TY - JOUR A1 - Spitzer, Stefan A1 - Abed, Arkan A1 - Seifert, Alexander A1 - Salzano, Ernesto T1 - Risks from Hydrogen Carriers - Safety Characteristics of the LOHC System Toluene/Methylcyclohexane N2 - Reversible liquid organic hydrogen carriers (LOHCs) seem to be a promising solution for the transportation of hydrogen. Since no pressure or cooling needs to be applied during the transport, it is considered easier, safer and cheaper compared to pressurized gas tanks or cryogenic hydrogen on long routes and is already applied in large quantities and long distances. One simple system is methylcyclohexane and toluene. Toluene gets shipped to countries with an excess of (preferably green) energy and is charged with hydrogen to form methylcyclohexane. This is then shipped back to the place with energy and/or hydrogen demand and split into hydrogen and toluene. For toluene, some safety characteristics are available, whereas methylcyclohexane is loosely analyzed, hence safety characteristics are the basis for an appropriate approach to tackle the hazards and for the risk assessment. This paper focuses on the safety characteristics of both substances, compares the differences and points out the crucial hazards of this system, especially if the same tanks for transportation are used. T2 - 18th EFCE International Symposium on Loss Prevention and Safety Promotion in the Process Industries CY - Bologna, Italy DA - 08.06.2025 KW - Explosion protection KW - Rate of pressure rise KW - Hydrogen transport PY - 2025 DO - https://doi.org/10.3303/CET25116058 SN - 2283-9216 VL - 116 SP - 343 EP - 348 PB - AIDIC Servizi S.r.l. CY - Italy AN - OPUS4-63734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin T1 - Introduction of numerical methods to simulate damage accumulations of composite pressure vessel N2 - The development of hydrogen as a reliable energy sector is strongly connected to the performance and the level of safety of hydrogen storage system. Composite damage due to static, fatigue loading and ageing effect is a progressive process. The common failure modes of composite pressure vessels are majorly fibre break, then interface debonding, matrix cracking and delamination. The damages occur subsequently or even simultaneously, failure modes may interactive each other. These attributes make the composite fatigue more complex and difficult. The presentation here is to show how the numerical methods being developed to match this challenge, particularly the numerical model of composite pressure vessel developed by FibreMod research project is introduced. The potential role of numerical simulation in the certification process and the outlook for the further trend is also discussed. T2 - Abteilungskolloquium CY - BAM Berlin, Germany DA - 10.05.19 KW - Fibre Break KW - Composite Pressure KW - Vessels KW - Simulation PY - 2019 AN - OPUS4-48302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dayani, Shahabeddin T1 - Quantification of Deep Discharge Mechanism in a Li-Ion Battery by operando X-ray Computed Tomography N2 - Lithium-ion batteries connected in series are prone to an electrical abuse called over discharge. We present a comprehensive investigation of the over discharge abuse mechanism in lithium-ion batteries using operando non-destructive imaging. The study focuses on understanding the behavior of copper dissolution and deposition during over discharge, which can lead to irreversible capacity loss and internal short circuits. By utilizing synchrotron X-ray computed tomography (SXCT), the concentration of dissolved and deposited copper per surface area is quantified as a function of depth of discharge (DoD). T2 - HZB user meeting CY - Berlin, Germany DA - 22.06.2023 KW - Non-destructive testing PY - 2023 AN - OPUS4-57793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - Synchrotron X-Ray Tomography Techniques at BAMline N2 - A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and operando studies can now be routinely performed, and different energy spectra can easily be set up. In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired. T2 - HZB User Meeting CY - Online meeting DA - 08.12.2022 KW - BAMline KW - X-ray imaging KW - Tomography PY - 2022 AN - OPUS4-56568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, H A1 - Paulisch, M C A1 - Gebhard, M A1 - Osiewacz, J A1 - Kutter, M A1 - Hilger, A A1 - Arlt, T A1 - Kardjilov, N A1 - Ellendorff, B A1 - Beckmann, F A1 - Markötter, Henning A1 - Luik, M A1 - Turek, T A1 - Manke, I A1 - Roth, C T1 - Development of a Modular Operando Cell for X-ray Imaging of Strongly Absorbing Silver-Based Gas Diffusion Electrodes N2 - Metal-based gas diffusion electrodes are utilized in chlor-alkali electrolysis or electrochemical reduction of carbon dioxide, allowing the reaction to proceed at high current densities. In contrast to planar electrodes and predominantly 2D designs, the industrially required high current densities can be achieved by intense contact between the gas and liquid phase with the catalytically active surfaces. An essential asset for the knowledge-based design of tailored electrodes is therefore in-depth information on electrolyte distribution and intrusion into the electrode’s porous structure. Lab-based and synchrotron radiography allow for monitoring this process operando. Herein, we describe the development of a cell design that can be modularly adapted and successfully used to monitor both the oxygen reduction reaction and the electrochemical reduction of CO2 as exemplary and currently very relevant examples of gas-liquid reactions by only minor modifications to the cell set-up. With the reported cell design, we were able to observe the electrolyte distribution within the gas diffusion electrode during cell operation in realistic conditions. KW - X-Ray imaging KW - Gas diffusion electrodes KW - Operando cell PY - 2022 DO - https://doi.org/10.1149/1945-7111/ac6220 VL - 169 IS - 4 SP - 044508 PB - IOP science AN - OPUS4-55027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra T1 - Accumulation of fibre breaks in racetrack specimens and type IV pressure vessels N2 - The reduced volume method has been studied using the fibre break model from Mines ParisTech. This method allows less 3D finite elements to be used for predicting the failure of real scale composite structures. A favourable comparison results with racetrack specimens has been achieved. However, the comparison study with a type IV pressure vessels still requires more Evaluation. T2 - Consortium Meeting FiBreMoD CY - Toyota Motor Europe, Belgium DA - 27.03.2019 KW - Reduced volume method KW - Integral range KW - Multiscale model KW - Fibre break KW - Composite pressure vessels KW - Racetrack specimens PY - 2019 AN - OPUS4-48571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Optimization of Solid-State-Reactions of Calcium Cobaltite Ca3Co4O9 N2 - Calcium cobaltite is a promising p-type oxide thermoelectric material for high temperature applications due to its high figure of merit between 600 °C and 900 °C in air. The solid-state-reaction is well known for large scale powder synthesis of functional materials. As a high temperature process, the powder synthesis consumes a lot of energy. In different studies, different synthesis conditions were used for the preparation of calcium cobaltite powder. This study showed that a higher energy input (elevated temperatures, longer dwell times, or repeated calcinations) during powder synthesis does not increase but decrease the Seebeck coefficient and the electrical conductivity. The same correlation was determined for the densification. As a higher energy input leads to a larger grain size and therefore to a reduced sinter activity, it can be concluded that the thermoelectric properties are correlated with the sinter activity of the powder. These results can be used to minimize the energy demand for the powder synthesis of Ca₃Co₄ O₉. T2 - 14th European Conference on Thermoelectrics CY - Lisbon, Portugal DA - 20.09.2016 KW - Thermoelectrics KW - Solid-State-Reaction KW - Calcium cobaltite PY - 2016 AN - OPUS4-37543 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Sintering and interconnecting thermoelectric oxides for energy applications N2 - Today, more than 12% of the primary energy is lost in the form of waste heat. Thermoelectric generators (TEGs) can convert waste heat directly into electrical power by utilizing the Seebeck effect. The performance of such a generator is defined by a dimensionless figure of merit ZT of the thermoelectric pairs and the resistance R of the metallic contacts between these pairs. The figure of merit of thermoelectric oxides is considerably smaller compared to semiconductors. Still, thermoelectric oxides like calcium cobaltite (Ca3Co4O9) are attractive for applications at elevated temperatures in air. In contrast to the established π-type architecture of common TEGs, tape casting and multilayer technology may be applied for cost-effective manufacturing of oxide TEGs. Promising demonstrations of multilayer TEGs have been published in the last years. Still, the development of reliable and scalable manufacturing processes and proper material combinations is necessary. The aim of our project is to evaluate the feasibility of low temperature co-fired ceramics (LTCC) technology for a practical manufacturing of oxide multilayer TEGs of Ca3Co4O9 (p-type) and calcium manganate (CaMnO3, n-type). Ca3Co4O9 exhibits an undesired phase decomposition at 926 °C. Because of that, the application of sintering strategies and interconnect concepts well known from LTCC technology is a promising approach. We present results of pressure-assisted sintering of Ca3Co4O9 multilayer at 900 °C and axial pressures of up to 7.5 MPa. Ca3Co4O9 was produced by solid state reaction of CaCO3 and cobalt(II,III)oxide at 900 °C. Green tapes were prepared by a doctor-blade process, manually stacked and laminated by uniaxial thermocompression. Sintering was conducted in a LTCC sintering press between SiC setter plates. The thickness shrinkage was recorded by an in-situ technique. After sintering under 7.5 MPa, the microstructure of the single phase material shows a high density of 95 % and an advantageous alignment of the platelet grains. This results in good electrical conductivity and a comparatively high ZT of 0.018 at room temperature. However, the lowering of CaMnO3 sintering temperature from above 1200 °C to below 920 °C remains a challenge. To select a proper metal paste for interconnections of an oxide TEG, several pastes have been investigated regarding contact resistance of internal and external (soldered) connections in a preliminary study. Commercial pastes containing Ag, Au, Au/Pt, Ag/Pd, and Ag/Pd/Bi were manually applied and post-fired on sintered test bars of Ca3Co4O9 and CaMnO3 at 900 °C for 2 h. All tested pastes formed mechanically stable metallization after firing. For resistance measurement, 4-wire method and a custom-made probe head were used. The contacts on Ca3Co4O9 exhibit significantly (2-sample t-test, α = 5%) higher resistance compared to contacts on CaMnO3. Pure silver paste exhibits the lowest resistance for internal contacts on both materials, lower than 5 mΩ on CaMnO3. Ag/Pd/Bi paste resulted in conspicuously high variance of resistance. EDX analyses clarified an enrichment of Bi in the thermoelectric material near the interface and thereby the formation of an oxide layer with probably high electrical resistance. The thickness of that layer varies with the thickness of metallization. In conclusion, the use of Bi containing pastes is not advisable. Pure Ag paste shows the best results regarding resistance and solderability. T2 - CICMT 2018 CY - Aveiro, Portugal DA - 18.04.2018 KW - Thermoelectric oxide KW - Thermoelectric generator KW - Multilayer technology KW - Pressure-assisted sintering PY - 2018 AN - OPUS4-44740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Lowering the sintering temperature of calcium manganate CaMnO3 for thermoelectric applications N2 - Thermoelectric materials can convert waste heat directly into electrical power by utilizing the Seebeck effect. Calcium cobaltite (p-type) and calcium manganate (n-type) are two of the most promising oxide thermoelectric materials. The development of cost-effective multilayer thermoelectric generators requires the co-firing of these materials and therefore the adjustment of sintering temperatures. Calcium manganate is conventionally sintered between 1200 °C and 1350 °C. Calcium cobaltite exhibits an undesired phase transition at 926 °C but can be sintered to high relative density of 95 % at 900 °C under axial pressure of 7.5 MPa. Hence, co-firing at 900 °C would be favourable. Therefore, strategies for lowering the sintering temperature of calcium manganate have been investigated. Basically, two approaches are common: i) addition of low melting additives like Bi2O3-ZnO-B2O3-SiO2 (BBSZ) glass or Bi2O3, and ii) addition of additives that form low-melting eutectics with the base material, for example CuO. In this study, several low melting additives including BBSZ glass and Bi2O3, as well as CuO were tested regarding their effect on calcium manganate densification. Bi2O3 did not improve the densification, whereas BBSZ glass led to 10 % higher relative density at 1200 °C. An addition of 4 wt% CuO decreases the temperature of maximum sinter rate from above 1200 °C to 1040 °C. By reducing the particle size of the raw materials from 2 μm to 0.7 μm the maximum sinter rate could be further shifted 20 K towards lower temperatures and the sinter begin decreased from 920 °C to 740 °C. It is shown that eutectic phase formation is more effective in lowering sintering temperature and accelerating densification than low-melting additives. T2 - 93. DKG-Jahrestagung und Symposium Hochleistungskeramik 2018 CY - Munich, Germany DA - 10.04.2018 KW - Thermoelectrics KW - Sinter additive PY - 2018 AN - OPUS4-44818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Eine sichere Zukunft für Lithium-Ionen Batterien N2 - Eine sichere Zukunft hat eine Technologie dann, wenn sie die Gesellschaft auch von ihrer Sicherheit überzeugen kann. Dies ist insbesondere für Lithiumbatterien von hoher Bedeutung. Die BAM trägt auf den verschiedene Ebenen auf vielfältige Art und Weise dazu bei, diese Sicherheit zu untersuchen und zu verbessern. T2 - 4. Batterieforum Berlin Brandenburg CY - Potsdam, Germany DA - 22.11.2024 KW - LIthiumbatterien KW - Sicherheit PY - 2024 AN - OPUS4-62328 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra T1 - Accumulation of Fibre Breaks under Time Dependent Loads in CFRP Materials of Pressure Vessels N2 - BAM has discovered that the reliability of tested composite pressure vessel will be altered when the loading speed is varied. The ageing of composite materials in general gives negative effect to the structure, however there might be positive effect occurs due to the load redistribution between the fibres. The study on the negative effect of ageing has been compared favourably with the fibre break model from Mines ParisTech. To improve the model's capability, this positive effect should also be implemented. The problem however to evaluate real scale model that might take extensive computation time. The reduced volume method then was proposed to improve the calculation time. The next study is then to check the approach on different loading condition and compare the result with experimental data provided by BAM. T2 - PhD Day 2018 CY - Evry, France DA - 20.06.2018 KW - Fibre Break Accumulation KW - Carbon Fibre Pressure Vessels KW - Time Effect KW - Integral Range PY - 2018 AN - OPUS4-45567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Farhan, Muhammad A1 - Schneider, Ronald A1 - Thöns, Sebastian A1 - Gündel, M. T1 - Probabilistic cost modeling as a basis for optimizing inspection and maintenance of turbine support structures in offshore wind farms N2 - The operational management of offshore wind farms includes inspection and maintenance (I&M) of the wind turbine support structures. These activities are complex and influenced by numerous uncertain factors that affect their costs. The uncertainty in the I&M costs should be considered in decision value analyses performed to optimize I&M strategies for the turbine support structures. In this paper, we formulate a probabilistic parametric model to describe I&M costs for the common case in which a wind farm is serviced and maintained using a workboat-based strategy. The model is developed based on (a) interviews with a wind farm operator, engineering consultants, and operation and maintenance engineers, as well as (b) scientific literature. Our methodology involves deriving the probabilistic models of the cost model parameters based on intervals representing a subjective expert opinion on the foreseeable ranges of the parameter values. The probabilistic cost model is applied to evaluate the total I&M costs, and a sensitivity analysis is conducted to identify the main cost drivers. The model can be utilized to optimize I&M strategies at the component, structural system, and wind farm level. To illustrate its potential use, we apply it in a numerical study in which we optimize I&M strategies at the structural system level and identify and demonstrate a simplified approach of capturing uncertain I&M costs in the optimization. The simplified approach is generalized and made available for maintenance cost optimization of offshore wind turbine structures. KW - Inspection KW - Maintenance KW - Turbine support structures KW - Offshore wind KW - Costs PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626144 DO - https://doi.org/10.5194/wes-10-461-2025 SN - 2366-7443 SN - 2366-7451 VL - 10 IS - 2 SP - 461 EP - 481 PB - Copernicus Publications CY - Göttingen AN - OPUS4-62614 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Pandal, Adrián A1 - Rodríguez, Manuel Velasco A1 - Schmidt, Martin A1 - Danzi, Enrico A1 - Dufaud, Olivier A1 - Janovsky, Bretislav T1 - Investigations on different distribution systems for dusts inside the 20L-sphere N2 - The determination of several safety characteristics for dusts requires the dispersion of it in air. This is normally conducted using two vessels, one with an overpressure holding the dust and dispersing it into the second one, where the explosion takes place, through a nozzle. This procedure has the disadvantage that some dusts cannot be conveyed through the nozzle properly. Another disadvantage is that the pressure balancing between the two vessels depends on the dust loading and especially for heavy dusts and high loadings the initial pressure inside the explosion vessel might be reduced. Flocky dusts or dusts that might be dangerous to convey through a thin nozzle with an overpressure (nano powders, zirconium) are also difficult to test according to the existing standards and may not be tested with the standard nozzles, that are so far used for the determination of safety characteristics. One very recent example, testing nitrocellulose, raised the question, whether some dusts even pose a risk being distributed and pressed through a nozzle for the testing device and, in worst case, for the operator. Previous researchers have developed alternative types of nozzles for specific types of dust, but provide limited evaluation of their performance relative to standard nozzles. Additionally, researchers have not provided sufficient geometry so that they can be reproduced by others. One alternative nozzle for the dispersion of flocky or coarse dusts is stated in the ISO standard but not described there either. This article investigates four types of nozzles: The two standard ones that are widely used already, an alternative type, that got introduced into the international standard in 2016 but is still seldomly used and one that was constructed to overcome some of the observed disadvantages. The injection curves are compared with and without dust loadings as well as the explosion characteristics. Eventually, a suggestion is given for different types of dusts. KW - Dust explosions KW - Safety characteristics PY - 2024 DO - https://doi.org/10.1016/j.jlp.2024.105492 SN - 0950-4230 VL - 92 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-61697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Stoian, R. A1 - Bonse, Jörn T1 - Ultrafast Laser Nanostructuring — The Pursuit of Extreme Scales N2 - Long seen as “a solution seeking a problem,” laser pulses are nowadays – more than 60 years after their first practical demonstration – paramount in shaping and structuring matter. Harnessing their capabilities to direct intense beams of light, the number of scientific and technological developments and daily-life applications is continuously increasing. Today, the presence of lasers is ubiquitous in all sites of scientific and technological interest, from the most advanced research laboratories to industrial factories and medical hospitals. The directionality of the laser beam determines equally a local character on lightmatter interaction and as such a local modification to a material target. Furthermore, the coherence of laser radiation enables near-field or far-field scattering and interference effects that widen significantly the capabilities of controlling and tracking laser-matter interactions in space and time. Already with the advent of lasers, powerful beams of light have been directed at solid materials for a variety of purposes, making this application as old as the laser itself. The roots of the major applications for laser structuring were developed already in the 1960s, setting the base of both theoretical and experimental studies on laser ablation, with the number of publications expanding explosively during the next decades. Within this dynamic context, laser processing of materials experienced an impressive development over the years. Laser processing means specifically the capability to structure and tailor a material on its surface or even within its volume, rendering new functions and properties that are impacting the mechanical, electrical, or optical characteristics of the material. These properties are scaledependent, generating thus over the years an equally impressive quest for spatial or temporal resolution. Therefore, the developments in laser engineering with major breakthroughs, notably in pulse duration and power, always closely accompanied the efforts in material structuring with two milestones in sight: (1) yield and (2) resolution. Every step in shrinking the laser pulse duration led to a subsequent strong-impact development in process precision – particularly when the ultrashort pulse durations surpassed the fundamental electron-phonon relaxation times. Thus, minimizing heat diffusion, the advent of pulses with duration smaller than molecular or lattice vibration times has managed to confine the spatial resolution to the optical diffraction limit and sometimes even beyond. The nanoscale was already in sight at the turn of the millennium. An important question may be raised now; is there any fundamental limit in the processing resolution, a barrier defined by the intrinsic properties of light and matter? The answer has an inherently multidisciplinary nature, following the conversion of free-propagating electromagnetic radiation into material-confined energy potentially usable to drive or transform matter, and will be the focus of the present book. Relying on the experience and expertise of the leading researchers in the field, the present book intends to explore the current efforts in achieving laser processing resolution beyond the diffraction limit, laying down a perspective towards extreme laser nanostructuring. Following the most recent advances and developments, it puts forward a concept of extreme processing scales enabled by optical pulses that are able to bypass diffraction limits and achieve structuring characteristic scales beyond 100 nm. This objective can be achieved by a comprehensive understanding on how light can change matter and how, in turn, matter can change light, allowing jointly for actively controlling light and material processes. In order to give an extended perspective on the current state-of-the-art in the field of precision laser structuring, the book is divided into three main parts. The first part of the book (Part I: Fundamental Processes) offers a perspective into the fundamentals of laser-matter interaction on extreme spatial scales, with a description of the most advanced modeling efforts in understanding energy deposition in matter, a plethora of material-relaxation pathways, as well as advanced concepts for probing and observing matter in motion. Roadmaps for energy localization will be developed, and the atomistic perspective of laser ablation visualized. Theoretical modelling enables in-depth insights on ultrafast quantum processes at the nanoscale. Laser-driven self-organization at surfaces will be dissected regarding the question of how light drives material periodic patterns down to the nanoscale, explored and transmitted to its ultimate limits of an atomic printer, and immediately complemented by the unprecedented capabilities of ultrafast in-situ observation approaches for tracking the laser-induced material response with extreme spatial and temporal resolution. In the second part of the book (Part II: Concepts of Extreme Nanostructuring), distinct concepts will be developed and explored that allow confinement of light and harnessing of a material response restricted to nano- or mesoscopic scales at surfaces or in the volume of irradiated materials. A special focus will be on optical near-field related approaches for localizing light on scales even below the optical diffraction limit and plasmonic printing. Spatial and temporal beam-shaping and tailored interference techniques are discussed in the context of ultrashort laser pulses, and insights into some extreme states of matter realized by the tight confinement of laser energy are presented. The ultimate limits of writing waveguides in the bulk of dielectrics and for manifesting 3D-nanolithography are elucidated. Plasma-based surface treatments can significantly enhance the vertical precision of surface processing through etching processes. Finally, the third part of the book (Part III: Applications) leads us to a number of resuming applications, unveiling the tremendous capabilities of surface functionalization through laser micro- and nanostructuring, assessing the 3D-writing of waveguides in the bulk of dielectrics or semiconductors for enabling new branches of integrated photonics, and summarizing related applications ranging from nanophotonics to nanofluidics and from optical sensing to biomedical applications, including the latest capabilities of refractive eye surgery. This part will analyze the applications’ compatibility in yield and reproducibility with current industrial requirements, costs, and intellectual property aspects. It expands the involved spatial scales by more than eight orders of magnitude, when extending extremely small structures featuring sizes of few tens of nanometers to larger dimensions in the meter range. Thus, from surfaces to the bulk, from subtractive to additive manufacturing approaches, from advanced theoretical frames to practical technological processes – we invite the readers here to an exciting journey into the varicolored landscape of extreme laser nanostructuring. The idea of this book project was seeded in early 2020. We were delighted about the numerous and extremely positive responses from the laser-processing community, quickly receiving commitments for more than 30 individual book chapters. About 2500 communications later, the book is published. We would like to thank all authors of this book project for their insightful and detailed chapters, reviewing and reporting on this fascinating topic of the pursuit of extreme scales in ultrafast laser nanostructuring. Moreover, we would like to acknowledge the professional help and guidance of the staff of Springer Nature. Finally, we hope you will enjoy reading this book as much as we have enjoyed putting it together. Saint Etienne, France Razvan Stoian Berlin, Germany Jörn Bonse December 2022 KW - Laser nanostructuring KW - Surface engineering KW - Nonlinear lithography KW - Self-organization KW - Laser-induced periodic surface structures, LIPSS PY - 2023 SN - 978-3-031-14752-4 SN - 978-3-031-14751-7 DO - https://doi.org/10.1007/978-3-031-14752-4 SN - 0342-4111 VL - 239 SP - 1 EP - 1245 PB - Springer Nature Switzerland AG CY - Cham ET - 1 AN - OPUS4-57294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha T1 - Numerical modelling of compression stress relaxation and compression set of elastomer O-rings during aging N2 - Elastomer seals are used in many industrial applications due to their excellent mechanical properties at a wide range of temperatures. Their high versatility and recovery potential under several load conditions make them well suitable for the application in containers designed for transport, storage and/or disposal of radioactive materials. In containers for low and intermediate level radioactive waste, elastomer seals are used as barrier seals, and as auxiliary seals in storage and transportation casks (dual purpose casks) for heat generating radioactive waste, such as spent fuel and high-level waste. While a seal exchange at defined intervals is typical in many conventional applications, it is impossible or at least hard to perform when principles of minimization of radiation exposure have to be considered and prohibit an unnecessary cask handling. An extensive knowledge of the change of the elastomer’s properties during aging and the availability of reliable end-of-lifetime criteria to guarantee the permanent safe enclosure of the radioactive material is mandatory. As BAM is involved in most of the national cask licensing procedures and in the evaluation of cask-related long-term safety issues, great efforts have been already made and are still planned to scientifically support this task. Compression stress relaxation and compression set were identified as key indicators of elastomer long-term performance and quantitatively investigated in comprehensive test programs. Among other representative types of elastomers, specimens made from ethylene propylene diene rubber (EPDM) were tested before, during and after aging to capture the most important of their complex mechanical properties. In the presented study, exemplary results were used to simulate the compression stress relaxation and the compression set of elastomer O-rings during aging. Regarding the influence of temperature, the time temperature superposition principle is applied in the relaxation analysis of elastomer O-rings. The proposed model is implemented in the commercial finite element software ABAQUS/Standard® [1] with a sequential temperature displacement coupling. Numerical results match the experimental compression stress relaxation measurements well. The prediction of compression set values after long-term aging shows a relatively good agreement with the experimental results. Nevertheless, all input parameters derived from the specimen tests, additional assumptions concerning boundary conditions and modeling strategy are discussed with regard to the identified slight discrepancies. The possibility to extend the finite element model to represent the O-ring seal’s ability to recover after a (fast) partial release is taken into account T2 - ASME 2020 Pressure Vessels & Piping Conference (PVP2020) CY - Online meeting DA - 03.08.2020 KW - Stress relaxation KW - Ageing KW - Compression Set KW - O-ring KW - Sequential analysis KW - Simulation PY - 2020 AN - OPUS4-52135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Elastomer seals - overview and development N2 - The talk summarizes the current and future investigations of elastomer seal materials in division 3.4. T2 - IRSN-BAM Symposium Safety of Transport and Storage Packages CY - Online meeting DA - 19.11.2020 KW - Seal KW - Degradation KW - Ageing PY - 2020 AN - OPUS4-51751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sagradov, Ilja T1 - Long-term tests and numerical simulations on metal seals based on continuous force measurement in compressed state N2 - In Germany, the search for a disposal site for heat-generating radioactive waste will take decades longer than originally assumed. Transport and storage casks must therefore ensure safe containment for extended interim storage periods, possibly over 100 years. In order to maintain the required leak tightness, spring core metal seals with aluminum or silver cladding are used. As sealing force decreases over time, BAM has been conducting tests for over 15 years to prove their long-term reliability. This work - a joint project of BASE and BAM - aims to obtain additional material data using a new device for continuous measurement of compression force over time and temperature for lifetime prediction models and is supported by FEM simulations. Initial tests on aluminum and silver seals have been completed, and first results are presented. T2 - safeND 2025 CY - Berlin, Germany DA - 17.09.2025 KW - Interim storage KW - Metal seal KW - Restoring force PY - 2025 AN - OPUS4-64991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias T1 - Creep Investigations on Aluminum Seals for Application in Radioactive Waste Containers N2 - In Germany spent nuclear fuel (SNF) and high level radioactive waste (HLW) are stored in interim storage containers with double lid systems. Those lids are equipped with metal seals (e.g. Helicoflex®) that ensure the safe enclosure of the inventory. Being licensed for up to 40 years of interim storage the evaluation of the long-term behavior of the seals is necessary, taking into account storage conditions, decay heat and possible mechanical loads. T2 - International Conference on Aluminum Alloys CY - Montreal, Canada DA - 17.06.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 AN - OPUS4-45843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Simulation of compression set of epdm o-rings during aging N2 - It is common practice in the application of finite element analysis to model compression set (CS) of elastomers during aging with two different material models according to the two-network theory of Tobolsky. The theory relies on the existence of two networks. The first one represents the original network after vulcanization and is sensitive to chain scission. The second network accounts for the formation of additional crosslinking during aging. Besides the use of user subroutines to describe the two-network model, an element overlay technique is also needed as the full set of both material behaviors did not exist for assignment to a single element. This element overlay technique is valuable for research and developmental purposes but makes extension to industrial usage quite challenging. Our goal is to simulate the CS of elastomers after long-term aging in a commercial finite element software with no need for extra subroutine codes or mesh superposition. Ethylene propylene diene (EPDM) O-rings were aged in a compressed state at 75 °C, 100 °C, 125 °C and 150 °C for up to 183 days. Investigations of the experimental test results were used to identify material models and their parameters to develop a finite element model to simulate CS. The model was implemented in the finite element software ABAQUS/Standard® with a sequential temperature-displacement coupling. Regarding the influence of temperature, the Arrhenius equation is adopted for the time-temperature relationship. The activation energy value that is required for the simulation is firstly determined from shifting the experimental CS results with the time-temperature superposition technique and plotting the shift factors in an Arrhenius diagram. The experiments were compared with the simulation results. Afterwards different activation energies were used in the simulation and discussed. A suitable choice of the activation energy value with regard to the reference temperature and the test temperature is presented. With the chosen activation energies, the match between numerical CS values after long-term aging and the experimental results was improved. T2 - ASME 2022 Pressure Vessels & Piping Conference CY - Las Vegas, USA DA - 17.07.2022 KW - Simulation KW - Compression set KW - EPDM KW - Aging PY - 2022 SP - 1 EP - 9 AN - OPUS4-57370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Chemical and structural changes at the surface of titanium materials upon irradiation with near-infrared ultrashort laser pulses N2 - Due to its large strength-to-weight ratio and excellent biocompatibility, titanium materials are of paramount importance for medical applications, e.g. as implant material for protheses. In this work, the evolution of various types of laser-induced micro- and nanostructures emerging on titanium or titanium alloys upon irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment is studied for various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz). The morphologies of the processed surfaces were systematically characterized by optical and scanning electron microscopy (OM, SEM). Complementary white-light interference microscopy (WLIM) revealed the corresponding surface topographies. Chemical and structural changes were analysed through depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray diffraction (XRD) analyses. The results point towards a remarkable influence of the laser processing parameters on the surface topography, while simultaneously altering the near-surface chemistry via laser-induced oxidation effects. Consequences for medical applications are outlined. T2 - E-MRS Spring Meeting 2022 CY - Online meeting DA - 30.05.2022 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - ToF-SIMS KW - Chemical analysis KW - Titanium PY - 2022 AN - OPUS4-54931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Dichtungsverhalten bei niedrigen Temperaturen - Untersuchung der unteren Temperatureinsatzgrenze von Elastomerdichtungen - N2 - Elastomere werden vielfach in Produkten eingesetzt, die bei verschiedenen Temperaturen verwendet werden. O-Ringe sind kostengünstige Dichtelemente, die allerdings für die Funktionsfähigkeit und Sicherheit eines Produkts entscheidend sein können. Die untere Temperatur-einsatzgrenze ist dabei relevant und aus wissenschaftlicher Sicht nicht allgemein gültig zu definieren, da diese einerseits durch die Änderungen der Materialeigenschaften im Zuge des Gummi-Glas-Übergangs definiert werden, die Temperaturlage dieses Übergangs jedoch sehr stark von den jeweiligen Einsatzbedingungen (z.B. Frequenz) abhängt. Dadurch ergeben sich große Unterschiede zwischen statischen und dynamischen Anwendungen. Verschieden Untersuchungen sollen vorgestellt und interpretiert werden, um das Auditorium auf verschiedene Herausforderungen aufmerksam zu machen und Lösungsansätze vorzustellen. T2 - ISGATEC Forum Werkstoffe 2019 CY - Mannheim, Germany DA - 03.12.2019 KW - Dichtung KW - O-Ring KW - Tiefe Temperaturen KW - Versagenstemperatur PY - 2019 AN - OPUS4-49983 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sagradov, Ilja T1 - Long-term tests on metal seals using continuous force measurement in compressed state N2 - In Germany, spent fuel and heat generating radioactive waste is stored in casks for transport and storage (DPCs). The storage licenses were granted for up to 40 years. Due to the delay in identifying a final repository site for such radioactive waste, the storage periods are to be extended significantly. The objective of our research work is to collect additional material data for metal seals in order to be able to better assess the long-term safety of the sealing system of the casks for a period of up to 100 years. A principal safety consideration for the DPCs is the long-term performance of bolted lid sealing systems utilizing metal seals to ensure the safe enclosure of the radioactive inventory during interim storage. To assess the sealing behavior, it is necessary to examine the aging-dependent residual restoring force for the metal seals and the usable resilience. By investigating the change in these values as a function of time and temperature, further insight can be gained into the assessment of long-term safety for extended interim storage. In the present study, the restoring force of metal seals with an outer aluminum jacket and a torus diameter of 9.9 mm was measured continuously. For this purpose, a specially designed device equipped with a load cell was used under isothermal conditions. As part of the investigation, the level and rate of decrease of the restoring seal force were recorded over test periods of one and two months. The seal temperature was set to 35 °C, 75 °C, 100 °C, 125 °C, and 150 °C, respectively. A direct correlation was observed between the temperature of the seal, the level of the restoring force after compressing and heating the seal, and the drop-off characteristics of the restoring force. It was found that in our test device the force level immediately after reaching the respective temperature is lower for higher seal temperatures, while the drop rate of the restoring force is higher. This paper describes the experimental setting and discusses first results in comparison with our long-term discontinuous measurements. T2 - 21st International Symposium on the Packaging and Transportation of Radioactive Materials - PATRAM 2025 CY - San Antonio, TX, USA DA - 27.07.2025 KW - Temperature-Dependent Performance KW - Extended Interim Storage KW - Long-Term Safety Assessment KW - Metal Seal Aging KW - Restoring Force Degradation PY - 2025 AN - OPUS4-63891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -