Practical trainings, student assistants and theses

Platinum group metals (PGMs), particularly rhodium (Rh), palladium (Pd), and platinum (Pt), are regarded as the "vitamins" used in the modern industry. PGMs are crucial components of fuel cells, jewelry, computers, cell phones, automobile catalysts, etc. Their distinct physical and chemical characteristics, such as their corrosion resistance, chemical inertia, and catalytic activity, account for their extensive application and create alloys to enhance the characteristics of other transition metals. Because of their unique properties, PGMs are seldom replaced with other elements or compounds in applications. However, PGM deposits in the earth's crust are limited. The utilization of secondary resources, such as recycling waste materials, could mitigate the issue of PGM scarcity. Several conventional methods have been used for recovering PGM from secondary sources. Among the separation technologies, membrane separation offers the continuous and selective recovery of individual PGMs with no adverse environmental effects.
Supported liquid membranes (SLM) are a chemically driven membrane method in which a solvent phase contains an organic ligand that preferentially binds to a metal in the feed solution. The metal-ligand combination is subsequently diffusively carried across the membrane support and discharged into the receiving phase. This approach is particularly useful for metal ion separation because the organic carrier generates lipophilic metal-organic ligand complexes. This continuous permeation technique combines extraction and stripping procedures with less chemical reagents. The objective of the thesis work deals with the employment of task-specific organic ligands as carriers in the supported liquid membrane system for the selective recovery of platinum group metals from secondary source leachates and understanding the transport mechanism using different mathematical modeling approaches.

• Conduct literature research on supported liquid membranes using various organic carriers and their applications in metal recovery
• Design and conduct laboratory experiments using supported liquid membrane studies using task-specific organic carriers with several parameters such as pH, concentration, the thickness of membrane, feed solutions, etc.
• Analyse and interpret data on membrane selectivity, flux rates, fouling resistance, and metal recovery efficiency
• Optimize experimental conditions targeting high recovery rates for Platinum, Palladium, and Rhodium
• Prepare a thesis report and present findings at conferences or workshops

• Bachelor's degree in Chemistry, Chemical Engineering, Environmental Engineering or related field
• Knowledge of hydrometallurgical processes and membrane separation technologies
• Knowledge of analytical techniques such as ICP-OES, AAS, or similar for metal concentration analysis
• Duration: 6 months
• Start Date: Start in 2025 is possible
• Funding: Remuneration according to HZDR internal regulations

Understanding the behaviour of fibre-laden drops is critical due to their presence in various industrial applications, including microelectronics fabrication, portable medical devices, and biofuel production. Our work focuses on the numerical simulation of fibre-laden drops, specifically investigating a single long deformable fibre within a drop impacting a solid substrate. The study aims to elucidate the dynamic interactions between the fibre and the drop. Key objectives include determining the changes in drop dynamics due to the fibre and observing fibre deformation upon impact.

This work will involve computational fluid dynamics (CFD), particularly finite volume methods, with a focus on interface tracking using the Volume of Fluid approach. The simulation will incorporate surface wettability to enhance our understanding of elasto-capillary interactions, offering insights relevant to real-world applications.

We are seeking a motivated student with prior experience in CFD (preferably OpenFOAM) or similar modelling software.

• Enrolled in a degree program such as Process Engineering, Mechanical Engineering, or Computational Modelling and Simulation
• Strong interest in particle-fluid dynamics and numerical simulations
• Preliminary experience in CFD, ideally with OpenFOAM
• Basic coding skills, preferably in C++

• Immediate start possible
• Duration of internship or thesis as per university regulations
• Remuneration available, scholarship holders (e.g. ERASMUS+) are welcome

Flowing foam is relevant to many different industrial applications, such as froth flotation in mineral processing, fire-extinguishing systems, or brewing beer and beverage production. In a scientific context, the rheological properties of foams are very complex and significantly different from those of Newtonian fluids such as water. As a result, despite numerous experimental and theoretical studies, the fluid dynamics of foams remain poorly understood.

This project focuses on a classical benchmark experiment: the flow around a cylindrical obstacle. To identify key parameters of flowing foam in this configuration, we use two unique radiographic measurement techniques. First, neutron radiography provides imaging measurements of the local liquid fraction of the flowing foam. Second, X-ray radiography with foam-tailored tracer particles allows to perform local velocity measurements in the flowing foam.

The following subtasks are mainly to be worked on:

• Assistance in preparing and performing the foam flow experiment in the X-ray laboratory at HZDR
• Analysis of the measurement data, including image processing and machine learning if applicable
• Documentation of the experiment and measurement results in written form

• Field of study: process engineering, fluid mechanics, or similar focus in chemistry or physics
• Experience with laboratory work, imaging measurement techniques or measurement data analysis is beneficial (e.g. using ImageJ, Matlab, Python)
• High motivation and interest in the subject
• Careful, structured and independent way of working
• Good oral and written communication skills in English or German
• Enjoyment of scientific work

• Working in a multi-disciplinary and international team
• Place of work: HZDR or TU Dresden
• Start: from January 2025
• Duration: min. 3 months
• Remuneration according to HZDR internal regulations

The application of phage surface display (PSD) technology has accelerated developments in the field of biomolecular sensors and materials science. A practical complement to this technology is Next-Generation Sequencing (NGS). In this combination, a more comprehensive view of biopanning rounds with a deep insight into the entire sequence space is made possible. It is possible to identify sequencing artefacts, determine sequence number and structure, recognize binding motifs and observe the evolution of the phage library over the course of an experiment. PSD in combination with biopanning is able to select candidates with high affinity and selectivity to the desired substrates from large peptide libraries. In practice, this specific enrichment of peptides leads to a reduction in library diversity. It should therefore be possible to better visualize this reduction in sequence space using data clustering methods in order to better understand distances between similar sequence families.
The student's task is to find suitable clustering methods for sequencing results from multiple phage display experiments and to apply these if necessary. It should be clear from the results to what extent the sequence space can be grouped into families and whether a mutation profile within and between these families is recognizable.

Prerequisite is a valid enrollment in a Master's program in bioinformatics, biotechnology, molecular biology, biochemistry, biology or a related natural science program. Furthermore:

• Interest in data cluster methods and bioinformatics
• Basic knowledge of bioinformatics, statistics, stochastics and clustering
• Experience with a programming language (e.g. Python, R, C, C++ or other)
• Ability to work independently and in a team

The topic is to be worked on as part of a Master's thesis in conjunction with a voluntary or mandatory internship. This results in a duration of 12 months. The duration can be extended or adjusted in consultation with the supervisor. We can offer you:

• An innovative multidisciplinary research environment related to relevant issues in resource technology
• Supervision by experienced scientists
• Practical experience in the field of bioinformatics and directed evolution

The research project ‘Development of tailor-made peptides for the treatment of polymers before the metallization of plastics’ aims to develop a biomolecule-based system that enables the metallization of high-quality engineering plastics. Using phage surface display technology (PSD), peptides are selected and their binding behavior is characterized using suitable technologies to quantify the surface interaction. Our industrial partner tests suitable peptide sequences in practical polymer coating and metallization experiments.

• Studying biotechnology, microbiology, chemistry, chemical engineering, or a comparable subject area
• Interest in practical, interdisciplinary research
• Knowledge of basic molecular biological and microbiological principles and working techniques
• Careful and independent way of working

• Work in an interdisciplinary and international team
• The workplace language is English
• Duration of the internship or thesis according to study regulations
• Start of work possible by February 2025 at the latest

The development of a multi-channel flow body sensor according to patent WO 2010/069307 A1 aims to quantify the gas content in flow-carrying components. A decisive advantage of this sensor lies in its optical measuring principle, which is based on fiber-optic coupling and the analysis of the light output signal. This avoids electrical potentials in the measuring area, offering significant advantages over electrical measuring methods (intrinsic safety), especially for explosive mixtures.

Preliminary tests at the Institute for Experimental Fluid Dynamics at the Helmholtz Center Dresden-Rossendorf on gas-liquid flows showed that a clear binarization of the sensor output signal can be achieved due to the capillary effects in narrow channels and the different refractive indices of the gas and liquid phases. Building on previous work with a single-channel sensor prototype based on a polymer optical fiber (POF) with a diameter of 1 mm, the following tasks must be completed as part of further research.

Tasks:

• Adjusting the POF diameter to 1.5 mm in the single-channel configuration.
• Conducting experimental investigations of the new single-channel prototype using the already developed test system and evaluation programs.
• Designing a multi-channel sensor body for gas content measurements in the system.
• Developing a transition adapter to optimize the flow distribution between the DN10 flow pipe and the sensor body.

• Students majoring in fields such as process engineering, mechanical engineering, or chemical engineering.
• Interest in fluid mechanics and the development of measurement technology.
• Experience with 3D CAD tools.
• Basic knowledge of Python programming

Start date: 01.01.2025
Duration: according to the respective study regulations

Background:

Currently, there is a broad discussion whether ventilation by frequent window opening is sufficient for providing a sufficient amount of fresh air or if technical air purification devices based on e.g. HEPA filters are better solutions for public spaces. Furthermore, there is another discussion ongoing, whether a well-guided laminar flow or a high degree of mixing within a room is more beneficial. The latter, on the one hand distributes the potentially virus-laden aerosols in the whole room, but on the other hand reduces the peak concentrations of these aerosols clouds by magnitudes.

Objectives:

The objective is to perform aerosol propagation experiments and to estimate the potential aerosol inhalation of people in dynamic situations. To achieve this, an aerosol generator will be used in a demonstrator room under different flow conditions. The data from different scenarios will be processed in order to obtain a transference function that can relate the aerosol source with the aerosol receivers.

Tasks:

• Literature survey
• Aerosol experiments in different scenarios.
• Post-processing of the results.

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

Duration:

4-6 months

Remuneration:

According to HDZR guidelines