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Design and Built of an Online Sensor for Thermo Physical Properties of Water

Student practical training / Bachelor theses / Master theses / Diploma theses / Student Assistant / Holiday job / compulsory internship / volunteer internship / Research Assistant

To improve large scale process cooling systems (300kW and 1MW) an online sensor for the thermophysical properties of the coolant is needed to improve the stability of outflow temperature. Here the fluid parameters influence the precision of the power balance at the heat exchanger. The remaining misfit is compensated with a classic PID-controller. A precise knowledge of coolants properties would decrease the fraction of PID and increase the validity of set point calculation. The task would be to develop the present design further to an integrated prototype and to validate the measurement principles (direct measurement, transient hot wire, 3Omega).

The complexity of the problem will be adjusted to the abilities of the student!

Department: Magnetohydrodynamics

Contact: Dr. Seilmayer, Martin

Requirements

• subscription in to electronics, physics, process engineering or similar
• programming languages C/C++, R, Phyton
• experience in DIY soldering, schematic and PCB layouting

Conditions

• Einarbeiten in Messverfahren zu thermophysikalischen Eigenschaften von Fluiden (3\omega-Methode, Temperaturfeldmessung, )

• Entwicklung und Konstruktion eines Sensors zur hydraulischen Integration in die bestehenden Anlagen

• Schaltungsentwicklung der Messtechnik

• Microcontroller-Programmierung

• Validieren des Messverfahrens

Online application

Please apply online: english / german

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Experimental investigation of particle mixing using ultrafast X-ray computed tomography

Master theses / Diploma theses / compulsory internship

Foto: ROFEX CAD ©Copyright: Dr. Frank BarthelBackground:
The Institute of Fluid Dynamics of the German research centre Helmholtz-Zentrum Dresden-Rossendorf has been developing many measurement devices to investigate multiphase flows. One of which is the patented ultrafast electron beam X-ray computed tomography system. With a frequency of up to 8,000 frames per second, a corresponding spatial resolution of about 1 mm and the ability to penetrate opaque walls, the device overcomes many restrictions of other conventional measurement techniques. Whereas the tomography system has so far mostly been applied to the investigation of gas-liquid flows, its range of application has recently been extended to particle flows. Within the internship, this high-speed imaging technique should be qualified for observing the mixing of two particle species, in order to find application in various industrial areas.

Tasks:
• Literature survey on particle mixing and associated applications
• Selection of suitable particles
• Construction of a small mixing facility for research purposes
• Performing tomography measurements
• Quantifying of imaging results

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Bieberle, Martina, Dr. Lecrivain, Gregory

Requirements

• Studies in engineering sciences
• Interest in fluid mechanics and imaging techniques
• High level of autonomy
• Enthusiasm for experimental work

Conditions

Duration: 6 Months
Start: any time from now

Links:

Online application

Please apply online: english / german

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Experimental measurement on the bubble generation by flexible membrane diffusers

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

Foto: Dynamic Bubbling Regime ©Copyright: Ehsan MohseniIn Germany, wastewater is treated in 10000 plants, which use 4,400 GWh of energy per year. From this big figure, only the aeration process in activated sludge basins consumes up to 50%. Aerators with flexible membranes are currently state of the art. However, the aeration process suffers from some limitations such as large bubble size, high-pressure drop of the diffusers, and inadequate mixing. Initial bubble size in gas dispersion is of great importance since it determines the ascent and coalescence rate, macro mixing by turbulence, and oxygen transfer from the bubble to the fluid phase. Although the initial bubble size generated by membrane diffusers is reported in few publications, there is a lack of information on the actual bubble size distribution produced by this type of aerators. To investigate on this issue, high precision optical measurement techniques, such as fluidic sensor microscope or videometery are known to be versatile approaches. Hence, the description of the offered task is as follow:
- Acquiring knowledge in the following areas: activated sludge process, optical measurement techniques, mass transfer in two phase flows
- Preparation of the experimental setup
- Conducting the experiment using high-resolution optical measurement techniques.
- Post processing and evaluating the data
- Writing and presenting the results

Department: Experimental Thermal Fluid Dynamics

Contact: Mohseni, Ehsan

Requirements

• Study programs in the fields of process engineering, chemical engineering, mechanical engineering and related degree programs
• Knowledge in the following areas is advantageous: oxygen mass transfer, biological wastewater treatment, optical measurement techniques.
• Enthusiasm for experimental work
• Data analysis in Matlab
• Structured and independent working

Conditions

The candidate can start from September 2017. The duration of the project can be up to 6 months.

Online application

Please apply online: english / german

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Untersuchung der Fluiddynamik von Zweiphasenströmungen in Kolonnen mit Anstaupackungen

Bachelor theses / Master theses / Diploma theses / compulsory internship

In thermischen Trennapparaten, z.B. Rektifikations- oder Absorptionskolonnen, hat die Fluiddynamik der beteiligten Phasen einen entscheidenden Einfluss auf die Effizienz der Stofftrennung. Eine Möglichkeit, den Kontakt zwischen Gas- und Flüssigkeitsphase zu intensivieren und damit den Stoffübergang zu verbessern, bieten Anstaupackungen. Sie bestehen aus Packungslagen zweier geometrischer Oberflächen, welche abwechselnd axial angeordnet werden. Durch die Kombination unterschiedlicher Packungen entstehen verschiedene Strömungsmuster (Blasenströmung, Sprudelschicht, Filmströmung), welche mittels der ultraschnellen Röntgentomografie am HZDR zeitlich und örtlich hochaufgelöst erfasst werden können.

Aus den tomografischen Bilddaten sollen im Rahmen einer studentischen Arbeit wichtige fluiddynamische Parameter wie die Phasengrenzfläche extrahiert werden. Dazu sind geeignete Algorithmen zu entwickeln und in MATLAB® zu implementieren.

Department: Experimental Thermal Fluid Dynamics

Contact: Sohr, Johanna, Dr. Bieberle, Martina

Requirements

• mathematisch-naturwissenschaftliches oder ingenieurwissenschaftliches Studium
• Programmierkenntnisse in MATLAB® und Vorkenntnisse in der Bilddatenverarbeitung sind hilfreich

Conditions

Beginn: ab sofort
Bearbeitungszeit: 4-6 Monate

Links:

Online application

Please apply online: english / german

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PVD synthesis and characterization of thin metal films for metal- induced crystallization of amorphous carbon

Bachelor theses / Master theses / Diploma theses

Foto: carbon_lattice ©Copyright: Daniel JankeThe Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is member of the Helmholtz Association of German Research Centres. HZDR pursues interdisciplinary research in the fields of Health, Energy, and Matter and consists of eight institutes. Our Institute, the Institute of Ion Beam Physics and Materials Research has an internationally recognized long term expertise in ion-solid interactions in the contexts of material synthesis, modification or analysis as well as in solid state physics. The research in our group is focused on the processing-structure relationship of thin films and nanostructures grown by PVD methods.

Metal-induced crystallization with and without layer exchange (MIC w/o LE) is a method to decrease the crystallization temperature of amorphous group 14 elements (G14E) by up to several hundred degrees. While MIC w/o LE has been widely studied for Si and Ge in contact with catalytic metals, there exist only a few studies for the crystallization of amorphous carbon (a-C).

Due to its small lattice mismatch with the basal plane of graphite and high diffusivity of C atoms, Ni is a suitable catalyst for the growth of graphene and crystalline graphitic nanostructures. During the annealing of an a-C/Ni layer stack covalent bonds between the carbon atoms at the catalyst interface are weakened. Liberated carbon atoms can move along the interface and diffuse along the grain boundaries into the Ni layer, towards the catalyst surface, where nucleation and grain growth of graphenic crystallites occur. This technique can be used for the low-temperature graphene synthesis. It is demonstrated that the structure and the crystallite size
of the metallic catalyst layer has a strong influence on the crystallite size and the quality of the graphenic film.

Department: Nanocomposite Materials

Contact: Janke, Daniel

Conditions

The applicant will contribute to the improvement and the characterization of the structure and quality of metallic films. He or she will gain hands-on experience in operating physical vapour deposition (PVD) set ups – as magnetron sputtering (DCMS), high power impulse magnetron sputtering (HiPIMS) and ion beam sputtering (IBS) - for thin film deposition. Furthermore the applicant will be involved in a detailed characterization and evaluation of the deposited films.

Links:

Online application

Please apply online: english / german

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Experimentelle Untersuchungen an einer Blasensäule zur Erweiterung numerischer Zweiphasensimulationen

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

Numerische Strömungssimulationen (CFD) bieten in zunehmendem Maße eine Alternative zur experimentellen Optimierung und Verbesserung sowohl bestehender als auch neuartiger industrieller Prozesse oder Produkte, wofür ansonsten kostspielige und zeitaufwendige Versuchs- und Pilotanlagen verwendet werden. Während die Simulation einphasiger Strömungen stabile und
zuverlässige Vorhersagen erlaubt, sind aufgrund der Komplexität und der Vielzahl an zusätzlichen Wechselwirkungen solche numerischen Untersuchungen für mehrphasige Strömungen bisher nur für ausgewählte Fälle validiert und sinnvoll.

Um die Anwendbarkeit numerischer Mehrphasensimulationen zu erweitern, werden am Institut für Fluiddynamik des Helmholtz-Zentrums Dresden-Rossendorf videometrische Untersuchungen in Blasensäulen durchgeführt, um Phasenwechselwirkungsphänomene quantitativ zu erfassen und besser zu verstehen. Für die Durchführung und Analyse dieser
Experimente an einem bestehenden Versuchsstand werden Studentinnen und Studenten der Studienrichtungen Verfahrenstechnik, Maschinenbau o.ä. gesucht. Die Arbeiten werden in einer Gruppe mit intensiver Betreuung am HZDR angefertigt.

Department: Computational Fluid Dynamics

Contact: Heßenkemper, Hendrik

Requirements

• Begonnenes Studium der Verfahrenstechnik, Maschinenbau o.ä.
• Interesse am experimentellen Arbeiten
• Gute englisch Sprachkenntnisse
• Programmiererfahrungen (z.B. Matlab) sind von Vorteil

Conditions

• Arbeitsbeginn ab sofort
• Vergütung der Arbeit
• Bearbeitungszeit min. 3 Monate

Online application

Please apply online: english / german

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Modellierung und Simulation eines tubularen Hochtemperaturelektrolyseurs zur Wasserstoffproduktion

Bachelor theses / Master theses / Diploma theses

Das Institut für Fluiddynamik des Helmholtz-Zentrums Dresden-Rossendorf (HZDR) beschäftigt sich unter anderem mit Fragen der Modellbildung und Simulation von Stoff- und Wärmetransportvorgängen in verfahrenstechnischen Apparaten.

Im Rahmen eines Forschungsprojektes zur Entwicklung eines tubularen Hochtemperatur-Dampfelektrolyseurs mit integrierter Kohlenwasserstoffsynthese soll mit Hilfe kommerzieller Softwarelösungen (COMSOL, MATLAB, usw.) das stationäre und dynamische Betriebsverhalten einer SOEC (Solid Oxide Electrolyzer Cell) charakterisiert werden. Dabei sind die Einflüsse verschiedener Parameter, wie z.B. der Zellgeometrie, Materialeigenschaften, Betriebstemperatur und Gasdurchsatzraten auf das Betriebsverhalten der Zelle zu untersuchen. Auf Basis dieser Simulationen soll ein Konzept zur Prozesssteuerung und -instrumentierung entwickelt werden.

Mögliche Aufgaben:

• Erstellung des zweidimensionalen Geometriemodells eines tubularen Dampfelektrolyseurs mit Hilfe der Software COMSOL Multiphysics
• Modellierung und stationäre Simulation des Stoff- und Wärmetransportes innerhalb des Elektrolyseurs
• Erstellung eines dynamischen Modells eines kombinierten Elektrolyse-Syntheseapparates mit Hilfe der Software MATLAB Simulink
• Durchführung einer Sensitivitätsanalyse hinsichtlich der grundlegenden Betriebsparameter des Elektrolyseurs
• Auswahl geeigneter Analysetechnik zur Prozesscharakterisierung und Identifizierung relevanter Messstellen auf Basis der durchgeführten Simulationen

Department: Experimental Thermal Fluid Dynamics

Contact: Fogel, Stefan

Requirements

• Student(in) der Studiengänge Chemieingenieurwesen, Verfahrenstechnik, Energietechnik, Maschinenbau o. ähnlicher Ausrichtung
• Sorgfältige und selbstständige Arbeitsweise
• Freude an der wissenschaftlichen Arbeit
• Erste Erfahrungen mit den Programmen MATLAB und COMSOL Multiphysics von Vorteil

Conditions

Beginn: ab sofort
Bearbeitungszeit: 4-6 Monate

Online application

Please apply online: english / german

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Phasengrenzflächenextraktion aus Datensätzen der ultraschnellen Röntgen-Computertomographie

Master theses / Diploma theses

Foto: ROFEX CAD ©Copyright: Dr. Frank BarthelAm Helmholtz-Zentrum Dresden-Rossendorf wurde ein ultraschnelles Röntgen-Computertomographie-System (ROFEX) entwickelt, mit dessen Hilfe dynamische Prozesse mit Bildraten von bis zu 8000 s-1 abgebildet werden können. In erster Linie werden damit Untersuchungen an mehrphasigen Strömungen durchgeführt. Ein wichtiger Parameter zu deren Charakterisierung ist die Phasengrenzflächendichte. Aktuell wird diese in einem zweistufigen Prozess bestimmt: zunächst werden die Phasen segmentiert und anschließend wird aus den binären Daten die Oberfläche extrahiert. Alternativ dazu sollen in dieser Arbeit Methoden entwickelt bzw. untersucht werden, welche die Phasengrenzfläche direkt aus den ursprünglich rekonstruierten Bildern bestimmen.

Folgende Teilaufgaben sind zu bearbeiten:
• Literaturrecherche zu vorhandenen Methoden
• Implementierung ausgewählter Algorithmen
• Bewertung der Genauigkeit anhand simulierter und realer CT-Daten

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Bieberle, Martina, Wagner, Michael

Requirements

• Studium der Informatik, Mathematik oder einer Ingenieurwissenschaft
• Programmierkenntnisse in MATLAB
• Vorkenntnisse in Bilddatenverarbeitung sind hilfreich

Conditions

Beginn: ab sofort
Bearbeitungszeit: 4-6 Monate

Links:

Online application

Please apply online: english / german

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A correlation of critical void fraction on/near the wall under the boiling crisis (CHF)

Student practical training / Master theses / Diploma theses / Student Assistant / compulsory internship

Nucleation boiling is commonly known as a most efficient way of transferring heat into a liquid, as it combines a large uptake of latent heat by the steam bubbles, convective transfer via bubble motion and a most effective mixing of the thermal boundary layers. However, when the heat flux becomes higher and reaches a critical value (CHF), parts of the heater surface become irreversibly covered by vapor and nucleation boiling turns into film boiling. In cases of power controlled heating this can potentially lead to a meltdown of the heater structure. Understanding and predicting the complex phenomena involved in the CHF is necessary for the efficient operation, safety and development of industrial applications like boiler, nuclear reactor, electronic/microchips system. However even with decades’ heavy investigations, the mechanism of forming CHF especially how the CHF is initiated from nucleation is still without a consensus explanation.
Recently a model of near critical heat flux (CHF-) is raised in our group, that is, the moment, when CHF is initiated, is inferred. This model gives to our opinion both a definite explanation on how CHF is initiated and secondly a quantitative value for the onset of CHF, which has been validated with a number of test cases from literature. Computational fluid dynamics (CFD) is an attractive way to support engineering design by 3D flow simulation in the future. It would be beneficial, if occurrence of CHF could be simulated with CFD codes. In last years an extended RPI model was developed and tested by ANSYS and HZDR CFD group together which requires the critical void fraction as a criterion. In the preliminary test, this value is set to 80% but which is confirmed should be case dependent.
The main tasks for this work are:
1. Simulate the multiphase flow in subcooled boiling process with standard RPI model where the CHF value calculated by CHF- model is considered as a input boundary condition.
2. Capturing the critical void fraction from the simulations.
3. Processing and analysis the captured results to generate an empirical correlations using MATLAB.
4. Applying the correlations to predict the boiling crisis with extended RPI model.

Department: Computational Fluid Dynamics

Contact: Dr. Ding, Wei

Requirements

1. Study of mechanical engineering, process engineering or similar
2. Knowledge of CFD
3. Basic knowledge of heat transfer
4. Knowledge of program/script language (e.g. MATLAB)

Conditions

Duration: >= 3 months
Begin: from now on

Online application

Please apply online: english / german

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Characterization of the stability of molten salt mixtures in liquid metal batteries by ion chromatography

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

Foto: Experimental Liquid Metal Battery ©Copyright: Flüssigmetallbatterie Abteilung MagnetohydrodynamikLiquid Metal Batteries feature molten salts as electrolytes (at temperatures between 200 °C and 600 °C).
For the long-term operation of the batteries, stability of the molten salt mixture in contact with the anode has to be ensured.
The task is to measure the long-term change in constituents of molten salt mixtures. Ion chromatography is the favored method. For this measurement technique, the following steps shall be evaluated and demonstrated at certain molten salt mixtures: sample preparation, calibration of equipment, measurement and analysis.
This task can be done as part of a practical training or as a final thesis.

Department: Magnetohydrodynamics

Contact: Dr. Nimtz, Michael, Landgraf, Steffen

Requirements

Study of chemistry, chemical engineering, process technology or similar
Optional: first experiences in scientific programming (Python, MATLAB or similar)

Conditions

Start: immediately
Duration: 4-6 months

Links:

Online application

Please apply online: english / german

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Investigating the effects of surface roughness on the microlayer evaporation of nucleated bubbles

Student practical training / Master theses

Evaporation of microlayer is one of main contributions to the bubble growth. The microlayer is a micro meter scale thin liquid layer underneath a nucleated bubble over heated surface. Heat transfer surface characteristics play a crucial role in the formation and the vaporization of this layer. The effects of surface characteristics, especially the roughness effects on the microlayer thickness did not receive that much research interest. The present study aims to predict the surface roughness effects on the initial microlayer thickness during the microlayer formation and it’s contribution to the bubble growth. An experiment will be performed in a borosilicate glass vessel. Bubbles will generate from artificial cavity on a laser treated stainless steel surface. The laser treated surfaces will influence the microlayer formation and bubble growth. An empirical expression will be developed to capture the initial microlayer thickness as a function of surface roughness profile (height in this work).

Investigation process: experimental and numerical

- Capturing nucleated bubble of degassed deionized water using high-speed imaging techiques for different heaters
- Processing the captured results using image processing tools
- Consideration of uncertainities related to experiment and data processing
- Analyzing experimental data setup
- Numerical calculation of associated heat transfers using MATLAB
- Development of an empirical correlation based on experimental data.

Department: Experimental Thermal Fluid Dynamics

Contact: Sarker, Debasish, Dr. Ding, Wei

Requirements

• Academic studies in the field of process engineering, chemical engineering, mechanical engineering or comparable fields of study.
• Knowledge in heat and mass transfer phenomena
• Expertise in MATLAB or similar coding

Conditions

• Literature research – nucleate bubble dynamics
• Experiment using imaging techniques
• Processing the experimental results
• Analyzing the results

Online application

Please apply online: english / german

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Potential for a German ammonia economy

Student practical training / 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.
Ammonia is the second most produced chemical worldwide and the basis of all nitrogen-based fertilizers. It has also been proposed as an energy carrier alternative to hydrogen. Ammonia produced using renewable resources is more expensive than the conventional one, but it compares favorably to hydrogen and other energy storage technologies such as lithium ion batteries.
The objective of the thesis is to evaluate the economic feasibility of producing ammonia using renewable energies in Germany (or any other European country).

Task:
• Production costs of renewable hydrogen and ammonia.
• Production costs of other H and N based-fuels: ammonium hydroxide and urea, methanol.
• Distribution costs for the aforementioned fuels.
• Wells-to-wheels economic assessment.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Rodriguez Garcia, Gonzalo, Dr. Kryk, Holger, Prof. Dr. Hampel, Uwe

Requirements

• Student of Chemical or Process Engineering, Energy Technology (Renewable Energy Systems), Business Engineering 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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Feasibility of a renewable powered N-fertilizer pro-duction in Germany

Student practical training / 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.
Ammonia is the second most produced chemical worldwide and the basis of all nitrogen-based fertilizers. Novel production paths include the combination of Haber-Bosch synthesis and water electrolysis as well as solid state ammonia synthesis.
The objective of the thesis is to evaluate the technical feasibility of operating an ammonia production facility using one of the aforementioned technologies in combination with a renewable energy source.

Tasks:
• Collect data on ammonia production using renewable energies.
• Conduct an energy balance of a wind farm/solar farm capable of covering all electricity and N-fertilizer needs.
• Evaluate the combined use of battery storage and wind turbines for an island grid.
• Assess the feasibility of producing fertilizers other than ammonia using also renewable energies.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Rodriguez Garcia, Gonzalo, Dr. Kryk, Holger, Prof. Dr. Hampel, Uwe

Requirements

• Student of Chemical, Process or Electrical Engineering, Energy Technology (Renewable Energy Systems) or similar.
• Experience with Aspen Plus, ChemCAD or similar is not required, but desirable.
• High level of English.

Conditions

• 4-6 Months
• Starting as soon as possible

Online application

Please apply online: english / german

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Experimentelle Labor-Untersuchungen zur Zink-korrosion in borsäurehaltigen Kühlmittellösungen sowie zur späteren Abscheidung von Zinkboraten an Heißstellen im Kühlkreislauf

Student practical training / compulsory internship

Allgemeine Beschreibung:
Das Institut für Fluiddynamik im Helmholtz-Zentrum Dresden-Rossendorf (HZDR) beschäftigt sich unter anderem mit Fragen der Optimierung der Si-cherheit von Notkühlsystemen, welche bei Störfällen in AKW’s zum Einsatz kommen.
Im Rahmen eines hierzu derzeit laufenden Forschungsprojektes soll u.a. mit Hilfe von Versuchen im Labormaßstab untersucht werden, wie schnell Zinkbleche oder verzinkte Stahlteile in üblichen borsäurehaltigen Kühlmittellösungen von Kernkraftwerken korrodieren.
Weiter soll ermittelt werden, ob und wie stark sich dabei gebildete Zinkborate später an Heißstellen des so simulierten Notkühlkreislaufes abscheiden können und ob es dadurch zu Verblockungen in Kühlkanälen kommen könnte.
Die Versuchsreihen sollen hauptsächlich in einer für diese Zwecke bereits aufgebauten Labor-Versuchsanlage durchgeführt werden. Dabei sollen die Einflüsse verschiedener Parameter wie unterschiedliche zeitliche Temperaturverläufe oder Strömungsgeschwindigkeiten mit berücksichtigt werden, welche aus Abschätzungen zu verschiedenen Störfall-Szenarien von Kernkraft-werken bekannt sind.
Für die Durchführung und Auswertung dieser Versuche werden solide chemische und technische Grundkenntnisse benötigt. Selbstverständlich erfolgt dazu eine gründliche Einarbeitung und fachliche Betreuung durch zuständige Mitarbeiter der Arbeitsgruppe.
Die Arbeitsgruppe Verfahrenschemie der Abteilung Experimentelle Thermo-fluiddynamik bietet für einen Studenten der Studiengänge Chemie-Ingenieurwesen, Chemie, Physik, Verfahrenstechnik oder ähnlicher fachlicher Ausrichtung eine Praktikumstätigkeit mit den Schwerpunkten technische, analytische und physikalische Chemie.

Mögliche Aufgaben:
• Durchführung und Auswertung von Laborexperimenten mit einer Versuchsanlage zur Untersuchung der Zinkkorrosion in borsäurehaltigen Kühlmittellösungen.
• Untersuchungen zur Geschwindigkeit der Zinkauflösung/ Zinkfrei-setzung in Abhängigkeit verschiedener, zeitlich veränderlicher Parameter wie Temperatur, Strömungsverhältnisse oder Änderungen in der Kühlmittelchemie.
• Parallel dazu die Untersuchung von Zinkboratabscheidungen an Heißstellen in der kombinierten Labor-Versuchsanlage

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Kryk, Holger, Dr. Harm, Ulrich

Requirements

• Student(in) der Studiengänge Chemieingenieurwesen, Chemie, Phy-sik, Verfahrenstechnik oder ähnlicher fachlicher Ausrichtung.
• Hohe Genauigkeit und Sorgfalt bei der Arbeit.
• Fleiß und Freude am experimentellen Arbeiten.

Conditions

Nach Vereinbarung, möglich ab Februar 2017 oder später.

Online application

Please apply online: english / german

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Synthesis and characterization of isotope specific 'in-house standards' for the analysis of boron and aluminium in very low concentrations in SiO2-phases by secondary ion mass spectrometry

Student practical training / Master theses / Diploma theses / compulsory internship / volunteer internship

Secondary Ion Mass Spectrometry (SIMS) is a microanalytical method with a very good lateral and depth resolution combined with excellent limits of detection as well as a weak degree of destruction.
However, the method is very matrix sensitive and requires matrix adapted reference materials. Actually there are no certified reference materials available for mineralogical studies. Therefore most SIMS labs use so-called ‘in-house ’ standards.
For the analysis of SiO2-phases doped silica glasses may be used. Ion implantation has proven its worth as a robust method of doping. The aim of the work is the production and characterization of such ‘in-house’ standards for 10B, 11B and 27Al.

Department: Analytics

Contact: Dr. Renno, Axel

Requirements

•You study geosciences, chemistry, physics or material's sciences
•You are interested in mineralogical and analytical problems
•You are interested in modern analytical techniques
•You show initiative and good teamwork skills

Links:

Online application

Please apply online: english / german

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Experimental visualisation of particle-bubble interactions

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

Froth flotation is a separation process which plays a major role in the mining industry. Bubble-particle interactions are the very heart of this process, largely used for the capture of valuable commodities such as rare earth metals. The Institute of Fluid Dynamics of the research centre Helmholtz-Zentrum Dresden-Rossendorf (Germany) is making a bold move towards investigating the capture of mineral particles by rising bubbles. The Institute seeks a student to deploy high-speed imaging techniques and to observe the collision and attachment of particles falling on a bubble surface.

Tasks:
•Literature survey on particle attachment to bubble surface and froth flotation
•Visualisation with a high-speed camera of the attachment of falling solid particles on the surface of bubble
•Image processing of particle-bubble interactions

Duration: 6 Months

Financial compensation: yes

Language course: The HZDR offers German courses free of charge (not compulsory)

International applications: Yes, we welcome international applicants. It is preferable if the present internship is a compulsory part of your studies.

References
[1] Lecrivain G., et al., Attachment of solid elongated particles on a gas bubble surface. International Journal of Multiphase Flow 71, p. 83-93, 2015
[2] Lecrivain G., et al., Direct numerical simulation of a particle attachment to an immersed bubble. Physics of Fluids 28, 083301, 2016

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Lecrivain, Gregory

Requirements

•Interest in fluid mechanics
•High level of autonomy
•Enthusiasm for experimental work

Online application

Please apply online: english / german

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Auswertung von Experimenten zur Untersuchung des Übergangs vom Blasen- zum Filmsieden

Bachelor theses / Master theses / Diploma theses

Siedevorgänge spielen in verfahrenstechnischen Prozessen eine zentrale technologische und wirtschaftliche Rolle. Eine zuverlässige und präzise Beschreibung dieser Phänomene ist von entscheidender Bedeutung für die Sicherheit und Effizienz industrieller Anlagen.
Die Beschreibung von komplexen Wärmeübergangsprozessen mit Methoden der Strömungssimulation gewinnt zunehmend an Bedeutung. Zur Unterstützung der Softwareentwicklung für die Beschreibung des Übergangs von Blasen- zu Filmsieden werden am HZDR Kältemittelexperimente im Bereich sehr hoher Wärmeströme durchgeführt. Für die Messungen werden eine Infrarotkamera und ein ultraschneller Röntgentomograph eingesetzt.
• Mitwirkung an Versuchsserien.
• Auswertung von Prozess- und Bilddaten.
• Aufstellen von Energiebilanzen.
• Entwicklung von Methoden zur Bilddatenverarbeitung.
• Automatisierung der Auswertung der gewonnenen Daten.
• Vergleich der Versuchsergebnisse mit etablierten Modellen.

Department: Experimental Thermal Fluid Dynamics

Contact: Geißler, Thomas

Requirements

• Studium im Bereich Verfahrenstechnik, Chemieingenieurwesen, Maschinenbau, Physik.
• Kreative Problemlösefähigkeiten.
• Integrationswille in eine bestehende Arbeitsgruppe.
• Sicherer Umgang mit Bürosoftware, Kenntnisse Programmierung.

Online application

Please apply online: english / german

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Tracking of autonomous, flow following sensor particles

Master theses / Diploma theses / Student Assistant

Foto: AutoSens_StirredReactor ©Copyright: fwdf (Mailgruppe)Autonomous 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 task is focussed on the development of algorithms for reconstruction of the 3D movement trajectory of sensor particles based on data from the onboard inertial sensors, namely acceleration, angular rate and magnetic field, and an additional sensor for vertical position as function of the hydrostatic pressure. A favored approach is based on inertial navigation techniques that apply Bayes filters, e.g. Kalman filters, to fuse the sensor data. The developed algorithms are to be validated experimentally.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Reinecke, Sebastian

Requirements

• study programs in the fields of electrical engineering, mechatronics, mechanical engineering and related degree programs
• fundamentals of digital signal analysis, Bayes' filters, Kalman-filters, rigid body motion
• experimental skills
• data analysis in Matlab, Octave or C/C++
• self-regulating, independent work methods

Links:

Online application

Please apply online: english / german

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Magnetfeld-Beeinflussung paramagnetischer Ionen in wässrigen Lösungen

Bachelor theses / Master theses / Diploma theses / Student Assistant

Im Zentrum der Forschungsaktivitäten der Abteilung Magnetohydrodynamik des Institutes für
Fluiddynamik am Helmholtz-Zentrum Dresden-Rossendorf steht die Untersuchung und Nutzung der
Wechselwirkungen zwischen Strömungen elektrisch leitfähiger Flüssigkeiten und magnetischen
Feldern.
Ein interessanter Aspekt sind hierbei Kraftwirkungen inhomogener magnetischer Felder auf
magnetisierbare Teilchen in Flüssigkeiten, welche beispielsweise zum Mischen einer Suspension
oder zum Separieren von Teilchen aus einer Lösung genutzt werden können. Aktuelle
Forschungsaktivitäten untersuchen insbesondere das Verhalten paramagnetischer Ionen in
wässrigen Flüssigkeiten, die interessante Anwendungen z.B. in der hydrochemischen Verarbeitung
von Seltene-Erden-Metallen eröffnen könnten. Im Rahmen eines internationalen Kooperations-
projektes werden hierzu derzeit sowohl numerische als auch experimentelle Arbeiten im
Labormaßstab durchgeführt.
Dem Charakter der angestrebten studentischen Mitarbeit entsprechend werden aus dem
beschriebenen Umfeld der Forschungsaufgabe passende experimentelle oder numerische
Teilaufgaben definiert.

Institute: Institute of Fluid Dynamics

Contact: Dr. Mutschke, Gerd

Requirements

Vorkenntnisse der Strömungsmechanik sind erforderlich; bei der
Einarbeitung in das interdisziplinäre Umfeld werden Sie natürlich unterstützt.

Conditions

Umfang ca. 6 Wochenstunden. Die Vergütung der studentischen Tätigkeit erfolgt entsprechend der HZDR-Richtlinien.

Online application

Please apply online: english / german

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Thermo- /Fluiddynamic Properties for Liquid Metal Batteries

Student Assistant / Research Assistant

Foto: Experimental Liquid Metal Battery ©Copyright: Flüssigmetallbatterie Abteilung MagnetohydrodynamikIn contrast to conventional batteries, Liquid Metal Batteries feature all liquid anodes anodes (alkaline or alkaline earth metal), cathodes (transition metal or metal) and electrolytes (molten salts) at a temperature between 400 °C and 600 °C.
To simulate internal flow and the general thermochemical performance of the batteries, a couple of fluid properties like density, viscosity and heat capacity are needed for each of the cell material. The task is to collect the data (literature research), to arrange them in a database and to program functions in Python for the further use in simulations.
It is possible to continue the work on the topic in form of a project work or a final thesis.

Department: Magnetohydrodynamics

Contact: Dr. Nimtz, Michael, Dr. Weber, Norbert

Requirements

Studies of chemistry, mech. engineering or physics
Good English
Helpful: simple programming experience, basic knowledge of thermodynamics and fluiddynamics

Conditions

Approx. 10 h/week
Home office possible (weekly meeting at HZDR)
Duration: open-end (4 months minimum)
Start: immediately
Paid according to personal preconditions
Final thesis possible

Links:

Online application

Please apply online: english / german

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Charakterisierung des Stofftransports in einer Blasenströmung anhand tomographischer Daten

Student practical training / Master theses / Diploma theses / Student Assistant / compulsory internship

Blasensäulen sind aufgrund ihrer einfachen Bauweise ein beliebter Reaktortyp in der chemischen Industrie. Vor allem die Hydrodynamik und der Stofftransport in Blasensäulen sind für den Umsatz und die Selektivität chemischer Reaktionen von Bedeutung. In einer Blasenströmung wurden Messungen mit der ultraschnellen Röntgentomographie zum Stofftransport durchgeführt, welche nun genauer analysiert werden sollen. Ziel ist es charakteristische Größen für den Stofftransport und die Hydrodynamik zu extrahieren. Dazu sind vorhandene Auswertealgorithmen anzupassen und ggf. zu erweitern.

Department: Experimental Thermal Fluid Dynamics

Contact: Kipping, Ragna

Requirements

Online application

Please apply online: english / german

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Student assistant at the DeltaX School Lab

Student Assistant

Foto: SommerferienForscherWoche im Schülerlabor DeltaX ©Copyright: Jana GrämerDas Schülerlabor DeltaX macht die Forschung am Helmholtz-Zentrum Dresden-Rossendorf für Schülerinnen und Schüler erlebbar. Für ihre Betreuung und Unterstützung beim Experimentieren suchen wir Studierende, die Freude an der Vermittlung von Naturwissenschaften, Forschung und Technik haben. Bewerben Sie sich als studentische Hilfskraft im Schülerlabor DeltaX und werden Sie Teil eines jungen und aufgeschlossenen Teams.

Das Schülerlabor DeltaX bietet Schulklassen Experimentiertage zu den Themen:
- „Licht und Farbe“ (Klassen 5-10)
- „Magnetismus und Materialforschung“ (ab Klasse 10)
- „Radioaktivität und Strahlung“ (ab Klasse 9)

Department: Communication & Media Relations

Contact: Dr. Streller, Matthias, Gneist, Nadja

Requirements

- Studium eines naturwissenschaftlichen Faches
- Verbleibende Studiendauer mind. 2 Semester
- Freude an der Vermittlung von Naturwissenschaften und Forschung
- Gute bis sehr gute Noten

Conditions

- 5 - 10 h / Woche an ganzen Wochentagen
- Beginn der Einstellung nach Vereinbarung

Links:

Online application

Please apply online: english / german

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Convection in liquid metal batteries

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

Foto: Convection in liquid metal batteries ©Copyright: Dr. Norbert WeberLiquid metal batteries (LMBs) consist of a stable density stratification of two liquid metals, separated by a liquid salt electrolyte. They are a strong candidate for stationary energy storage in the electric grid. In order to build large cells, fluid dynamics in LMBs must be known. In frame of project work or a master thesis, an already available solver has to be validated. Especially the natural convection due to the strong heating of the electrolyte layer shall be investigated.

Depending on the interest of the candidate, other work on liquid metal batteries is possible, too. Please send your application directly via email to ensure a fast answer.

Department: Magnetohydrodynamics

Contact: Dr. Weber, Norbert

Requirements

• studies of informatics, chemistry, mechanical engineering, physics or similar
• good marks
• helpful: knowledge of C++, Linux, simulations (FVM)

Online application

Please apply online: english / german

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Untersuchungen der Hydrodynamik von dispersen Zweiphasenströmungen in komplexen Geometrien

Student practical training / Diploma theses / Student Assistant

Zweiphasenströmungen sind ein wesentlicher Bestandteil industrieller Anwendungen im Bereich der Wärmeübertragung, der chemischen Industrie oder der Kraftwerkstechnik. Häufig weisen die durchströmten Komponenten solcher Anlagen komplexe geometrische Bedingungen auf. Für einen sicheren und effizienten Betrieb ist die genaue Kenntnis der Hydrodynamik der resultierenden Strömungsvorgänge von essentieller Bedeutung. Dafür sollen experimentelle Untersuchungen mittels der ultraschnellen Röntgentomographie an einer thermohydraulischen Versuchsanlage durchgeführt werden. Ziel ist es einen Beitrag zur Beschreibung komplexer Strömungsvorgänge zu liefern.

Department: Experimental Thermal Fluid Dynamics

Contact: Neumann, Martin

Requirements

• Studium des Chemie-Ingenieurwesen, Verfahrenstechnik, oder ähnlichen Ingenieurstudiengängen
• Kenntnisse im Bereich der Datenauswertung mit Matlab von Vorteil
• Freude am experimentellen Arbeiten

Online application

Please apply online: english / german

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Trace element content and distribution in synthetic rutile – a SIMS study

Student practical training / Master theses

The trace element content of natural rutile bears very valuable mineralogical and petrogenetical information. In particular the 'Zr in rutile' and 'Si in rutile' geothermometer are very well studied. Equally important are the different partition coefficients for the 'geochemical twins” Nb – Ta, Zr – Hf, and U – Th. Secondary Ion Mass Spectrometry is a very sensitive, but matrix dependent microanalytical method. For this reason the usage matrix-matched reference materials is essential. The suitability of several synthetic rutile crystals as a SIMS reference material has to be examined by systematic SIMS measurements.

Department: Analytics

Contact: Dr. Renno, Axel

Requirements

Diploma or Master's thesis for students of earth science (mineralogy or geochemistry), analytical chemistry or materials sciences:
you are interested in mineralogical / crystal chemical problems
you are interested in modern analytical techniques
initiative and good teamwork skills

Online application

Please apply online: english / german

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Development of a proton beam stable embedding agent for minerals

Student practical training / Master theses / Diploma theses / compulsory internship / volunteer internship

Particle induced X-Ray Emission (PIXE) is a rarely used mineralogical analytical method. PIXE is used for laterally resolved detection and quantification of trace elements. The limits of detection are considerably better compared to the electron probe micro analysis (EPMA).
The Ion Beam Analysis Group at the Helmholtz-Institute Freiberg for Resource Technology uses several PIXE methods in close collaboration with the Ion Beam center (IBC) of the Helmholtz-Zentrum Dresden-Rossendorf to analyse minerals. We use a PIXE micro beam device as well as a new detector type a pnCCD detector, a so-called X-ray colour camera.
The analysis of minerals, embedded in epoxy resin like particle mounts or thin sections is greatly affected by instability under the influence of the proton beam. On this account a new embedding agent on a mineral base is necessary to develop.

The objective of the thesis is a systematic literature research for potential embedding agents on a mineral base as well as the validation of beam stability of these materials.

Department: Analytics

Contact: Dr. Renno, Axel

Requirements

Diploma or Master's thesis for earth scientist (mineralogy or geochemistry), analytical chemistry or materials sciences:
you are interested in mineralogical / crystal chemical problems
you are interested in modern analytical techniques
initiative and good teamwork skills

Online application

Please apply online: english / german

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Parallelisation of an algorithm for projection data reassignment

Student practical training / Bachelor theses / Student Assistant

With the spatial high resolution gamma-ray computed tomography measurement system for high energy gamma radiation (662 keV) dense objects with up to a diameter of 700 mm can be no-destructively analysed with an in-plane resolution of approximately 2 mm. The available single core C++ program (32-bit compiler) has to be analysed concerning parallelisation, i.e. multi core CPU and/or many core GPU) and has to be optimised.

Department: Experimental Thermal Fluid Dynamics

Requirements

- Handling with CUDA (NVIDIA)
- Handling with LINUX UBUNTU
- Advanced mathematic knwoledge

Links:

Online application

Please apply online: english / german

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Implementation of a performance optimized ray reassignment algorithm

Student practical training / Bachelor theses / Student Assistant

With the available ultrafast X-ray electron beam computed tomography scanner of the HZDR up to 8000 non-superimposed cross-sectional images can be contactless obtained per second. For an effective implementation of standard reconstruction algorithms a ray reassignment must be performed on GPUs.

Department: Experimental Thermal Fluid Dynamics

Requirements

- Handling with CUDA (NVIDIA)
- Handling with LINUX Ubuntu
- Advanced mathematic knowledge

Links:

Online application

Please apply online: english / german

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A new coating procedure for minerals to be used for ultratrace element determination with SIMS

Student practical training / Master theses / Diploma theses / compulsory internship / volunteer internship

Nonconductive mineralogical samples, to be analysed by Secondary Ion Mass Spectrometry (SIMS) for ultratrace elements must be coated by a very thin conductive layer to prevent charging. Gold is used in most instances due to its high purity. For ultratrace element determination in the field of mineral and metallic resources we try to avoid a contamination of the sample chamber by gold. Consequently other materials on the basis of doped ultrapure silicon have to be tested for their suitability.
The thesis is focused on the basic feasibility of such coatings and the characterization of the coating regarding evenness, coating thickness, and electrical conductivity.
The coating experiments and the characterization will be systematically conducted for several groups of minerals like sulfides, oxides and silicates.

Department: Analytics

Contact: Dr. Renno, Axel

Requirements

Diploma or Master's thesis for earth scientist (mineralogy or geochemistry), analytical chemistry or physics:
you are interested in mineralogical / crystal chemical problems
you are interested in modern analytical techniques
initiative and good teamwork skills

Online application

Please apply online: english / german

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Experimental studies on the partial oxidation of Isobutane with oxygen in a micro reactor, as well as their analysis.

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

The Institute of fluid dynamics in the Helmholtz-Zentrum Dresden-Rossendorf (HZG) deals among other things with the experimental investigation and simulation of chemical processes of multi phase.
In the framework of the energy Alliance project "energy-efficient chemical multiphase processes" examines the partial oxidation of Isobutane in liquid or of supercritical phase with oxygen by means of a specially designed micro reactor to TBHP. This to the influence of different initiators, pressures, temperatures, additives and reactant ratios etc. are examined. The reaction product is analysed using gas chromatography mass spectrometry (GC-MS).
The Working Group process chemistry of Department experimental Tuhh offers for one or two semester students of the departments of chemical engineering, chemistry, physics, engineering, or similar professional orientation activities with a focus on technical, analytical, and physical chemistry.

Analytical examinations by GC-MS.

Ø Studies on the stability of the samples, reproducibility, precision and accuracy of measurements and evaluation.

· Performing the reaction under variation of one of the specified parameters.

Ø Response technical studies on the influence of one of the above reaction parameters and evaluation.

· Performing the reaction under variation of one of the specified parameters.

Ø Response technical studies on the influence of one of the above reaction parameters and evaluation.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Willms, Thomas, Dr. Kryk, Holger

Requirements

• Student of the departments of chemical engineering, chemistry, physics, engineering or similar professional orientation.
• High accuracy and care at work.
• Hard work and joy in experimental work.
· Student of the departments of chemical engineering, chemistry, physics, engineering or similar professional orientation.

Conditions

at least 5 month, begin as of now possible

Online application

Please apply online: english / german

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Liquid mixing and mass transfer measurements in a bubble column reactor with internals

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

Bubble column reactors are apparatuses of choice regarding multiphase flows/reactions in the chemical process industry. Processes like the Fischer-Tropsch-synthesis are typically carried out in a bubble column reactor. Since most of the reactions are of exothermic nature, the produced heat has to be sufficiently removed to guarantee a stable reactor operation. Therefore, longitudinal flow heat exchanging tubes, which alter the flow behavior of the phases and cover a large portion of the reactor’s cross sectional area, are inserted into the bubble column reactor. For a secure construction of a bubble column with an internal tube bundle heat exchanger, its influence on hydrodynamic, mass transfer and liquid mixing needs to be investigated.

Department: Experimental Thermal Fluid Dynamics

Contact: Möller, Felix

Requirements

• Student of Process or Chemical Engineering, Technical Chemistry or comparable fields of study
• Enthusiasm in experimental work
• Knowledge in plant commissioning and mass transfer phenomena are welcome, but not compulsory
• Knowledge in Matlab for data acquisition

Conditions

• Literature research in the field of bubble column reactors with internals and measurement techniques
• Investigation of liquid mixing and mass transfer in bubble columns with internals using oxygen proebes and wire-mesh sensors
• Measurement of mass transfer in bubble column with internals
• Model development for bubble columns with internals, maybe compartment modeling

Links:

Online application

Please apply online: english / german

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Untersuchung des Einflusses von Regularisierungsmethoden auf Bildrekonstruktionsalgorithmen

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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Laterally resolved chemical analysis for silver in feldspar minerals and glasses of feldspar composition by means of Particle Induced X-Ray Emision (PIXE) – limits of detection

Master theses / Diploma theses / compulsory internship / volunteer internship

The substitution of silver for the alkali ions (Me+) in feldspar minerals and glasses of feldspar composition is promoted by the very similar chrystal chemical properties of the Ag+ ion. In the framework of the bachelor thesis the fitness for all threee PIXE methods in use at the IBC for the laterally resolved analysis of silver is to be tested

Department: Analytics

Contact: Dr. Renno, Axel, Dr. Munnik, Frans

Requirements

• you are a student of geoscience, chemistry or materials sciences
• you are interested in mineralogical / crystal chemical problems
• you are interested in modern analytical techniques
• initiative and good teamwork skills

Links:

Online application

Please apply online: english / german

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