Practical trainings, student assistants and theses

Nonlinear characterization of horizontal gas-liquid flows (Id 266)

Student practical training / Bachelor theses / Master theses / Diploma theses / Student Assistant / Compulsory internship

Foto: Nonlinear characterization of horizontal gas-liquid flows ©Copyright: Dr. Philipp WiedemannHorizontal gas-liquid flows occur in a variety of processes in energy and process engineering. According to the type of fluids, operating conditions and geometrical aspects different flow patterns are observed. These can be identified successfully by means of online monitoring systems when using appropriate measurement techniques and data processing algorithms.
Within the frame of an internship further investigations will focus on the predictability of the future development of the flow patterns on the basis of currently measured data. For that purpose, methods for characterizing nonlinear systems will be applied to available data that was recorded with the aid of an imaging technique.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wiedemann, Philipp

Requirements

- studies in mathematics/physics/engineering
- interest in applying sophisticated mathematical methods to engineering problems
- good written and oral communication skills in English and German

Conditions

- start: immediately
- working in a multi-disciplinary team
- remuneration according to HZDR internal regulations

Links:

Online application

Please apply online: english / german

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Experimental investigation of particle remobilisation from wall surfaces with well-defined asperities (Id 265)

Master theses / Diploma theses / Compulsory internship / Volunteer internship

As member of the Helmholtz Association of German Research Centers, the Helmholtz-Zentrum Dresden – Rossendorf (HZDR) employs about 1,200 people. The Center's focus is on interdisciplinary research in the areas energy, health, and matter.

The Institute of Fluid Dynamics of HZDR has a strong focus on the resuspension of micron particles in turbulent flows. It invites applications for a six-month internship to investigate experimentally the particle detachment from wall surfaces in turbulent flows. The position is available immediately. Kindly submit your completed application (including cover letter, CV, diplomas/transcripts, etc.) via our Online-application-system.

Advances in the generation of functional surfaces (i.e. surfaces with well-defined asperities) make it possible to design self-cleaning surfaces. The automotive industry may for instance benefit from such advances. The aim of the project is to study experimentally the detachment of “dust” particles (glass beads with diameters ranging from 10 to 50 µm) on smooth substrates with precisely defined asperities (size of the asperities about 1 µm). The collision of the rolling dust particles with the asperities is expected to boost the resuspension, thereby leading to an enhanced self-cleaning effect of such surfaces.

The tasks of the project will involve:
- Perform a literature survey on the resuspension of micron-particles in turbulent flows
- Design a small wind tunnel to study the particle detachment from wall surfaces with well-defined asperities
- Use of high-speed cameras to visualize the particle detachment in turbulent flows

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Lecrivain, Gregory

Requirements

Interest in fluid dynamics
Studies in natural sciences or engineering
Willingness to conduct experimental work

Conditions

Remuneration is normally offered to our trainees
German lessons are also available free of charge

Online application

Please apply online: english / german

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Energetische Bewertung der CO2-Abtrennung von Syngasturbinen mittels intensiverter Trennapparate (Id 263)

Master theses / Diploma theses

Um die von der europäischen Union anvisierten Klimaziele zu erreichen muss eine deutliche Reduktion der CO2-Emissionen erfolgen. Hierbei ist eine Abtrennung von CO2 bei nicht substituierbaren Quellen wie der Zement und Stahlindustrie notwendig. Weiterhin werden dezentrale Blockheizkraftwerke einen wesentlichen Beitrag zur Lastflexibilität leisten und somit die Versorgungsstabilität (Backbone) für den Fall gewährleisten, dass erneuerbare Energien temporär nicht verfügbar sind. Da mittelfristig ein Betrieb dieser Blockheizkraftwerke mit Erdgas und punktuelle CO2-Quellen nicht zu vermeiden sind, ist ein geeignetes Konzept zur effizienten CO2-Abtrennung erforderlich. Ein Ansatzpunkt ist die Kopplung von Gasturbine und HiGEE-Trennapparaten über einen gemeinsamen Rotor. HiGEE-Apparate bestehen aus rotierenden Packungen, in denen Waschmittel und Rauchgas unter Ausnutzung der Zentrifugalkraft kontaktiert werden.

Im Rahmen der Arbeit ist eine Recherche zu CO2-Punktquellen in Deutschland und Europa durchzuführen und die CO2-Emissionen sind quantitativ und qualitativ einzuordnen. Ein Konzept zur CO2-Abscheidung ist energetisch zu bewerten. Exemplarisch sollen Betriebsdaten (Leistung, Wirkungsgrad, Abgaszusammensetzung und -temperatur) eines Blockheizkraftwerkes angenommen werden. Daten zur CO2-Abtrennung mittels HiGEE-Apparate sind aus der Literatur zu extrahieren.

Folgende Teilarbeiten sind durchzuführen:

- Recherche zu CO2-Punktquellen in Deutschland und Europa
- Recherche/Analyse der Überschussstromproduktion in Deutschland anhand einer Beispielregion
- Ausstellen der Wärme- und Stoffbilanzen und möglicher energetischer Verschaltungen (Wärmerückgewinnung)
- Abschätzungen erforderlicher HiGEE-Apparategrößen
- Bestimmung des Turbinenwirkungsgrades unter Berücksichtigung des Desportionsprozesses

Department: Experimental Thermal Fluid Dynamics

Contact: Fogel, Stefan, Unger, Sebastian

Requirements

Student (m/w/d) im Bereich Energietechnik, Chemie- oder Elektroingenieurwesen, Verfahrenstechnik oder ähnlicher fachlicher Ausrichtung.
Kenntnisse in Aspen Plus, ChemCAD oder ähnlichen Programmen sowie gute Sprachkenntnisse in Englisch.

Conditions

Mindestdauer: 6 Monate; ab sofort durchführbar.

Online application

Please apply online: english / german

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Gas phase simulation of pressure wave in a gas-injection pipe (Id 259)

Student practical training / Bachelor theses / Master theses / Diploma theses

Foto: Bubble Formation ©Copyright: Ehsan Mohseni, Ehsan MohseniIn two-phase flows, the interface at which the phases are in contact to one another is of high importance. One way to manipulate the dynamic of this interface is to modulate the pressure field within the gas phase. Accordingly, it is intended to study the influence of pressure modulation in a gas pipe with multiple openings. In this content, the system characteristics should be defined and the effect of individual parameters, which influence the temporal change of the pressure field at the openings are going to be studied. These parameters include frequency and amplitude of excitations, pressure fluctuation, geometry of the pipe and the openings, gas flow rate, etc. To peruse this idea, it is intended to simulate the gas pressure field in the pipe and under the opening using COMSOL Multiphysics.

Task Spectrum:
• Establishment of a profound scientific knowledge in the field of acoustics and wave propagation
• Literature review on interacting two phase flows and pressure waves
• Establishing the simulation strategy
• Model the geometry, flow domain, establishing the initial and boundary condition
• Performing the simulation with various geometries and post processing the result
• Generate scientific documentation

Department: Experimental Thermal Fluid Dynamics

Contact: Mohseni, Ehsan, Dr. Reinecke, Sebastian

Requirements

• Studies in mechanical, chemical, process engineering, and similar engineering courses
• Experience in simulation with COMSOL Multiphysics
• Optionally but not necessarily experience with acoustic module of COMSOL Multiphysics
• Independence, self-responsible working methods

Conditions

Duration: 6 Months

Online application

Please apply online: english / german

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Modelling of bubble formation on submillimeter submerged orifice (Id 258)

Student practical training / Bachelor theses / Master theses / Diploma theses

Foto: Bubble Formation ©Copyright: Ehsan Mohseni, Ehsan MohseniBubbles are an inevitable part of almost all chemical and process engineering processes as long as heat and mass transfer or particle separation are concerned. Formation of bubbles from a submerged orifice is a typical fluid dynamic phenomenon, which incorporates the influence of different characteristics of both gas and liquid phases. Although posing as a simple problem in the first sight, the formation process varies dramatically by changing influential parameters such as diameter and geometry of orifice, volume of gas reservoir under the orifice, surface tension, density and viscosity of both continuous and dispersed phases, etc. Among these parameters, the effect of the volume of the gas reservoir under the orifice is highly influential. Within an ongoing investigation, we are experimentally studying the effect of this parameter on the dynamics of bubbles generated at orifices smaller than 1 mm. A sub task of this investigation associates the findings of the experimental studies into a mechanistic model, which is designed to estimate the final bubble size.

Task Spectrum:
• Establishment of a profound scientific knowledge into the phenomena of bubble formation and detachment
• Concept development and establishing solution strategy for the bubble volume
• Implementing the solutions into MATLAB
• Compare and adopting the model based on the experimental results
• Generate scientific documentation

Department: Experimental Thermal Fluid Dynamics

Contact: Mohseni, Ehsan, Dr. Reinecke, Sebastian

Requirements

• Studies in mechanical, chemical, process engineering, and similar engineering courses
• Experience in data analysis and programming with MATLAB
• Independence, self-responsible working methods

Conditions

Duration: 6 Months

Online application

Please apply online: english / german

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6-month internship on the experimental investigation of granular mixing (Id 255)

Student practical training / Bachelor theses / Master theses / Diploma theses / Compulsory internship / Volunteer internship

Background:
Granular mixing is an important industrial process. In the pharmaceutical industry for instance, the powder that is pressed to make tablets is produced by mixing precise quantities of active substances and excipients in granular state. The mixing needs to be done in such a way that the final powder has a homogeneous composition. Tablets may also need to be coated in a pan coater. Granular mixing also plays a crucial role there, as it greatly affects the thickness of the coating. Granular mixing is also often coupled with heat exchanging and solid-gas or solid-solid reactions, as is the case of rotary kilns in the cement, ceramics and metallurgical industries. The quality of the mixing is then a crucial factor to the efficiency of the overall process.

Objectives:
The objective of the work is to experimentally study the mixing process of two different types of granular particles inside a rotating drum under various operating conditions. More specifically, the mixing process is to be captured with a high-speed camera. The videos are then to be post-processed in order to extract characteristics of the particle velocity fields and mixing efficiency. The mixing facility is already available.

Tasks:
• Literature survey
• Mixing experiments under various operating conditions
• Post-processing of the results with MATLAB

Department: Experimental Thermal Fluid Dynamics

Contact: Papapetrou, Theodoros Nestor

Requirements

• Student of natural sciences or engineering
• Willingness to conduct experimental work

Conditions

Duration: 6 months

Online application

Please apply online: english / german

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Investigation of the flow behavior of fluidized particles by means of coupled CFD-DEM simulations (Id 253)

Master theses / Diploma theses / Compulsory internship

Foto: CFD-DEM fluidized bed ©Copyright: Dr. Philipp WiedemannFluidized beds are widely applied in process plants of pharmaceutical, food and chemical industries. Due to the complex flow structure optimization of such devices and process control is usually supported by simulations. However, since it is not feasible to resolve all spatial and temporal scales within a single simulation environment, large-scale simulations require reliable sub-models in order to account for small-scale phenomena correctly.
Therefore, the macroscopic flow properties of fluidized particles will be investigated by means of CFD-DEM simulations within the frame of an internship. Research will focus on the influence of different particle size distributions. The results shall lead to enhanced insight into the complex gas-solids-interaction of fluidized beds and will be incorporated into future developments.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wiedemann, Philipp

Requirements

• studies in chemical/mechanical/process engineering
• interest in multiphase flow phenomena
• good written and oral communication skills in English and German
• knowledge in computational fluid dynamics is beneficial

Conditions

• start: immediately
• scope of work: up to 6 months (according to study regulations)

Online application

Please apply online: english / german

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Design of a flexible pressure swing adsorption (PSA) process (Id 251)

Bachelor theses / Master theses / Diploma theses

As part of the Energiewende, the Institute for Fluid Dynamics at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is adapting energy intensive processes for the production of chemicals to be supplied only with electricity from renewable resources.
Air separation is the source of two diatomic molecules key to a number of industrial processes, O2, and N2. Pressure Swing Adsorption (PSA) is a process capable of producing N2 for erratic use patterns, and thus, a possible candidate for flexible operation.
The objective of the thesis is to model in Aspen Plus/Aspen Adsorption a PSA process capable of operating with an intermittent energy supply, whether from renewable resources or from low priced electricity.

Tasks:

• Collect data on air separationunits using renewable energies and other flexible energy sources and its simulation.
• Design a dynamic PSA process.
• Adapt it for its operation with an intermittent energy supply.
• Assess the compatibility of the process with flexible water electrolysis, and ammonia synthesis (Haber-Bosch process).
• Evaluate its O2 generation potential.

Department: Experimental Thermal Fluid Dynamics

Requirements

• Student of Chemical or Process Engineering, Energy Technology (Renewable Energy Systems), or similar.
• Experience with Aspen Plus, ChemCAD or similar
• High level of English.

Conditions

• 4-6 Months
• Starting as soon as possible

Online application

Please apply online: english / german

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Programmierung und Implementierung einer Ethernet-Schnittstelle für einen FPGA (Id 246)

Student practical training / Student Assistant / Compulsory internship / Volunteer internship

Zur Realisierung eines kontinuierlichen Messdatentransfers zu einem PC soll ein FPGA zum Einsatz kommen, der hierfür die kommerzielle Datenschnittstellen Ethernet (GbE) nutzen/realisieren soll. Vor dem integralen Einsatz des Chips im vorgesehenen Messsystem soll die benötigte Logik per Evaluierungsboard [1] im FPGA implementiert und die Performance über einen Datenempfangskernel (C++) eruiert werden.

[1] https://www.sinelec-tech.com/website/Expansion-modules.php?urlstring=eNortjI0sVIqKMpPKU0uic9MsTU0MlayBlwwUXcGzA

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Bieberle, André, Windisch, Dominic, Dr. Knodel, Oliver

Requirements

• Studium im naturwissenschaftlichen oder ingenieurswissenschaftlichen Bereich
• Erfahrung mit der Programmiersprache C++
• Optional: Erfahrung im Umgang von FPGAs oder CPLDs
• Optional: Erfahrung mit der Entwicklungsplattform Vivado oder ISE (Xilinx)

Conditions

• 4-6 Monate
• sofort durchführbar

Online application

Please apply online: english / german

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Beiträge zu innovativen Konzepten für die ultraschnelle Röntgencomputertomografie (Id 211)

Student practical training / Master theses / Diploma theses

Die im Institut für Fluiddynamik am HZDR entwickelte Ultraschnelle Röntgencomputertomografie wird bei der Beforschung von Strömungsvorgängen auf einer Vielzahl von Themengebieten als berührungsloses, bildgebendes Messverfahren genutzt. Dabei werden aus Projektionsdatensätzen 2D-Schnittbildsequenzen mit hoher räumlicher und sehr hoher zeitlicher Auflösung generiert. In den letzten Jahren wurden die bestehenden ROFEX-Scanner stetig verbessert. Gleichwohl besteht ein hohes Entwicklungspotenzial im Bereich der Röntgenstrahlungserzeugung.
Im Rahmen dieser Arbeit sollen Schlüsselexperimente auf dem Gebiet der schnell gepulsten Röntgenstrahlungserzeugung geplant und durchgeführt werden.

Teilaufgaben:
• Literaturstudium zu gesteuerter bzw. provozierter Feldemission
• Grundsätzliche Berechnungen; evtl. Simulationen
• Aufbau eines Demonstrators und Experimente zur getakteten Erzeugung von Röntgenstrahlung

Infos zu ROFEX-Scanner: https://www.hzdr.de/db/Cms?pOid=30242&pNid=0

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Barthel, Frank

Requirements

• Studium der Elektrotechnik/Physik/Maschinenbau
• Strukturierte, selbstständige Arbeitsweise
• Technische Kreativität und Gestaltungswille
• Konstruktionsfähigkeiten

Online application

Please apply online: english / german

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Smart actuation system for flow following µAUV particles for industrial process environments (Id 175)

Master theses / Diploma theses / Compulsory internship

Foto: flow following sensor particle ©Copyright: Dr. Sebastian ReineckeSmart flow following sensor particles are used for acquisition of spatially distributed process parameters in industrial processes, such as biogas digesters, waste water treatment basins or bioreactors. The aim of the work is the development of an actuator concept for sensor µAUV-particles for the automatic adjustment of buoyancy (buoyancy) and for buoyancy maneuvers under the condition of small size, minimum energy consumption and high reliability. For this, alternative physical and chemical mechanisms should be considered based on the existing electromechanical solution. There are suitable variants to implement and test. Furthermore, the development of sensor intelligence for the actuators in the sensor particles is an essential part of the task. The developed concepts have to be validated experimentally.

We cordially invite you to an on-site conversation to introduce the topic and to agree on further details. Do not hesitate to contact us, because the way is worth it for you.

What can you expect:

In our department, we offer you an attractive work environment to expand your personal and professional skills. The insight into the diverse R&D projects of the department in the areas of sensor and measuring technology as well as energy and process engineering (among others) and the excellent technical equipment of the laboratories offer optimal conditions for this. The possibility of close contact with competent experienced colleagues plays a central role. As part of student work, we have pursued the approach of structured supervision and associated constructive feedback. This includes regular meetings with your supervisor and intermediate presentations in the form of informal "workshop reports" in the extended audience of interested individuals of the department in order to optimally support you in the successful completion of your project. Furthermore, we are open to support outstanding candidates in their continuing academic qualification, such as in doctoral scholarships or in current or upcoming R&D projects.

Subject-related task spectrum:

• Establishment of the scientific and technical principles of mechanical, physical and chemical principles of action for embedded, actuating components
• Concept development for actuators for taring of sensor particles
• Development of sensor intelligence for situation-dependent, automatic buoyancy, for buoyancy maneuvers and for recovery
• Selection, purchase/ composition and comparison of solution variants
• Minimization of size and energy consumption
• Increased reliability when used in particle-loaded biological substrates
• Development of firmware taking into account existing function routines based on an embedded system with 32-bit data structure (e.g. STM32)
• Conception and realization of suitable test scenarios
• Characterization and comparison of implemented variants with regard to accuracy of taring and reliability in long-term use

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Reinecke, Sebastian

Requirements

• Studies in electrical engineering, mechatronics, mechanical engineering and similar engineering courses
• Experience in design and (micro) actuator systems
• Experience in programming microcontrollers for embedded systems (e.g. STM32)
• Experience in control electronics for microdrives and board design for embedded systems
• Fundamentals of (micro) actuator systems, movement of rigid bodies, measurement uncertainties, digital signal processing
• Data analysis optionally in Matlab, Octave or C / C ++
• Independent, self-responsible working method

Links:

Online application

Please apply online: english / german

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Bestimmung von Geschwindigkeitsfeldern aus tomographischen Bilddaten mittels Kreuzkorrelation (Id 164)

Bachelor theses / Master theses / Diploma theses

Foto: ROFEX CAD ©Copyright: Dr. Frank BarthelAm Institut für Fluiddynamik am Helmholtz-Zentrum Dresden-Rossendorf sind zahlreiche Messverfahren für die Untersuchung von Mehrphasenströmungen entwickelt worden. Eines davon ist die ultraschnelle Elektronenstrahl-Röntgen-Computertomographie, welche mit Aufnahmeraten von bis zu 8000 Bildern pro Sekunde eine dedizierte Aufklärung von Strömungsstrukturen erlaubt. Aufgrund der quasi simultanen Aufnahme von Bilddaten aus zwei Messebenen ergibt sich zudem die Möglichkeit, axiale Geschwindigkeiten zu bestimmen, wofür üblicherweise Kreuzkorrelationsverfahren verwendet werden. Im Rahmen dieser Arbeit sollen die Möglichkeiten dieser Methodik in Hinblick auf die Bestimmung von Geschwindigkeitsfeldern in verschiedenen Strömungsszenarienn analysiert werden.

Folgende Teilaufgaben sind zu lösen:
• Studie zu verschiedenen Varianten der Kreuzkorrelation
• Simulation verschiedener Szenarien und Bewertung der Genauigkeit
• Übertragung der Ergebnisse auf reale Messungen

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Bieberle, Martina

Requirements

• Studium der Informatik, Mathematik oder einer Ingenieurwissenschaft
• Interesse an Messverfahren und Datenanalyse
• Selbständiges Arbeiten

Conditions

Bearbeitungszeit 4 bis 6 Monate

Links:

Online application

Please apply online: english / german

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Untersuchungen zur Steigerung der Energieeffizienz von Belüftungselementen für die Anwendung in der biologischen Abwasserreinigung (Id 154)

Student practical training / Bachelor theses / Master theses / Diploma theses / Student Assistant

Foto: SEBAK setup and aerators ©Copyright: Robert Herrmann-HeberDie biologische Abwasserbehandlung leistet einen wesentlichen Beitrag zum Erhalt der Gewässerqualität. Im kommunalen Bereich entfällt ein großer Anteil des Gesamtenergiebedarfs auf die Kläranlagen. In diesen Anlagen wird oft mehr als 50 % der elektrischen Energie für den Eintrag von Luft in Belebungsbecken benötigt, in denen Mikroorganismen die im Abwasser enthaltenen Nährstoffe unter Verbrauch von Sauerstoff zersetzen.
Nach aktuellem Stand der Technik wird die Luft durch Belüftungselemente wie Membran- oder Keramikbelüfter eingetragen. Ein Teil der für den Lufteintrag benötigten Energie wird entweder für die Dehnung der schlitzförmigen Öffnungen der Membranen oder zur Überwindung des Strömungswiderstandes in der Keramikwand aufgewendet.
Neue Konzepte sollen diesen Energiebedarf reduzieren und für einen optimierten Sauerstoffeintrag in das Belebungsbecken sorgen.

Department: Experimental Thermal Fluid Dynamics

Contact: Herrmann-Heber, Robert

Requirements

• Studium im Bereich Verfahrenstechnik, Chemie-Ingenieurwesen und ähnlichen Ingenieurstudiengängen
• Freude am experimentellen Arbeiten

Conditions

• 4-6 Monate
• Ab September/Oktober

Online application

Please apply online: english / german

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Untersuchung des Einflusses von Regularisierungsmethoden auf Bildrekonstruktionsalgorithmen (Id 57)

Student practical training / Bachelor theses / Master theses / Diploma theses

Bei der tomographische Bildrekonstruktion muss ein diskretes inverses Problem gelöst werden, wofür algebraische Methoden wie zum Beispiel ART und CG-Verfahren verwendet werden können. Dabei spielt die Regularisierung, die den Einfluss von Diskretisierungsfehler und Messdatenrauschen auf die Lösung beschränkt, eine entscheidende Rolle. Deren Einfluss auf die Bildrekonstruktion von Röntgen- und Gamma-CT-Messdaten soll untersucht werden. Dazu sind folgende Teilaufgaben zu lösen:
• Implementierung verschiedener Regularisierungsmethoden
• Anwendung der Programme auf Messdaten
• Parameterstudien um die Regularisierungsmethoden für die Messdatensätze zu optimieren.

Department: Experimental Thermal Fluid Dynamics

Contact: Wagner, Michael, Dr. Bieberle, Martina

Requirements

• Programmierkenntnisse in MATLAB
• Grundkenntnisse zur numerischen Behandlung linearer Gleichungssysteme

Links:

Online application

Please apply online: english / german

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