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    <title>https://opus4.kobv.de/opus4-bam</title>
    <description>OPUS documents</description>
    <link>https://opus4.kobv.de/opus4-bam/index/index/</link>
    <pubDate>Mon, 20 Apr 2026 11:17:39 +0200</pubDate>
    <lastBuildDate>Mon, 20 Apr 2026 11:17:39 +0200</lastBuildDate>
    <item>
      <title>Beware the artifact: Generation of ellagic acid and related species during atmospheric solid analysis probe (ASAP) measurements of iron gall inks and tannins in the negative ionization mode</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65925</link>
      <description>A detailed comparative analysis of the results of atmospheric solid analysis probe (ASAP) mass spectrometry of inks, tannins, and gallic acid (GA) in the negative ionization mode was performed. Results obtained for tannin by ASAP have been compared with those obtained with electrospray ionization (ESI). Apart from the GA ion, measurements frequently also yielded anions corresponding to association products and condensation products. At zero collision energy, pure GA gave a dimeric adduct (m/z 339); the formation of ions at m/z 303 and 304 was favored by increased temperatures and collision energies. In the case of inks, the subsequent dehydrogenation of such species to ellagic acid (EA) (m/z 301) was attributed to the oxidative effect of the iron III ion. On the basis of the results, a modification of the “standard ink protocol” has been suggested. Furthermore, several yet non‐described breakdown products and radical ion species of GA and EA ions were identified.</description>
      <author>Thomas Willms</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65925</guid>
      <pubDate>Mon, 20 Apr 2026 11:17:39 +0200</pubDate>
    </item>
    <item>
      <title>Towards a deeper understanding of the oxidation of isobutane to tert-butyl hydroperoxide in the liquid phase by an extended kinetic model - Initiation by di-tert-butyl peroxide</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65921</link>
      <description>To date, the liquid phase oxidation of isobutane has not been comprehensively described in the literature, since&#13;
the established kinetic models include either the effect of the initiator or the autocatalytic nature of the oxidation&#13;
of isobutane, but not both. To overcome this deficiency, an extended kinetic model was developed and validated&#13;
using experimental data from the literature. It enabled for the first time the distinction of three different processes:&#13;
the oxidation of isobutane, the heterogeneous, unimolecular decomposition of tert-butyl hydroperoxide&#13;
on the reactor wall and the homogeneous decomposition reactions of TBHP in solution. The rate constant of the&#13;
heterogeneous unimolecular decomposition of TBHP on the wall surface of an untreated stainless-steel reactor,&#13;
was found to be two to five times higher than that which was observed in a passivated steel reactor. However,&#13;
similar values for the respective parameters describing the first-order decomposition of TBHP and the oxidation&#13;
of isobutane were obtained in both reactors. In the non-passivated stainless-steel reactor, the second order&#13;
decomposition of TBHP was absent. The results were compared with published data.</description>
      <author>Thomas Willms; Holger Kryk; Uwe Hampel</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65921</guid>
      <pubDate>Mon, 20 Apr 2026 10:51:37 +0200</pubDate>
    </item>
    <item>
      <title>Advancing IR Laser Thermography in Composites via Thermal Analysis-Informed Machine Learning</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65914</link>
      <description>Machine learning-assisted passive thermography has emerged as a powerful tool for characterizing fatigue damage through self-heating-induced temperature hotspots, with its accuracy depending critically on the precise determination of the governing thermal properties. This work proposes a nondestructive method to simultaneously recover the transverse conductivity k_ct and the film coefficient h ─ two thermal parameters that are typically difficult to measure. To this end, a near-infrared laser in conjunction with a DLP-based spatial light modulator was used to create artificial temperature hotspot distributions by illuminating one side of a ±45° glass-epoxy composite laminate. The generated surface temperature distribution on the opposite side ─ denoted as ground truth (GT) ─ was recorded by a cooled midwave infrared thermal camera. Bayesian optimization (BO) was subsequently employed to iteratively suggest the best k_ct and h values for use in a 3D FEM thermal model, which in turn generated synthetic thermal images as similar as possible to the GT. Different BO runs converged after about 10 iterations, yielding effective values of k_ct = 0.40 (W/m K) and h = 5.78 W/(m^2 K), from where the loss objective decreased by a factor of ca. 3 within only seven iterative rounds. A final experimental validation using these optimized parameters successfully reproduced three independent thermal images with only minor deviations, demonstrating the robustness and applicability of the proposed approach.</description>
      <author>R. Albuquerque; Julien Lecompagnon; A. Sarhadi; H. Ruckdäschel; M. Eder</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65914</guid>
      <pubDate>Fri, 17 Apr 2026 11:32:56 +0200</pubDate>
    </item>
    <item>
      <title>Parameter-efficient fine-tuning of machine-learning interatomic potentials for phonon and thermal properties</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65893</link>
      <description>Machine-learning interatomic potentials are widely used as computationally efficient surrogates for density functional theory in atomistic simulations, enabling large-scale, long-time modeling of materials systems. We investigate how different fine-tuning strategies influence the prediction of harmonic phonon band structures, thermal properties, and the potential energy surface along imaginary phonon modes. We achieve substantial accuracy improvements with minimal additional data, with as few as 10 additional training structures already yielding significant gains. In addition to existing approaches, we introduce Equitrain, a finetuning framework that implements LoRA-based adaptation. Across 53 materials systems, we show that fine-tuned models consistently outperform both the underlying pretrained model and models trained from scratch. Equitrain achieves the best overall performance, and our results demonstrate that fine-tuning enables accurate phonon predictions.</description>
      <author>Jonas Grandel; Philipp Benner; Janine George</author>
      <category>preprint</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65893</guid>
      <pubDate>Fri, 17 Apr 2026 10:56:12 +0200</pubDate>
    </item>
    <item>
      <title>Perspective: Towards sustainable exploration of chemical spaces with machine learning</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65891</link>
      <description>Artificial intelligence is transforming molecular and materials science, but its growing computational and data demands raise critical sustainability challenges. In this Perspective, we examine resource considerations across the AI-driven discovery pipeline--from quantum-mechanical (QM) data generation and model training to automated, self-driving research workflows--building on discussions from the ``SusML workshop: Towards sustainable exploration of chemical spaces with machine learning'' held in Dresden, Germany. In this context, the availability of large quantum datasets has enabled rigorous benchmarking and rapid methodological progress, while also incurring substantial energy and infrastructure costs. We highlight emerging strategies to enhance efficiency, including general-purpose machine learning (ML) models, multi-fidelity approaches, model distillation, and active learning. Moreover, incorporating physics-based constraints within hierarchical workflows, where fast ML surrogates are applied broadly and high-accuracy QM methods are used selectively, can further optimize resource use without compromising reliability. Equally important is bridging the gap between idealized computational predictions and real-world conditions by accounting for synthesizability and multi-objective design criteria, which is essential for practical impact. Finally, we argue that sustainable progress will rely on open data and models, reusable workflows, and domain-specific AI systems that maximize scientific value per unit of computation, enabling efficient and responsible discovery of technological materials and therapeutics.</description>
      <author>Leonardo Medrano Sandonas; David Balcells; Anton Bochkarev; Jacqueline M. Cole; Volker L. Deringer; Werner Dobrautz; Adrian Ehrenhofer; Thorben Frank; Pascal Friederich; Rico Friedrich; Janine George; Luca Ghiringhelli; Alejandra Hinostroza Caldas; Veronika Juraskova; Hannes Kneiding; Yury Lysogorskiy; Johannes T. Margraf; Hanna Türk; Anatole von Lilienfeld; Milica Todorović; Alexandre Tkatchenko; Mariana Rossi; Gianaurelio Cuniberti</author>
      <category>preprint</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65891</guid>
      <pubDate>Fri, 17 Apr 2026 10:28:19 +0200</pubDate>
    </item>
    <item>
      <title>Tensile Test Ontology (TTO)</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65909</link>
      <description>This is the tensile test ontology (TTO) in version 3.0.0 as developed on the basis of the tensile test standard ISO 6892-1:2019-11: Metallic materials - Tensile Testing - Part 1: Method of test at room temperature.&#13;
&#13;
The TTO was developed in the frame of the project Plattform MaterialDigital (PMD). The TTO provides conceptualizations valid for the description of tensile tests and corresponding data in accordance with the respective test standard. By using TTO for storing tensile test data, all data will be well structured and based on a common vocabulary agreed upon by an expert group (generation of FAIR data) which will lead to enhanced data interoperability. Due to the import of the PMD core ontology (PMDco), here in version 3.0.0, the interoperability of tensile test data is enhanced and querying in combination with other aspects and data within the broad field of material science and engineering (MSE) is facilitated.</description>
      <author>Markus Schilling; Bernd Bayerlein; J. Waitelonis; H. Birkholz; P. von Hartrott</author>
      <category>researchdata</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65909</guid>
      <pubDate>Fri, 17 Apr 2026 09:41:57 +0200</pubDate>
    </item>
    <item>
      <title>Poly(trimethylene terephthalate) − solid state polycondensation and the formation of monodisperse Extended-Ring crystals</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65907</link>
      <description>Linear, low-molar-mass poly(trimethylene terephthalate) (PTT) was synthesized via the polycondensation of 1,3-propanediol and dimethyl terephthalate and investigated by matrix-assisted laser desorption/ionization time of flight (MALDI TOF) mass spectrometry, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and x-ray scattering. The obtained PTT was used in crystalline plaque or powder form for studies of its solid-state polycondensation (SSP). The combination of powder and vacuum increased the number-average molecular weight (Mn) by a factor of three. Interestingly, even-numbered cycles with degrees of polymerization (DPs) between six and 16 were preferentially formed. Annealing after doping with tin catalysts produced three cyclic main reaction products (C10, C12 and C14), which suggest that thermodynamic control of transesterification processes favors the formation of three types of monodisperse extended-ring crystallites (ERC) with thicknesses of 5, 6 of 7 repeat units. Additionally, a predominantly cyclic PTT was prepared, once again demonstrating the formation of even-numbered ERC upon annealing. Crystallinities calculated from WAXS measurements showed satisfactory agreement with those determined by DSC. SAXS measurements confirmed that the crystal thickness defined by ERC is also valid for long chains and large cycles that crystallize with chain folding.</description>
      <author>Hans R. Kricheldorf; Steffen Weidner; Andreas Meyer; Paul Buijsen</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65907</guid>
      <pubDate>Fri, 17 Apr 2026 09:26:09 +0200</pubDate>
    </item>
    <item>
      <title>Zerstörungsfreie Detektion verdeckter Risse in Eisenbahn-Spannbetonschwellen – Wo stehen wir aktuell?</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65910</link>
      <description>Verdeckte Risse in Eisenbahn-Spannbetonschwellen können zum plötzlichen Versagen der Schwelle und dem Verlust der Spurhaltefähigkeit führen. Im schlimmsten Fall kann dies bei Überfahrt eines Schienenfahrzeugs eine Entgleisung bewirken. Einige Risstypen entstehen im Inneren der Schwelle und breiten sich unerkannt aus. Dies führt weit vor der äußeren Sichtbarkeit bereits zu einer deutlichen Minderung der Querschnittsfestigkeit und damit Instabilität der Schwelle.</description>
      <author>S. Hillmann; Christoph Strangfeld</author>
      <category>poster</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65910</guid>
      <pubDate>Fri, 17 Apr 2026 09:16:38 +0200</pubDate>
    </item>
    <item>
      <title>The influence of relative humidity on drying shrinkage mechanisms in hybrid alkaline systems with bottom ash and rice husk ash</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65906</link>
      <description>This study investigated the influence of relative humidity (RH = 30%, 60 %, and 90 %) on the drying shrinkage behaviour of hybrid alkaline cement (HAC) systems, composed of 30 % Portland cement and 70 % bottom ash (BA) and/or rice husk ash (RHA). At RH &lt; 30 %, HAC mortars exhibited shrinkage strains up to 7 times higher than Portland cement, whereas curing at RH &gt; 90 % reduced shrinkage by nearly 15-fold compared to dry conditions. The 70RHA mixture demonstrated the highest shrinkage under low RH, associated with its refined micropore structure and elevated internal surface area. Nitrogen adsorption-desorption analysis revealed that low RH hindered pore refinement, while wet curing promoted gel densification, increasing the fraction of pores below 5 nm and improving compressive strength. At intermediate RH, mesopore volume increased after 28 days, consistent with microstructural changes associated with moisture exchange processes. This work provides a combined analysis of humidity-dependent shrinkage mechanisms and pore structure evolution in hybrid alkaline systems incorporating industrial and agricultural residues. The main contribution lies in identifying two distinct shrinkage regimes governed by pore-scale mechanisms under different RH conditions, offering practical guidance for curing optimisation and dimensional stability control in sustainable cementitious materials.</description>
      <author>M. C. de Moraes; Luís Urbano Durlo Tambara; M. Cheriaf; J. C. Rocha</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65906</guid>
      <pubDate>Fri, 17 Apr 2026 09:15:02 +0200</pubDate>
    </item>
    <item>
      <title>Gaussian mixture models for model improvement</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65905</link>
      <description>Modeling complex physical systems such as they arise in civil engineering applications requires finding a trade-off between physical fidelity and practicality. Consequently, deviations of simulation from measurements are ubiquitous even after model calibration due to the model discrepancy, which may result from deliberate modeling decisions, ignorance, or lack of knowledge. If the mismatch between simulation and measurements are deemed unacceptable, the model has to be improved. Targeted model improvement is challenging due to a non-local impact of model discrepancies on measurements and the dependence on sensor configurations. Many approaches to model improvement, such as Bayesian calibration with additive mismatch terms, gray-box models, symbolic regression, or stochastic model updating, often lack interpretability, generalizability, physical consistency, or practical applicability. This paper introduces a non-intrusive approach to model discrepancy analysis using mixture models. Instead of directly modifying the model structure, the method maps sensor readings to clusters of physically meaningful parameters, automatically assigning sensor readings to parameter vector clusters. This mapping can reveal systematic discrepancies and model biases, guiding targeted, physics-based refinements by the modeler. The approach is formulated within a Bayesian framework, enabling the identification of parameter clusters and their assignments via the Expectation-Maximization (EM) algorithm. The methodology is demonstrated through numerical experiments, including an illustrative example and a real-world case study of heat transfer in a concrete bridge.</description>
      <author>P. Villani; Daniel Andés-Arcones; Jörg F. Unger; M. Weiser</author>
      <category>preprint</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65905</guid>
      <pubDate>Fri, 17 Apr 2026 09:10:53 +0200</pubDate>
    </item>
    <item>
      <title>BAM Inside #2/2026</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65908</link>
      <description/>
      <author/>
      <category>newsletter</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65908</guid>
      <pubDate>Thu, 16 Apr 2026 14:33:26 +0200</pubDate>
    </item>
    <item>
      <title>Influence of initial powder oxidation on mechanical properties of components fabricated via PBF-LB/M</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65904</link>
      <description>The reuse of feedstock in laser powder bed fusion of metals (PBF-LB/M) enhances sustainability and reduces production costs but is limited by progressive degradation of the material [1]. One contributor to powder degradation is oxidation, even in protective atmospheres [2]. This study investigates how the initial oxidation state of Haynes 282, a nickel-based alloy for high-temperature applications, influences its performance at both ambient and elevated temperatures (850 °C). For this purpose, four feedstock batches with oxygen contents ranging from approximately 140 ppm to 1400 ppm were produced by controlled oxidation of virgin powder in a laboratory furnace.&#13;
Microscopy analysis revealed that higher oxidation levels promoted irregular melt pool morphology and increased surface roughness, accompanied by a reduction in grain size. Electron probe microanalysis revealed that the oxide layers observed on the surface of the manufactured specimens in the as-build condition consisted primarily of aluminium and titanium oxides. Oxygen analysis via inert gas fusion on heat-treated specimens measured approximately 90 ppm in material from virgin feedstock and approximately 600 ppm in material from the most oxidized batch. Notwithstanding these discrepancies, the part porosity and the room-temperature tensile properties, including ultimate strength and elongation at break, remained largely unaltered. Conversely, creep testing at elevated temperatures under application-relevant conditions showed a pronounced decline in creep resistance and a corresponding increase in creep strain with rising oxygen content. However, both the tensile strength and the deformation mechanisms observed in high-temperature tensile tests remained comparable across all batches. These findings indicate that while the use of oxidized powder is viable for less demanding service conditions, strict powder quality control is imperative when manufacturing components for high-temperature applications.</description>
      <author>Josué Dávila</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65904</guid>
      <pubDate>Thu, 16 Apr 2026 07:26:32 +0200</pubDate>
    </item>
    <item>
      <title>Postcarbone road: Limits and possibilities of cyclic bitumen rejuvenation</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65903</link>
      <description>In road construction, the reuse of reclaimed asphalt depends on the addition of large quantities of fresh binder. Bio-based rejuvenators can represent a sustainable alternative to this, but their performance concerning multiple reuses has yet to be investigated. For this study, fresh 50/70 bitumen was subjected to up to four ageing and rejuvenation cycles using eight commercially available rejuvenators (five bio- and three petroleum-based). The rheological and chemical evaluation of the raw materials and resulting products was carried out using a dynamic shear rheometer and Fourier transform infrared spectrometer. Through examina-tion of the infrared spectra, the rejuvenators were divided into three groups based on similar chemical compo-sition.  Further,  evaluated  optimum  dosage  quantities  required  to  rejuvenate  aged  binder  indicate  that  bio-based rejuvenators are more resource-efficient than their petrol-based counterparts. Finally, a most promising bio-based rejuvenator candidate was found, allowing up to four reuse cycles.</description>
      <author>Simon Alexander Schröder; Sandra Weigel; N. Nytus; J. Dominik; M. Radenberg; K. Schwettmann; M. Cheng; D. Stephan</author>
      <category>conferenceobject</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65903</guid>
      <pubDate>Thu, 16 Apr 2026 07:04:24 +0200</pubDate>
    </item>
    <item>
      <title>Thermal decomposition in blended cement systems and its effect on fire-inducedconcrete spalling: Insights from XRD and TGA</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65902</link>
      <description>Blended cements are gaining increasing popularity due to their lower CO2-footprint in compar-ison to ordinary Portland cement (OPC). However, this growing use raises the potential risk of buildings made with blended cement concrete being exposed to fire,which can lead to heavy damages caused by explosive concrete spalling. It has already been shown that the cement type strongly influences the fire-induced concrete spalling and the thermally induced moisture transport, however, to understand the mechanisms behind these findingsthe thermal decompo-sition behavior of the cementitious matrix must be investigated more systematically. Therefore, the phase content of three blended cement pastes (CEM II/A-LL, CEM III/A and CEM II/B-Q) was studied in comparison with a Portland cement paste (CEM I) after temperature exposure to 20 ◦C, 105 ◦C, 300 ◦C and 500 ◦C. Clear differences in the initial phase composition and their dehy-dration behavior between the individual cement types were recognized. In conclusion, blended cements showed lower amounts of AFt and AFm phases and additionally lower amounts of portlandite and C-(A)-S-H were found in CEM III/A and CEM II/B-Q pastes. The results suggest that higher AFt and AFm contents in CEM I, which are associated with greater water release at relatively low temperatures may ultimately reduce the spalling risk. Furthermore, C-(A)-S-H in CEM III/A and CEM II/B-Q showed increased thermal stability and large amounts of non-hydrated phases were found in every blended cement paste. Both of those aspects might contribute to thermomechanical spalling and the overall increased spalling susceptibility observed in blended cement concrete.</description>
      <author>Tim Pittrich; Daniel Jansen; Frank Weise; Ludwig Stelzner; Frank Dehn</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65902</guid>
      <pubDate>Wed, 15 Apr 2026 14:04:13 +0200</pubDate>
    </item>
    <item>
      <title>Thermally induced moisture transport in concrete with diffeent types of blended Portland cement studied by 1H‑NMR relaxometry</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65901</link>
      <description>Clinker-reduced cements are gaining in popularity as part that utilization of these cements negatively influence the fie-induced spalling behavior of concrete, which is highly influenced y thermohydraulic damage mechanisms. Therefore, thermally induced moisture transport in normal strength concretes made with dif-ferent types of blended cements (CEM I, CEM II/A-LL, CEM III/A and CEM II/B-Q) was investigated by means of 1H-NMR relaxometry in combination with supportive side investigations concerning permeabil-ity and porosity. In addition, a numerical model was used to analyze in-situ moisture development during high temperature exposure. The results show that the cement type influences bth initial moisture content and pore size-specific moiture distribution. This was primarily reflected in an inceased water content in CEM III/A and CEM II/B-Q concretes as well as a comparable high gel pore water fraction in CEM II/B-Q concrete before heating. After heating, a similar degree of pore coarsening from gel to capillary pore was observed in all samples. Although the measure-ments were only conducted after, not during, high temperature exposure, the depth of the drying front and the extent of the moisture clog could be deter-mined. With the additional numerical analysis, it can be assumed that during high temperature load, the drying front is less advanced and the moisture clog even more pronounced. In conclusion, it can be stated that the increased spalling susceptibility in blended cement concrete is caused by the lower initial perme-ability and increased moisture content.</description>
      <author>Tim Pittrich; S. Peters; G. Meschke; Frank Weise; Ludwig Stelzner</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65901</guid>
      <pubDate>Wed, 15 Apr 2026 14:00:24 +0200</pubDate>
    </item>
    <item>
      <title>Embedded Model Form Uncertainty Quantification with Measurement Noise for Bayesian Model Calibration</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65899</link>
      <description>A key factor in ensuring the accuracy of computer simulations that model physical systems is the proper calibration of their parameters based on real-world observations or experimental data. Bayesian methods provide a robust framework for quantifying and propagating the uncertainties that inevitably arise. Nevertheless, they produce predictions unable to represent the observed datapoints when paired with inexact models. Additionally, the quantified uncertainties of these overconfident models cannot be propagated to other Quantities of Interest (QoIs) reliably. A promising solution involves embedding a model inadequacy term in the inference parameters, allowing the quantified model form uncertainty to influence non-observed QoIs. In this work, we revisit this embedded formulation and analyze how different likelihood constructions affect the inference of model form uncertainty, particularly under the presence of prescribed measurement noise and unavoidable model discrepancies. Two additional likelihood formulations, the global moment-matching and relative global moment-matching likelihoods, are introduced to explore alternative ways of representing the residual distribution. The behavior of these likelihoods is examined alongside existing formulations to show how different treatments of measurement noise and discrepancies shape the inferred parameter posteriors, and thereby affect the uncertainty ultimately propagated to the QoIs. Particular attention is given to how the uncertainty associated with the model inadequacy term propagates to the QoIs for the posteriors obtained from different likelihood formulations, enabling a more comprehensive statistical analysis of the prediction’s reliability. Finally, the proposed approach is applied to estimate the uncertainty in the predicted heat flux from a transient thermal simulation using temperature observations</description>
      <author>Daniel Andrés Arcones; M. Weiser; P-S. Koutsourelakis; Jörg F. Unger</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65899</guid>
      <pubDate>Wed, 15 Apr 2026 12:14:25 +0200</pubDate>
    </item>
    <item>
      <title>Back to the roots: Line-focus convoluted models in small-angle X-ray scattering</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65897</link>
      <description>We present analytically convoluted expressions for models commonly used in small-angle X-ray scatteringv(SAXS), specifically for measurements made with instruments operating in line-focus (Kratky-type) or Ultra-SAXS (Bonse-Hart) geometries. Starting with Guinier's approximation for determining the radii of gyration, we discuss power laws, random-coil conformations of macromolecules, and spherical nanoparticles. We provide expressions for the Guinier-Porod model, the Teubner-Strey model (for microemulsions), and the generalized Ornstein-Zernike model (for gels and nanogels1). An example of the Teubner-Strey model is provided. The line-convoluted models discussed here are intended for interpreting data that has not been deconvoluted (i.e., not "desmeared"). Using line-convoluted data allows for lower detection limits and shorter measurement times compared to deconvoluted data, as artifacts introduced by deconvolution can be avoided by applying these models. We suggest utilizing line-convoluted models for high-throughput in-house SAXS analysis, which could enable time-saving routine examinations. For instance, SAXS investigations could help determine whether certain materials should be classified as nanomaterials under the European Commission's regulatory.</description>
      <author>Andreas Thünemann</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65897</guid>
      <pubDate>Wed, 15 Apr 2026 12:09:32 +0200</pubDate>
    </item>
    <item>
      <title>Grundlegende Designprinzipien von Flammensperren für zerfallsfähige Gase</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65895</link>
      <description>Es werden Erkenntnisse aus experimentellen Untersuchungen mit Tetrafluorethylen (TFE) im Realmaßstab hinsichtlich der Wirksamkeit dreier unterschiedlicher Typen von Flammensperren in insgesamt 7 Experimenten berichtet und deren physikochemische Wirkmechanismen diskutiert.</description>
      <author>Christian Liebner</author>
      <category>poster</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65895</guid>
      <pubDate>Wed, 15 Apr 2026 12:07:28 +0200</pubDate>
    </item>
    <item>
      <title>Mimose-A - Multimodale IoT-Devices zur umfassenden und selbstlernenden Anlagenüberwachung</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65894</link>
      <description>Der Mensch ist in der Lage, sehr schnell den Zustand seiner Umgebung zu erfassen, indem er Informationen über verschiedene Sinneskanäle aufnimmt und miteinander verarbeitet. Für technische Systeme steht heute eine Vielzahl preiswerter Sensoren zur Verfügung, die in ihrer Leistungsfähigkeit teils deutlich über die menschlichen Sinnesorgane hinausgehen. Dennoch ist eine ähnlich umfassende Bewertung der Umgebung noch nicht möglich, weil die einzelnen Sensordaten nicht ausreichend fusioniert und interpretiert werden.&#13;
In der Anlagenüberwachung nicht nur in der chemischen Industrie sind heute dedizierte, d. h. für genau eine spezifische Applikation ausgelegte Sensorsysteme üblich, meist verbunden mit hohen Kosten, u. a. wegen der geringen Stückzahlen, die keine Economy of Scale erlauben. Ergänzt werden diese begrenzten technischen Systeme durch den Menschen, der mit seiner 'Sensorik' ungewöhnliche Zustände und mögliche Gefahrensituationen allerdings nur punktuell erfassen kann.&#13;
&#13;
Durch die Verfügbarkeit ausreichender Rechenleistung zur Interpretation der entstehenden Datenflut ist ein Paradigmenwechsel in der sensorischen Überwachung von Anlagen möglich, der in diesem Projekt erstmalig adressiert werden soll. Erwünscht ist eine flächige Erfassung multimodaler Anlagendaten und damit eine deutliche Verbesserung der Bewertungsmöglichkeiten, z.B. zur frühzeitigen Erkennung von Leckagen bei Energie-trägern (Druckluft, Wasserdampf, Gas und zukünftig zunehmend Wasserstoff).</description>
      <author>Patrick P. Neumann; A. Schütze</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65894</guid>
      <pubDate>Wed, 15 Apr 2026 12:04:29 +0200</pubDate>
    </item>
    <item>
      <title>Second Life Verwendungen - Untersuchungen und erste Erfahrungen mit einem Ausbildungsdemonstrator</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65888</link>
      <description>Der Vortrag gibt zunächst einen Themeneinstieg in den Bereich der Second-Life-Batterien sowie rechtliche und technische Grundlagen zu Lebenszyklus und Alterung. Im Weiteren werden experimentelle Ergebnisse aus Versuchen zum thermischen Durchgehen mit Batteriemodulen aus dem BMBF-Vorhaben SEE-2L vorgestellt. Darüber hinaus wird ein eigens entwickelter Ausbildungsdemonstrators vorgestellt, welcher einen wesentlichen Baustein des Ergebnistransfers aus dem Vorhaben darstellt.</description>
      <author>Sarah-K. Hahn</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65888</guid>
      <pubDate>Wed, 15 Apr 2026 11:33:41 +0200</pubDate>
    </item>
    <item>
      <title>Polypyrrole membranes in fuel cells: insights into material properties and performance</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65885</link>
      <description>Purpose&#13;
The purpose of this paper is to outline replacements for conventional Nafion membranes for fuel cells that are plagued by high cost, biofouling and pH induced degradation. It targets the conducting polymer polypyrrole (Ppy) function in developing non-fluorinated polymer electrolyte membranes (PEM) as an adequate and superior replacement.&#13;
Design/methodology/approach&#13;
This is an integrative review. It critically evaluates and integrates existing scientific evidence on the use of polypyrrole (Ppy) in composite membranes for PEM fuel cells. The study is grounded on the method of how Ppy is used to modify and improve non-fluorinated base membranes’ characteristics.&#13;
Findings&#13;
The review finds composite membranes with polypyrrole (Ppy) to be very promising. It finds that Ppy enables proton transport channels to be formed at high temperature, enhances thermal and mechanical stability, provides corrosion protection to the bipolar plates and inhibits crossover of methanol. There are also serious limitations found, such as intrinsic low proton conductivity of Ppy, instability and complicated processing.&#13;
Originality/value&#13;
Originality in this review is the strict critical scrutiny of maximizing polypyrrole as a fuel cell material. It is greater than mere listing of benefits in that it transparently warrants future research requirements. This review stands out for the fact that it has a comprehensive list of ideas on how to improve, e.g. improving proton conductivity without compromising other characteristics, improving resistance to overoxidation and degradation, improving mechanical/thermal properties, making synthesis easy for scaling up and achieving regular morphology with controlled water uptake for engineering efficient membrane composites. The paper’s strength lies in its breadth and integrative approach – the review is not only surveys what has been done but also openly identifies challenges and future research opportunities.</description>
      <author>Saeed Ahmed; Ahmed Medhat; Omar Abou-Deif; Mohamed Housein; Mahmoud Afifi; Mohamed El-Shamy; Alaa Fahmy</author>
      <category>article</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65885</guid>
      <pubDate>Wed, 15 Apr 2026 11:31:11 +0200</pubDate>
    </item>
    <item>
      <title>SmartWeld - Innovatives Design- und Fertigungskonzept zur Steigerung der Leichtbaupotenziale im Stahlbau</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65887</link>
      <description>Die Offshore-Windenergie spielt in den kommenden Jahrzehnten eine entscheidende Rolle für die Erreichung eines kohlenstoffdioxidfreien Industriesektors. Allerdings haben Gründungsstrukturen für Offshore-Windenergieanlagen einen erheblichen Einfluss auf den gesamten Installationsprozess und bringen sowohl technische als auch regulatorische Herausforderungen mit sich. Die Anwendung von Leichtbauprinzipien im Stahlbau, beispielsweise durch lastauflösende Tragstrukturen in Jacket-Gründungen, bietet ein großes Potenzial zur Reduzierung des Ressourcenverbrauchs, insbesondere des Stahlbedarfs.&#13;
&#13;
Dieser Vortrag befasst sich mit der vollständigen Digitalisierung von schweißtechnischer Fertigung und Prüfung, wodurch eine vollautomatisierte Produktion sowie eine datengetriebene Qualitätsbewertung von Rohrknoten ermöglicht werden, die wesentliche Komponenten von Jacket-Gründungen darstellen. Darüber hinaus wird der Zusammenhang zwischen Nahtgeometrie und Ermüdungsfestigkeit untersucht, wobei bionische Konstruktionsprinzipien als Vorbild dienen.&#13;
&#13;
Die Ergebnisse zeigen, dass Rohrknoten unter Berücksichtigung geometrischer Toleranzen vollständig automatisiert geschweißt werden können und dass sich Nahtgeometrien präzise entsprechend Vorgaben herstellen lassen, die beispielsweise aus numerischen Modellen oder anderen Quellen abgeleitet werden. Diese Fortschritte tragen wesentlich zur Steigerung der Ermüdungsfestigkeit und der Lebensdauer von Tragstrukturen für Offshore-Windenergieanlagen bei.</description>
      <author>Andreas Pittner</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65887</guid>
      <pubDate>Wed, 15 Apr 2026 11:16:36 +0200</pubDate>
    </item>
    <item>
      <title>Determination of Hot Cracking Susceptibility Using a Large Scale Modified TMW Test</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65884</link>
      <description>This study examines the susceptibility of two filler materials (T46 6 M M21 1 H5 and G46 4 M21 4Si1, Ø 1.2 mm each) to solidification cracking, using an externally loaded hot cracking test. Although these filler materials are usually not critical in terms of hot cracking in engineering applications, cracking occurs when external loading is applied during welding. This was observed during welding under service conditions, e.g., repair welding of highway bridges under traffic loads. In order to characterize this behavior further, experiments were conducted on highly restrained fillet welds in an overlap configuration with 8 mm thick base material (S355J2 + N, 1.0570). The modified approach of the Transverse Motion Weldability (TMW) test is based on the transverse displacement of the lower plate relative to the welding direction at a controlled speed, corresponding to the induced deformation rate v in the mushy zone, initially set to 0.5 mm/s to initiate a crack and then linearly reduced to 0 mm/s. Gas metal arc welding was employed in this study, investigating energy per unit lengths of 0.8, 1.2, and 1.6 kJ/mm. The objective was to find and validate a critical deformation rate (vcr ), below which solidification cracking stops occurring. Therefore, a new force-based evaluation method is presented. While both filler materials exhibited low susceptibility to solidification cracking under standard welding conditions, an increase in cracking tendency was observed with higher energy per unit lengths. The externally loaded test provides a quantitative assessment of hot cracking susceptibility. The results enhance the understanding of solidification cracking mechanisms and provide valuable insights for welding applications under high restraint, including repair welding of loaded structures such as bridges.</description>
      <author>M. Neumann; Philipp Liepold; K. Hoefer; Arne Kromm; Thomas Kannengiesser; J. Hensel</author>
      <category>conferenceobject</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65884</guid>
      <pubDate>Wed, 15 Apr 2026 11:14:30 +0200</pubDate>
    </item>
    <item>
      <title>Hydrogen embrittlement susceptibility vs. pipeline integrity during in-service welding of repurposed NG pipelines</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65881</link>
      <description>In the near future, hydrogen will be transported from producers to consumers on the large scale exclusively by long-distance transmission pipelines, whereas the vast majority will be converted NG pipelines. Like in the NG grid, welding work on/onto pipelines as part of the “hot-tapping” is unavoidable e.g. for maintenance or in case of grid expansion. Meanwhile, the mere compatibility of low-alloyed pipeline steels under pressurized hydrogen was proven. But for repurposed NG pipelines (in use for decades), the transferability of in-service welding concepts is partially discussed. The reason is that NG does not penetrate the pipeline, whereas hydrogen can show the embrittling effects, which strongly interfere with possible defects in the legacy pipeline. The inner pipeline surface undergoes multiple short-term heating to high temperatures, which accelerates the hydrogen diffusion and increases the solubility. In particular for pipes with small wall thickness, the first welding passes can reach an austenitic transformation close temperature. Hence, the pipeline integrity vs. hydrogen embrittlement (HE) susceptibility is of vast interest, despite testing of the diverse material and thickness combinations is challenging. For the first time, welding experiments on pressurized DN300 pipeline-like demonstrators were conducted at approx. 85 bar hydrogen. For wall thicknesses between 5.6 and 6.3 mm this allowed realistic hoop stresses during welding of approx. 50 % of the individual SMYS. Using newly developed sample extraction routines, it was possible to quantify the hydrogen ingress in the material for both, the weld metal and the HAZ. It turned out that the existing surface oxides effectively limited the unavoidable hydrogen uptake during welding (compared to thermodynamic-based calculations). Hence, HE was unlikely to occur and confirmed by comprehensive NDT during and after welding. Accompanying numerical calculations suggest that the gas flow speed must be decreased during welding to limit the internal cooling effect of the gas on the pipeline weld.</description>
      <author>Kjell Erxleben</author>
      <category>lecture</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65881</guid>
      <pubDate>Wed, 15 Apr 2026 10:49:11 +0200</pubDate>
    </item>
    <item>
      <title>Ai-Driven Documentation Analysis for Safety Assessment of Dangerous Goods Packages</title>
      <link>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65880</link>
      <description>The safety assessment of packages for the transport of radioactive material is a highly regulated and knowledge-intensive process. Regulatory authorities must evaluate complex safety reports that integrate mechanical, thermal, shielding, criticality, and operational analyses, supported by extensive heterogeneous documentation such as drawings, certificates, test results, and inspection records. Although these documents are increasingly available in digital form, they remain largely unstructured and weakly interconnected, requiring manual cross-checking of dependencies and assumptions.&#13;
This paper explores the potential of AI-driven documentation analysis to support regulatory safety assessments in the context of IAEA-regulated transport of radioactive materials. It examines the limitations of conventional digital approaches and introduces a multi-layered architecture based on Retrieval-Augmented Generation (RAG), multimodal document processing, and structured knowledge representations. In particular, the paper argues that standard RAG systems are insufficient to capture the deep interdependencies across safety documentation and proposes the integration of Knowledge Graphs and Graph-RAG techniques to enable traceable, multi-step reasoning.&#13;
Beyond technical feasibility, the paper emphasizes the importance of human-centered design, explainability, and trustworthiness in safety-critical and regulated domains. Concepts such as Explainable AI and Human-in-the-Loop operation are discussed as essential prerequisites for regulatory acceptance and long-term resilience. Finally, implementation challenges and future developments are outlined, including machine-readable standards and continuous compliance validation. The study demonstrates that AI-supported documentation analysis can significantly enhance efficiency, transparency, and robustness of safety assessments, provided that technical innovation is carefully aligned with regulatory, organizational, and human factors.</description>
      <author>Frank Wille; Tobias Gleim; Kutlualp Tazefidan</author>
      <category>conferenceobject</category>
      <guid>https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/65880</guid>
      <pubDate>Tue, 14 Apr 2026 08:36:18 +0200</pubDate>
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