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A new ionization chamber for measuring radon concentration has been developed for an EU project in the Solid State Mechanics department at the University of Siegen. Such highly sensitive chambers require special insulation. The University of Siegen successfully collaborated with the Bad Berleburg-based company REGUPOL.

Radon is a naturally occurring gas that rises from the ground. It is odorless and colorless, but radioactive. It is therefore important to keep an eye on radon levels in the air. Ionization chambers are used to measure it. Scientists at the University of Siegen have built a new, highly sensitive radon pulse ionization chamber that will be operated as part of the EU RadonNET project. By monitoring radon concentrations in outdoor air, possible correlations with climate change are to be identified.

Until recently, the radon pulse ionization chamber was calibrated at the Physikalisch-Technische Bundesanstalt in Braunschweig. Now, according to Kerstin Weinberg, it will be permanently stationed at the University of Siegen, where it will measure the radon concentration in the air.

Prof. Dr.-Ing. Kerstin Weinberg from the Chair of Solid Mechanics explains the measurement procedure: "Air containing radon is passed through the chamber. Some of the radon decays and radiation (alpha particles) is released. This radiation leads to ionization of the air molecules inside the chamber. The resulting ions are accelerated by an electric field so that they generate a charge pulse on the electrodes of the chamber that is proportional to the energy of the alpha particles. These pulses are measured to determine the radon concentration in the ambient air." The radon pulse ionization chamber provides a sensitive method of monitoring radon exposure, which is particularly important for health and radiation protection because high radon concentrations increase the risk of lung cancer.

Soundproofing the chamber was a challenge. The Institute of Solid Mechanics worked together with the company REGUPOL from Bad Berleburg. The working group selected an elastomer damping layer from the REGUFOAM material family for the elastic mounting of the ionization chamber. These materials are otherwise used for the elastic mounting and decoupling of building services equipment, machine foundations and buildings.

A new research project at the Siegen Chair of Solid Mechanics is simulating the damping behavior of elastomer foams.

Due to their structure-dependent and therefore individually adjustable deformation behavior, foamed elastomers have a wide range of applications in various branches of industry, for example in components of sealing, thermal insulation and soundproofing systems. While computer-based design methods have given these systems an enormous development boost in the last decade during development, the requirement profiles have been continuously expanded so that today the damping properties of externally induced mechanical vibrations (structure-borne noise) are also taken into account.

In a new project at the chair of Solid Mechanics by Kerstin Weinberg from the University of Siegen, the influence of the microstructure on the dynamic material behavior of elastomer foams is now being systematically investigated. The research project of the Industriellen Gemeinschaftsforschung (IGF) is funded by Bundesministerium für Wirtschaft und Klimaschutz with 400.000 euros. In addition to the Siegen scientists, the Deutsches Institut für Kautschuktechnologie (DIK) in Hanover is also involved as a second research institution. A special feature of the IGF projects is that small and medium-sized enterprises (SME) are also directly involved in the project. This gives SME easy access to practice-oriented research and thereby strengthens the competitiveness of medium-sized companies.

The mechanical properties of a foamed elastomer depend on both, the matrix material and the microstructure. With increasing porosity, the influence of the microstructure on the mechanical deformation behavior increases. With experimental investigations on conventional elastomer samples from industry and additively manufactured foam structures, material and structural parameters can be determined and the coupled material behavior can be simulated with computer-based methods using the finite element method (FEM). For application-oriented FEM simulations with commercial software, which are widely used in the digitized component design process of SME, simple material models are required that nevertheless reflect reality. However, the industry currently lacks such practical models for elastomer foams. Two modeling approaches are being pursued as part of the project: A phenomenological approach, which is characterized by particularly low computing times and a continuum mechanical approach, which requires no further experimental effort when modifying the foam structure. At the end of the project, real component simulations from the fields of application of the participating SME will be carried out and tested experimentally using the material models developed.

• What is the Bridge Challenge about?
  

  The goal is to design and build small bridges in a competition that is as resistant to breaking as possible.

• When?
  

  On the weekend of April 9-10, 2022.

• Where?
  

  Saint-Etienne, France

• Are there any awards?
  

  Several awards will be given.

• Where can I register?
  

  Registration will open February 11, 2022 at https://www.bridge-challenge-enise.fr/

Interested students can work on the following project:
Construction and testing of a multi-wire pulse ionization chamber (VIIK) for measuring low radon concentrations.

• Further information: PEP 2022

• Contact: Ralf Nötzel

• Who can apply?
  

  Each year, three students of the Department of Mechanical Engineering at both Bachelor's and Master's level are selected to study abroad at ENISE.

• What are the requirements?
  

  The department is responsible for the selection of students. A letter of motivation and curriculum vitae in English are required for the application, as well as a certificate of study and a current overview of academic achievements.

• When is the application deadline?
  

  Students apply for studies abroad in the winter semester for the following winter semester and/or summer semester. Currently, the application deadline for stays abroad in the academic year 2022/23 is 15 December 2021. In April 2022, any remaining seats for the summer semester 2023 will be advertised on the webpage.

• What qualifications do I acquire?
  

  Students can have the courses they attend at ENISE credited to their degree programme in Siegen. In addition, students gain an insight into other cultures, perhaps learn a new language and broaden their horizons.

• How long do I stay abroad?
  

  Students can go abroad for a semester or an academic year. The winter semester at ENISE lasts from September to January, the summer semester from February to June.

• Which courses can I take?
  

  As is the case at the University of Siegen, the courses offered vary from semester to semester and must be researched independently by the students. ENISE offers its own catalogue for English-language courses.

• Further information:
  

  For information on stays abroad in general, please click here.

  Details on the application procedure can be found here.

  In this context, please also note the information for departments, which we provide here.

District Administrator Theo Melcher recently honored three successful graduates of the University of Siegen with the Olpe District Study Award. The prize for 2020 is shared by Dr. Carola Bilgen from Kirchhundem and Laura Birlenbach from Wenden, who each received a cash award of 1,000 euros for their outstanding theses. Dr. Felicitas Pielsticker from Siegen had to wait a long time for her prize, as last year's award ceremony was cancelled due to the Corona pandemic.

Dr. Carola Bilgen studied business mathematics and received her doctorate from the Chair of Solid Mechanics. In her dissertation, the Heinsberg native dealt with numerical simulations of fracture mechanics problems using phase field models. Such computer simulations can be used to predict under what conditions and in what way cracks form in materials and how they propagate. "The topic is very ambitious and theoretically extremely challenging," Prof. Dr. Weinberg praised in her review. At the same time, she says, the research on this is of great practical value to companies, for example in product development and the virtual design of machine components.

The study prize of the Olpe district, endowed with 2,000 euros, is awarded annually for outstanding, practice-oriented scientific theses at the University of Siegen. The award winners are proposed by the Commission for Research and Young Academics of the University of Siegen and selected by an independent jury.