approach. The methodological approach is carried out according to the design science research approach. Findings: The developed smart risk management...

Active strain-sensing with a nanoporous-metal hybrid material

Charlotte Kuss
In dieser Arbeit werden die ersten aktiven Dehnungs-Sensorikmessungen mit einen nanoporösen Metall-Hybridmaterial vorgestellt. Die hier hergeleitete thermodynamische Beziehung zwischen elastischen Eigenschaften, sowie Sensorik- und Aktorikparametern weist eine gute Übereinstimmung zwischen Experiment und Theorie auf. Diese Klasse von Materialien verhält sich phänomenologisch wie die der Piezokeramiken, obwohl die zugrundeliegenden Mechanismen völlig verschieden sind.

Simulation-based optimization at container terminals: a literature review

Marvin Kastner, Hannah Pache & Carlos Jahn
Purpose: While simulation-based optimization has been discussed in theory and practically employed at container terminals, the different publications in this field have not yet been presented and compared in a structured manner. This paper gathers the latest developments and examine the similarities and differences of the provided approaches. Furthermore, research gaps are identified. Methodology: The recent literature of simulation-based optimization on container terminals is examined using a mapping review approach. Emphasis is laid on the...

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