Practical trainings, student assistants and theses

Experimental investigation of two phase (Liquid-Gas) flow regime within a porous frit bubble generator, and its influence on bubble size and gas fraction distribution in the downcomer. (Id 367)

Bachelor theses / Master theses / Diploma theses / Compulsory internship

Understanding of bubble generation mechanism and evaluation of bubble size is critical for any process (e.g. reaction in a bubble column, mineral flotation process etc.). The size of the bubbles and its flow regime in the column/reactor determines the hydrodynamics which influences the reaction kinetics or recovery of the minerals in a flotation cell. There are different methods to generate microbubbles, one of them using a porous frit (commonly used in the industries due to simple design and its robustness). Two-phase flow regimes (slug, plug, annular, bubbly etc.) are well investigated in vertical and horizontal tube/pipe configuration. This study is focused on a porous frit bubble generator with an aim to understand the regimes within the frit and its influence on the rest of the system.

Research question:

Different flow regimes are observed in the frit at varying process conditions and the regimes influences the bubble size and the gas phase distribution in the downcomer.

Primary objectives of this study are:

1. Identifying the flow regime of the bubbles within the frit at varying process condition using the shadowgraphy technique,
2. Quantification of bubble size using a process microscope as it moves down the downcomer (vertical tube downstream of the frit) and,
3. Determine the gas fraction distribution using a wire mesh sensor.

For details please refer:

https://tu-dresden.de/ing/maschinenwesen/ifvu/tpg/ressourcen/dateien/shk/2022-07-20_RFC_Vaishakh.pdf?lang=en

Department: Transport processes at interfaces

Contact: Tholan, Vaishakh, Dr. Heitkam, Sascha

Requirements

1. Field of study: chemical engineering, process engineering, fluid mechanics, physics or similar field of study,
2. High motivation for experimental research,
3. Understanding of fluid mechanics,
4. Working independently,
5. Matlab/Python and Image post processing will be an added advantage.

Conditions

1.Working/Collaboration in an international team,
2. Will gain experience in sophisticated measurement techniques used in experimental fluid dynamics,
3. Duration: at least 6 months,
4. Location: TU Dresden.

Online application

Please apply online: english / german

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Development of an automation system for simulations in materials science (Id 361)

Master theses / Student Assistant / Research Assistant

As a member of the Helmholtz Association of German Research Centers, the HZDR employs about 1,400 people. The Center's focus is on interdisciplinary research in the areas of energy, health, and matter.
The Center for Advanced Systems Understanding (CASUS) is a German-Polish research center for data-intensive digital systems research. CASUS was founded in 2019 in Görlitz and conducts digital interdisciplinary systems research in various fields such as earth systems research, systems biology, and materials science.

We are looking for motivated, creative, and curious students to help us create and automate workflows for generating interatomic potentials in matter under extreme conditions.

The scope of your job
The Department of Matter under Extreme Conditions at CASUS is working on the generation of accurate machine learning interatomic potentials (ML-IAPs), which can be used to determine the physical properties of matter under extreme conditions. For this purpose, training data are generated with DFT codes such as VASP or Abinit and used to create ML-IAPs by applying appropriate Hamiltonian models.

This is a multi-stage process that so far requires a lot of manual work. In this work, robust workflows and test routines will be designed both to generate ML-IAPs using AiiDA and to verify the generated ML-IAPs with respect to the accuracy of the calculated physical properties, primarily to increase the robustness and reproducibility of the process. Prior knowledge of materials science simulations is not required!

Department: Department of Matter under extreme Conditions

Contact: Dr. Cangi, Attila, Ramakrishna, Kushal

Requirements

  • Bachelor's degree in computer science or related field
  • Experience with Python, C++
  • Experience with Git
  • Ability to work in a team
  • Good language skills in English
  • Experience with software automation or database systems (optional)
  • Experience with scientific software development (optional)

Conditions

Tasks this project might involve:

  • Research of existing solutions for the automation of simulations
  • Development of the Python-based workflow with AiiDA
  • API development for the control of individual process steps

What we offer:

  • An exciting, open, and international research environment under excellent scientific and technical working conditions
  • High level of scientific networking and scientific excellence
  • Employment as a student assistant (optional, working hours by arrangement)

Links:

Online application

Please apply online: english / german

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Characterization of radiotracers for tumor imaging (Id 360)

Bachelor theses / Master theses / Compulsory internship

Within the framework of various research projects of the Department of Radiopharmaceutical and Chemical Biology, novel radiotracers, labeled for example with the imaging radionuclides fluorine-18, iodine-123 or copper-64, will be evaluated preclinically in vitro and in vivo. In addition, novel cell models (2D, 3D) will be established to be biochemically and biologically characterized. Depending on the prerequisite (field of study) and main interest, a variety of chemical, radiochemical, biochemical, molecular and cell biological as well as radiopharmacological methods and techniques can be learned and applied. While working scientifically on your topic, you will also acquire transferable key skills such as scientific writing, presentation skills, critical thinking and project planning

Department: Radiopharmaceutical and Chemical Biology

Contact: Prof. Dr. Pietzsch, Jens

Requirements

  • Studies/degree in chemistry, biochemistry, biology or a related field
  • Strong interest in scientific work in an interdisciplinary team
  • Independent working style and excellent communication skills
  • High level of commitment and motivation
  • Willingness to work with open radioactive materials

Conditions

  • Start usually at the beginning of the semester or by arrangement
  • Internship duration at least 16 weeks

Online application

Please apply online: english / german

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Development of a numerical model for the simulation of aerosol spread (Id 349)

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

As part of the CORAERO joint project (Airborne Transmission of SARS Coronavirus - From Fundamental Science to Efficient Air Cleaning Systems) funded by the Helmholtz Association, we are working on scientific issues relating to the formation of virus-laden aerosols, their thermodynamics and propagation in rooms, as well as strategies and technologies to prevent aerosol-borne infections.

In this context, we are looking for a highly motivated student (f/m/d) to work on the development of numerical models for the simulation of dynamic situations. Ideally, the model should reproduce the spread of exhaled aerosols while a person walks. An immersed boundary method is available in the group and will be further developed.

Institute: Institute of Fluid Dynamics

Contact: Dr. Lecrivain, Gregory, Cavagnola, Marco Alejandro

Requirements

  • General interest in fluid mechanics
  • Preliminary experience in code development (c++) is desirable
  • Good written and oral communication skills in either English or German

Conditions

  • Either an immediate start or a start in 2023 is possible
  • Duration of the internship is anticipated to be 6 months but can be modified according to study regulations
  • Remuneration according to HZDR internal regulations

Online application

Please apply online: english / german

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Self-organized nanopattern formation on crystalline SiGe surfaces (Id 342)

Master theses / Diploma theses

Foto: AFM images of ion-induced surface patternings ©Copyright: Dr. Denise ErbVarious metals, semiconductors, and oxides form regular nanoscale surface patterns in a complex process of self-assembly under low energy ion irradiation. While the elemental semiconductors Si and Ge have been extensively studied in this respect, there is no such investigation for alloys of Si and Ge. We want to explore which nanoscale pattern morphologies can emerge on SiGe surfaces and how they can be modified via the conditions of ion irradiation. We expect to obtain new insights into the complex process of ion-induced nanopattern formation in technologically relevant materials.
This work comprises the preparation of nanopatterned surfaces by low energy ion irradiation, imaging these surfaces surfaces by atomic force microscopy and electron microscopy, the quantitative analysis of these data, as well as simulating the patterning process based on continuum equations or kinetic MonteCarlo models.
The project provides an introduction to research at a large scale facility (Ion Beam Center IBC) and opportunities for networking with HZDR specialists (f/m/d) on nanoscale surface modification and characterization.

Department: Ion Beam Center

Contact: Dr. Erb, Denise

Requirements

-- completed B.Sc. studies or Vordiplom in experimental physics, materials science, or related subject
-- good command of German and/or English
-- ability to work independently and systematically

Conditions

-- place of work: HZDR, location Rossendorf
-- project duration: 12 months, flexible starting time

Links:

Online application

Please apply online: english / german

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Self-organized nanopattern formation on crystalline surfaces of III-V semiconductors (Id 341)

Master theses / Diploma theses

Foto: AFM images of ion-induced surface patternings ©Copyright: Dr. Denise ErbVarious metals, semiconductors, and oxides form regular nanoscale surface patterns in a complex process of self-assembly under low energy ion irradiation. Depending on the experimental conditions nanopatterns of very different morphologies will form. They can be categorized into either the erosive or diffusive regime – depending on the dominant mass transport processes on the surface. For compound semiconductors the erosive regime has rarely been investigated so far. We want to find out under which conditions the expected nanopattern formation in the diffusive regime takes place. We expect to obtain new insights into the complex process of ion-induced nanopattern formation in technologically relevant materials.
This work comprises the preparation of nanopatterned surfaces by low energy ion irradiation, imaging these surfaces surfaces by atomic force microscopy and electron microscopy, the quantitative analysis of these data, as well as simulating the patterning process based on continuum equations or kinetic MonteCarlo models.
The project provides an introduction to research at a large scale facility (Ion Beam Center IBC) and opportunities for networking with HZDR specialists (f/m/d) on nanoscale surface modification and characterization.

Department: Ion Beam Center

Contact: Dr. Erb, Denise

Requirements

-- completed B.Sc. studies or Vordiplom in experimental physics, materials science, or related subject
-- good command of German and/or English
-- ability to work independently and systematically

Conditions

-- place of work: HZDR, location Rossendorf
-- project duration: 12 months, flexible starting time

Links:

Online application

Please apply online: english / german

Druckversion


Self-organized nanopattern formation on crystalline GaAs and InAs surfaces (Id 340)

Master theses / Diploma theses

Foto: AFM images of ion-induced surface patternings ©Copyright: Dr. Denise ErbVarious metals, semiconductors, and oxides form regular nanoscale surface patterns in a complex process of self-assembly under low energy ion irradiation. Studies of the elemental semiconductors Si and Ge have shown that the symmetry of their crystalline surface strongly influences the morphology of those nanopatterns. However, only one particular surface orientation has been studied analogously for the compound semiconductors GaAs and InAs. While for these materials, the nanopattern morphology is mainly attributed to their compound character, a significant additional influence of the surface crystal structure is expected. We want to demonstrate this by investigation the ion-induced pattern formation on crystalline GaAs and InAs with various surface orientations. The resulting surface patterns may find application in the bottom-up fabrication of complex nanostructured systems.
This work comprises the preparation of nanopatterned surfaces by low energy ion irradiation, imaging these surfaces by atomic force microscopy and scanning tunnelling microscopy, the quantitative analysis of these data, as well as simulations of the patterning process based on continuum equations or kinetic MonteCarlo models.
The project provides an introduction to research at a large scale facility (Ion Beam Center IBC) and opportunities for networking with HZDR specialists (f/m/d) on nanoscale surface modification and characterization.

Department: Ion Beam Center

Contact: Dr. Erb, Denise

Requirements

-- completed B.Sc. studies or Vordiplom in experimental physics, materials science, or related subject
-- good command of German and/or English
-- ability to work independently and systematically

Conditions

-- place of work: HZDR, location Rossendorf
-- project duration: 12 months, flexible starting time

Links:

Online application

Please apply online: english / german

Druckversion


Optical properties of Ag nanocube ensembles (Id 339)

Master theses / Diploma theses

Ensembles of nanoscale metallic objects such as Ag nanocubes exhibit particular optical properties, which can be influenced by size, shape and spatial arrangement of these objects. Ion beam based techniques enable the preparation of nanopatterned surfaces, on which Ag nanocubes can be arranged in a regular fashion, as well as the modification of the nanocube shape by ion erosion. Thus the effects of changes in arrangement and shape on the optical properties of the ensemble can be studied.
This work comprises the preparation of nanopatterned surfaces by low energy ion irradiation, the arrangement of Ag nanocubes on such surfaces and their deformation by ion beam erosion, the imaging of theses sample systems by atomic force microscopy and scanning electron microscopy, the measurement of optical properties by cathodoluminescence and ellipsometry, and the quantitative analysis of the obtained data.
The project provides an introduction to research at a large scale facility (IBC) and opportunities for networking with HZDR specialists (f/m/d) on nanoscale surface modification and characterization.

Department: Ion Beam Center

Contact: Dr. Erb, Denise

Requirements

-- completed B.Sc. studies or Vordiplom in experimental physics, materials science, or related subject
-- good command of German and/or English
-- ability to work independently and systematically

Conditions

-- place of work: HZDR, location Rossendorf
-- project duration: 12 months, flexible starting time

Links:

Online application

Please apply online: english / german

Druckversion


Development of an automation system for materials science simulations (Id 337)

Master theses / Diploma theses / Student Assistant

Foto: MALA ©Copyright: Dr. Attila CangiThe Center for Advanced Systems Understanding (CASUS) is a German-Polish research center for data-intensive digital systems research. CASUS was founded in 2019 in Görlitz and conducts digital interdisciplinary systems research in various fields such as earth systems research, systems biology, and materials science.

We are looking for motivated, creative, and curious students to help us automate generating simulation data for machine-learning projects in the field of matter under extreme conditions.

The scope of your job
The Department Matter under Extreme Conditions at CASUS investigates how materials properties can be predicted based on machine-learning algorithms. This requires large amounts of simulation data. Generating this data requires a large degree of user input. In this project, you will investigate if and how existing tools for automation in the field of materials science can be integrated into computational workflows to drastically speed up data acquisition. This involves improving the in-house software and combining it with larger software suites. Besides ease-of-use, another focus of these workflows should be reproducibility. No prior knowledge of materials science simulation is required!

Tasks for this thesis might involve:

  • Literature research on existing solutions for the automation of simulations
  • Development and improvement of the existing Python workflows
  • Integration of existing workflows in larger software suites
  • Development of a graphical user interface, potentially web based

Department: Department of Matter under extreme Conditions

Contact: Fiedler, Lenz, Dr. Cangi, Attila

Requirements

  • Bachelor in computer science or related field
  • Experience with Python, JavaScript or Java
  • Ability to work in a team
  • Good language skills in English
  • Experience with software automation or database systems (optional)
  • Experience with Git or SVN (optional)
  • Experience with scientific software development (optional)

Conditions

  • A vibrant research community in an open, diverse, and international work environment
  • Scientific excellence and extensive professional networking opportunities
  • Compensation as student researcher (optional, working hours to be determined)

Online application

Please apply online: english / german

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Motion tracking of autonomous sensor particles in industrial vessels (Id 335)

Master theses / Diploma theses / Compulsory internship

Foto: AutoSens_StirredReactor ©Copyright: fwdf (Mailgruppe)Data acquisition in large industrial vessels such as biogas fermenters or wastewater treatment plants is limited to local measurement points due to limited access to the vessel and the non-transparency of the fluid. To optimize these kinds of plants, the three-dimensional flow field and the spatial distribution of fluid properties such as temperature and electrical conductivity inside the vessel must be known. This can be achieved by the autonomous flow-following sensor particles developed by the HZDR. Equipped with a pressure sensor, an accelerometer, two gyroscopes and a magnetometer, the sensor particle can track the movement inside the vessels and derive the flow field from that. Additionally, the sensor particle gets position information by an ultra-wide-band based localization module (like GPS) as soon as it is on the fluid surface. The motion of the sensor particle is currently tracked with an error-state Kalman filter and yields a reliable tracking of the velocity and position, respectively. However, the tracking time is limited by the propagation of uncertainties of the inertial sensors through the filter. The objective of this master thesis is to extend this tracking time by the use of more advanced tracking algorithms like particle filter or other types of Kalman filters. This includes the following tasks:

  • Literature review of advanced filters for motion tracking
  • Theoretical comparison and implementing the most promising algorithm in Python
  • Verification and performance analysis based on experimental data

Department: Experimental Thermal Fluid Dynamics

Contact: Buntkiel, Lukas, Dr. Reinecke, Sebastian

Requirements

  • Studies in the area of electrical, mechatronic, mechanical engineering or similar
  • Basics of measurement uncertainty, digital signal processing
  • Data analysis in Python
  • Independent and structured way of working

Conditions

  • Start possible at any time
  • Duration according to the respective study regulations

Links:

Online application

Please apply online: english / german

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Experimental investigation of influence of interfacial viscoelasticity on the dripping to jetting transition (Id 333)

School practical training / Student practical training / Bachelor theses / Master theses / Compulsory internship

Foto: Capillary with jetting liquid-liquid interface ©Copyright: Milad EftekhariLiquid jets are unstable and eventually form droplets to minimize the surface energy with the surrounding fluid. The transition from dripping to jetting and dynamics of the droplet pinch-off have been studied extensively for various systems, from pure Newtonian fluids to complex non-Newtonian liquids. The jetting process has received significant attention as it is a critical step in various three-dimensional (3D) printing techniques such as dropwise additive manufacturing and the direct ink writing method. In most of the applications surface active materials such as surfactants, nanoparticles, and polymers exist in the systems. The presence of surface-active materials reduces the liquid-fluid surface energies and in some cases generates a viscoelastic layer at the interface.
In this research, we aim to study the influence of interfacial viscoelasticity on the dripping to jetting transition. The study is conducted by the injection of an aqueous phase (nanoparticle dispersions) into an oil phase that contains surfactants over a wide range of flow rates. We tune the magnitude of interfacial viscoelasticity by changing the concentration of surfactants and nanoparticles.
Research question:
Does the dripping to jetting transition (critical flow rate) linearly increase by increasing the interfacial viscoelasticity?

Experiments:

1. Measurements of interfacial tension and surface elasticity for a range of particle and surfactant concentration using Profile analysis tensiometry, and Langmuir trough.
2. Dripping to jetting experiments for the selected systems using high-speed cameras and in-house setups.

Department: Transport processes at interfaces

Contact: Eftekhari, Milad, Dr. Schwarzenberger, Karin

Requirements

  • Field of study: chemical engineering, process engineering, fluid mechanics, or similar focus in chemistry or physics
  • Experience with laboratory work and imaging measurement techniques is beneficial

Conditions

  • Working in an international team
  • Duration: at least 6 months
  • Location: Dresden-Rossendorf

Online application

Please apply online: english / german

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Organisch-chemische Synthese neuer Radioliganden für die Diagnostik und Therapie von Krebserkrankungen (Id 295)

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

Wir beschäftigen uns mit der Entwicklung von PET-Radiotracern, die Rezeptoren im Tumormikromilieu (TME = tumor microenvironment) für die Diagnostik und Therapie von Krebs sichtbar machen. Dazu werden geeignete tumoraffine Leitstrukturen identifiziert (niedermolekulare organische Moleküle, Peptide und Peptidomimetika), synthetisiert und mit einem geeigneten Radionuklid kovalent (z. B. Fluor-18, Iod-123) oder über einen Chelator (z. B. Gallium-68, Lutetium-177) markiert. Diese Radioliganden werden in vitro an Tumorzelllinien und in vivo im Tiermodell hinsichtlich einer Anwendung in der Nuklearmedizin getestet. Langfristiges Ziel ist die Translation der entwickelten Radiotracer in die Klinik als Diagnosewerkzeug (PET/CT) oder nach Markierung mit einem Beta- oder Alphastrahler für die Endoradiotherapie von Tumorerkrankungen.
Im Rahmen eines Studentenpraktikums oder einer Abschlussarbeit (Bachelor/Master/Diplom) sollen organische Wirkstoffmoleküle synthetisiert und für eine anschließende radiochemische Markierung modifiziert werden. Die neuen Radioliganden werden dann biologisch in vitro und in vivo untersucht.

Department: Translational TME Ligands

Contact: Dr. Stadlbauer, Sven, Sachse, Frederik

Requirements

  • Studium der Chemie
  • Gute Noten in organischer Synthesechemie
  • Fähigkeit sich in ein interdisziplinäres Wissenschaftler-Team einzugliedern
  • Bereitschaft zum Umgang mit Radioaktivität
  • Gute Kenntnisse der deutschen und englischen Sprache

Conditions

  • Beginn nach Absprache jederzeit möglich
  • Praktikumsdauer mindestens 8 Wochen, mit möglichst täglicher Anwesenheit (keine wiss. Hilfskräfte)
  • Vergütung erfolgt nach HDZR-Richtlinien

Links:

Online application

Please apply online: english / german

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Materialien für Solarkraftwerke (Id 241)

Bachelor theses / Master theses / Diploma theses

Foto: solarthermisches Turmkraftwerk ©Copyright: @AbengoaTurmkraftwerke stellen die neueste Generation von Anlagen zur solarthermischen Elektroenergieerzeugung dar. Extrem konzentriertes Sonnenlicht wird dabei auf einen zentralen Absorber gerichtet, der die Wärme auf eine Wärmeträgerflüssigkeit überträgt (s. Foto). Zur Erhöhung des Wirkungsgrades von Turmkraftwerken soll die Arbeitstemperatur von derzeit maximal 550°C deutlich erhöht werden. Dafür sollen werkstoffwissenschaftliche Lösungen weiter verfolgt werden, die im Rahmen eines EU-RISE-Projektes entwickelt wurden.

Als Themen für Graduierungsarbeit werden

i) die Optimierung von optischen und elektrischen Schichteigenschaften
ii) die Verbesserung der Schichthaftung auf Hochleistungslegierungen und
iii) die Komplettierung eines neuen Schichtsystems angeboten.

Zur Charakterisierung der untersuchten Materialien stehen modernste in situ und ex situ Analysemethoden zur Verfügung.

Department: Nanocomposite Materials

Contact: Dr. Krause, Matthias

Requirements

1. Studium der Werkstoffwissenschaften, Physik oder Chemie mit überdurchschnittlichen Leistungen (Notendurchschnitt ≤ 2.0)
2. Interesse und Freude an experimenteller wissenschaftlicher Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Fachkundige Englischsprachkenntnisse

Conditions

internationale Forschungsumgebung, ortsübliche Aufwandsentschädigung

Online application

Please apply online: english / german

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