Practical trainings, student assistants and theses

Chemical reactions fronts and instabilities comprise fields of research that constantly call for new challenges. Present in numerous technological applications (porous media, reactive mass transfer, CO2 capturing) they present diverse challenges. The potential intern/diplomand will be asked conduct experiments where a Xanthan Gum dispersion is injected into a surfactant (C14TAB) solution which is already inside a thin gap (Hele-Shaw cell) reactor. In this process, a weak gel membrane is formed by physicochemical interaction and a viscous instability emerges.

The candidate is expected to:

• Conduct experiments in the lab, using different chemical (e.g. concentrations) and hydrodynamic parameters (e.g. flow rate, flow cell).
• Image post-processing of the results and data analysis.

References
[1] Keshavarzi et al. (2019) Langmuir 35(42) 13624-13635
[2] Riolfo et al. (2012) Phys Rev E 85 015304

• Study in Process Engineering, Chemical Engineering, Mechanical Engineering (or relative field)
• Basic fluid dynamics and transport phenomena knowledge
• Experience in image post-processing is preferred but not obligatory (i.e. using ImageJ, MATLAB, Python)
• Motivation, interest in the field, ability to solve problems, good academic track records

• Duration min. 6 month, start: Feb/Mar 2023, workplace: TU Dresden

• Student (w/m/d) der Betriebswirtschaft, der Wirtschafts- und Ingenieurwissenschaften, der Informatik oder anderes Studium
• Interesse an der Durchführung von Beschaffungen als öffentlicher Auftraggeber
• Freude an der Kommunikation im Team, mit Wissenschaftlern und Lieferanten/Dienstleistern (w/m/d)
• Deutsch- und Englischkenntnisse, gern auch weitere Fremdsprachen
• Bis zu 19 Stunden pro Woche, mit der Möglichkeit der freien Zeiteinteilung (flexible, aber anteilige Verteilung)
• Beginn ab sofort

• Eine flexible Tätigkeit mit guter Bezahlung bei einem attraktiven Arbeitgeber
• Freude bei der Arbeit in einem innovativen "Einkaufs-Team"
• Erwerb und Vertiefung:

• Arbeitsort HZDR, Standort Rossendorf
• Bei Eignung und Interesse bieten wir eine längerfristige Perspektive mit einem interessanten Aufgabenspektrum.

Die Zentralabteilung Forschungstechnik entwickelt spezialisierte Forschungsausrüstung für die Institute des HZDR. Die dazu entwickelte Software unterliegt unterschiedlichen und sehr individuellen Anforderungen. Du unterstützt uns dabei mit den von dir entwickelten Tools Abläufe zu automatisieren und Entwicklungsprozesse zu vereinfachen.

Das erwartet dich:

• Du entwickelst Software Lösungen zur Verbesserung der Entwickler-Workflows unter Nutzung der GitLab API/SDK
• Du erarbeitest Konzepte und setzt sie in Code um
• Du nutzt und verbesserst Continuous Integration und Deployment Pipelines

Dein Profil:

• Student (w/m/d) Informatik oder vergleichbares Studium
• (Sehr) gute Kenntnisse mindestens einer relevanten Programmiersprache, z. B. Python, C++
• Sehr gute Kenntnisse der Versionsverwaltung mit Git
• Vorteilhaft sind Kenntnisse im Umgang mit Gitlab CI und Docker

• Beginn ab sofort möglich
• Bis zu 19 Stunden pro Woche
• Dauer zwischen 2 und 5 Monaten
• Arbeitsort HZDR, Standort Rossendorf

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

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.

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.

Mit Spitzenforschung in den Bereichen ENERGIE, GESUNDHEIT und MATERIE lösen wir am Helmholtz-Zentrum Dresden-Rossendorf (HZDR) einige der drängenden gesellschaftlichen Herausforderungen unserer Zeit. Das Görlitzer Center for Advanced Systems Understanding (CASUS) ist ein weltweit einzigartiges Zentrum für datenintensive Forschung im Bereich digitaler Systeme. Die deutsch-polnische Einrichtung wurde 2019 gegründet und betreibt interdisziplinäre Systemforschung in unterschiedlichen Bereichen wie Erdsystemforschung, Systembiologie und Materialforschung.

Das HZDR Center for Advanced Systems Understanding (CASUS) sucht ab sofort Studierende, die das Feld des Reisekostenmanagement und Verwaltung in einem öffentlichen Sektor kennenlernen und erste Erfahrungen in einem internationalen Umfeld sammeln möchten. Als SHK bist Du zuständig für die Organisation von Reisen und Unterstützung bei deren Durchführung und Abrechnung, sowie Unterstützung der administrativen Verwaltung in Görlitz bei unterschiedlichen Angelegenheiten, Aufgaben und Projekten.

Wir bieten:

■ Einen flexiblen Job mit guter Bezahlung, der sich auch noch gut im Lebenslauf macht
■ Freude bei der Arbeit in einem internationalen Team
■ Erfahrungen:
- bei der Vermittlung von Wissen sowie Softskills
- in der Arbeit mit Verwaltungssysteme wie SAP
- in der Arbeit mit Reisekostenabrechnungssystemen
- organisatorische Fähigkeiten, die bei Prüfungen, Bewerbungen und dem späteren Job helfen
■ Auf Wunsch eine längerfristige Perspektive mit einem Aufgabenspektrum, das mit der Zeit immer vielfältiger wird und zunehmend auch eigenverantwortliche Projekte enthält

■ Freude am Organisieren und an der Kommunikation im Team, mit Wissenschaftlern, Dienstleistern sowie mit unterschiedlichen Zielgruppen
■ Deutsch- und Englischkenntnisse
■ 19 Stunden pro Woche die Möglichkeit zum Arbeiten (flexible, aber anteilige Verteilung)

Der Arbeitsbeginn soll nach Abstimmung relativ kurzfristig erfolgen.

Weiterführende Informationen können jederzeit gern erfragt werden bei:

Weronika Mazur | CASUS International Office
Philipp von Haymerle | CASUS Project Manager

Tel.: +49 3581 37523 23 | E-Mail: w.mazur@hzdr.de;
+49 3581 37523 21 | E-Mail p.haymerle@hzdr.de

CASUS – Center for Advanced Systems Understanding am HZDR
Untermarkt 20 | D-02826 Görlitz
www.casus.science

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

• 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

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

The separation of aerosol particles by a moving gas-liquid fluidic interface is central to a wide variety of industrial and natural applications, among which stand out air purification systems and precipitation scavenging. The particle size significantly affects the separation rate. The diffusion of particles in the nanometer range is largely dominated by molecular diffusion. In this regime, predictive models accurately estimate the separation rates. Model inaccuracy increases, however, significantly when the particle size ranges from 0.1 μm to 2.5 μm. In this impaction-dominated regime, the complex interplay between the flow dynamics on both sides of the fluidic interface and the particle inertia makes it difficult to develop suitable models.
In this work, the student will numerically investigate whether enforcing bubble deformation into a non-spherical shape leads to a higher deposition rate, hereby making the particle separation process more efficient. The results will lead to the development of an improved and reliable separation model accounting for the deformation of the fluidic interface and the associated flow changes.

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

• Either an immediate start or a start in 2022 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

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 energy, health and matter. The Institute of Fluid Dynamics is conducting basic and applied research in the fields of thermo-fluid dynamics and magnetohydrodynamics in order to improve the sustainability, the energy efficiency and the safety of industrial processes.

Multiphase flows are important part of many industrial applications, whereas modelling of them is a challenging and complex task. For flow situations with higher void fractions, HZDR developed a new generalized concept for the CFD-simulations including flow regime transitions. The GENTOP (Generalized Two-Phase Flow) approach is able to simulate co-existing large-scaled (continuous) and small-scaled (polydispersed) structures (Fig. 1). Previous results were performed with the CFD code CFX and compared against DEBORA validation data.

The goal of the thesis would be to apply and improving the existing state of the simulations in the Fluent GENTOP framework.

We offer an interesting task dealing with complex physical phenomena, work in an international team using state-of-the-art calculation and programming methods.

We are looking for a motivated student (f/m/d) (master thesis) able to perform CFD simulations, understand and program code to generalize/parametrize CFD simulations, work with experimental data sets, document and present the work in an appropriate manner. Useful but not required is a knowledge of the following software tools: CFD codes CFX and Fluent, Python, GIT.

The task is supervised by Framatome and HZDR.

FRAMATOME is a designer and supplier of nuclear steam supply system and nuclear equipment, services and fuel for high levels of safety and performance. Framatome is a major international player in the nuclear energy market recognized for its innovative solutions and value-added technologies for designing, building, maintaining, and advancing the global nuclear fleet. The company designs, manufactures, and installs components, fuel and instrumentation and control systems for nuclear power plants and offers a full range of reactor services. With 14,000 employees worldwide, every day Framatome's expertise helps its customers improve the safety and performance of their nuclear plants and achieve their economic and societal goals.

• Studies in Engineering, Computer Science or comparable
• Interest in numerical work
• Good communication skills in both written and spoken English
• Useful but not required is a knowledge of the following software tools: CFD codes CFX and Fluent, Python, GIT.

• A vibrant research community in an open, diverse, and international work environment.
• Scientific excellence and extensive professional networking opportunities.
• Compensation as student researcher (working hours to be determined).
• Working place will be Dresden and/or Erlangen Germany.

Various 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.

-- 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

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

Various 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.

-- 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

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

Various 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.

-- 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

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

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.

-- 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

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

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 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

• 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)

• 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)

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

• 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

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

Liquid 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.

• 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

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

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.

• 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

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

Turmkraftwerke 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.

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

internationale Forschungsumgebung, ortsübliche Aufwandsentschädigung