Practical trainings, student assistants and theses

Geometric characterization of wire mesh mist eliminators (Id 358)

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

Foto: Mist eliminator in distillation columns ©Copyright: Alexander DößThermal separation processes (e.g. distillation) are key basic operations in process engineering plants. The mass transfer is thus dependent on intensive counterflow interaction between the vapor and the liquid. The resulting turbulent flow causes droplets to be torn from the liquid phase by the vapor phase. This reduces the separation efficiency (energy efficiency and product quality) of the process. Simultaneously, droplets carried over to downstream equipment lead to corrosion, polymerization or fouling and increase component maintenance requirements.
For this reason, wire mesh mist eliminators are frequently used in practice. These separate entrained droplets as they pass through the close-meshed wire mesh. Characterization of their separation efficiency, capacity and pressure drop are essential for design and application. The focus of the work is the experimental determination and mathematical description of the pressure drop for knitted wire mesh separators as a function of their geometric properties.

Department: Experimental Thermal Fluid Dynamics

Contact: Döß, Alexander

Requirements

  • Background in process engineering, chemical engineering, mechanical engineering or related disciplines.
  • Interest in experimental work
  • Independent and result-oriented working
  • Safe handling of MS Office software
  • Confident knowledge of German or English language

Conditions

  • Work in a multidisciplinary team
  • Remuneration according to HZDR-internal tariff
  • Scientific excellence and extensive opportunities for professional networking
  • Start from November 2022 or earlier

Online application

Please apply online: english / german

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Influence of ionomer content on development of separation processes for recycling of water electrolyzers (Id 354)

Bachelor theses / Master theses / Diploma theses

Green hydrogen can be produced by water electrolysis technology, which needs critical raw materials such as platinum and iridium in their cells. Since many countries including Germany target a large scale of green hydrogen production, the development of recycling processes of the component is important for a functional circular economy. Especially development of fine particle separation processes is necessary to reach over 90 % of the recovery.
Among three types of water electrolyzer, the used materials in polymer electrolyte membrane(PEM) have different hydrophobic characteristics. Anodic electrode materials including membrane have hydrophilic surfaces and the materials on the cathode show hydrophobic characteristics. Hence, particles from the water electrolyzer can be separated by their hydrophobicity contrast. However, an ionomer is used as a binder material in the catalysts ink, which consists of a hydrophobic chain and a chain with a hydrophilic sulfonic acid group at the end. The content of the ionomer and the particles might affect their hydrophobicity and it will play an important role in the further development of separation processes. The influence of the ratio of ionomer on carbon support has been studied in terms of morphology and electrochemistry performance but not on their surface properties. The purpose of this work is to investigate the influence of different ionomer contents on the wetting behavior of the components.
In this study, particles with six different ionomer contents from 15 to 40 % will be prepared. Their surface properties can be measured by using analytic particle solvent extraction(APSE), bubble attachment test, and selective agglomeration test with the hydrophobic binder.

Department: Processing

Contact: Dr. Rudolph, Martin, Dr. Mütze, Thomas, Ahn, Sohyun

Requirements

Field of study: process engineering, chemical engineering, or a related field
Good communication skills in English
Interest in experimental work
Enjoy scientific and independent work

Conditions

Place of work: Freiberg
Start is possible immediately by agreement
Duration according to the respective study regulations
Scientific excellence and extensive professional networking opportunities.

Online application

Please apply online: english / german

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Entwicklung von Radiotracern zur Bildgebung von Tumorerkrankungen (Id 338)

Bachelor theses / Master theses / Diploma theses / Compulsory internship

Foto: macropa-Chelator mit schematischer möglicher Anwendung zur Tumordiagnostik ©Copyright: FWPDie gezielte Behandlung von Tumorerkrankungen erlangt zunehmend an Bedeutung. Die eng mit der radiopharmazeutischen Forschung verknüpfte Nuklearmedizin ist auf die Anwendung radiomarkierter Verbindungen (Radiopharmaka) für die Tumordiagnostik und -therapie spezialisiert. Dabei wird ein bestimmtes Radionuklid entweder direkt am Molekül oder stabil in einem Komplexbildner gebunden und an ein biologisch aktives Molekül geknüpft (Peptid, Antikörper...). Das Radiopharmakon bindet dann spezifisch an bestimmten Zellen (z. B. Knochenzellen, Tumorzellen...). Während zur diagnostischen Bildgebung Gamma- und Positronenemitter eingesetzt werden, kommen für therapeutische Anwendungen ausschließlich Betaemitter und Alphaemitter zum Einsatz. Für den Alphaemitter Actinium-225 steht, sofern der Chelator macropa verwendet wird, gegenwärtig kein geeignetes diagnostisches Radionuklid zur Verfügung.

In diesem Forschungsprojekt sollen Konjugate hergestellt werden, welche mit einem bildgebenden Radionuklid (Fluor-18, Iod-123, Lanthan-133) radiomarkiert werden können. Die Konjugate sollen sich gleichermaßen für die stabile Bindung von Actinium-225, welches therapeutisch angewendet wird, eignen. Nach erfolgreicher Synthese und Charakterisierung von definierten Zielverbindungen sollen diese radiomarkiert, und die Stabilität der radiomarkierten Substanzen im biologischen System beurteilt werden. Die vielversprechendsten Konjugate sollen anschließend auf zellulärer Ebene und schlussendlich präklinisch in vivo evaluiert werden.

Department: Radionuclide Theragnostics

Contact: Dr. Reissig, Falco, Dr. habil. Mamat, Constantin

Requirements

  • Studium der Chemie oder eines artverwandten Studiengangs
  • Erfahrungen im Bereich der Synthesechemie und Analytik
  • Interesse an der wissenschaftlichen Arbeit in einem interdisziplinären Team
  • Bereitschaft zum Umgang mit Radioaktivität

Conditions

  • Beginn ist nach Absprache ab sofort möglich
  • Praktikumsdauer mindestens 8 Wochen
  • Vergütung nach internen HZDR-Regelungen

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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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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