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Analysis of Methods for Predicting H2 Sensor Responses
No full textHydrogen (H2) is crucial for replacing fossil fuels and achieving net-zero emissions, but its flammability and explosiveness pose safety challenges. Rapid H2 leak detection is essential for triggering emergency accidents. However, H2 sensor response is constrained by material properties and gas flow dynamics, causing response and detection delays. Our current study explores various available algorithms for H2 sensor response prediction from early responses with a small time window, accelerating leakage detection. Our findings identify the most efficient algorithms for real-time implementation, enhancing H2 safety systems
High-throughput Computational Screening With Chemical Heuristics, Workflows, and Machine Learning
No full textWithin my talk, I have introduced the audience to high-throughput materials discovery with the help of workflow tools, machine learning and chemical heuristics. I started with a general introduction to the Materials Project software infrastructure and databases such as the Materials Project and NOMAD. Then, I dived into machine learning tasks relying on chemical bonding information, machine-learned interatomic potentials, and experimental data. Target properties of the machine-learning tasks were thermal properties, phonons, magnetism and synthesizability
Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration
No full textMeasuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization
Standardized Chemical Composition Analysis of Graphene Oxide Flakes with SEM/EDS and XPS Works Reliably
No full textReliable quantification of the chemical composition of graphene-related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended in projects at standardization bodies. The parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present. In this contribution, for the first time, the capability of SEM/EDS to reliably quantify the O/C ratio in a well-characterized graphene oxide (GO) material is evaluated. The robustness of the SEM/EDS results under various measurement conditions is tested by comparison to the established XPS analysis.
A crucial step is the sample preparation from liquid suspension with GO flakes onto a substrate for analysis with both EDS and XPS. It is demonstrated that if a closed and enough thick drop-cast spot is deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterizing EDS result in very similar elemental composition of oxygen and carbon. Hence, the theoretical, expected O/C atomic ratio values for pure GO of ~0.5 are achieved with both methods. Further, the effect of untight deposited material causing co-analysis of the silicon substrate, is evaluated for both methods, XPS and EDS. Note that all the EDS results in this study have been quantified standardless.
The standard measurement procedure including the GO material considered here as a candidate reference material will make a significant contribution to analyse reliably the chemical composition of GR2M with SEM/EDS as one of the most widely used methods in analytical laboratories
Vitrimers – new golden child of polymers?
No full textVitrimers represent an innovative and promising class of sustainable materials poised as an alternative
to conventional epoxy thermosets within the framework of the circular economy. Based on covalent
adaptive networks (CANs), vitrimers exhibit dynamic bon d rearrangements upon external stimuli,
endowing them with unique properties such as shape memory, self healing, and recyclability. These
pioneering materials combine the robust mechanical behavior of classic lightweight thermosets with
the inherent mallea bility of thermoplasts, making them highly attractive for next generation
sustainable material applications.
This study explores the intricate interplay between the nature of CANs and the macroscopic properties
of newly developed vitrimers. The investigated material is a bio based vitrimer consisting of a glycerol
triglycidyl ether (GTE) resin and a vanillin derived imine hardener (VA). This system represents an ideal
biobased substitute for fossil derived epoxy resins and leverages a catalyst free imine metathesis
mechanism to enable recycl ability.
Despite the advantages of vitrimers, the molecular mechanisms governing their recyclability,
particularly the dynamic exchange reactions, remain poorly understood. To gain deeper insights into
these mechanisms, this study employs a combination of broadband dielectric spectroscopy , neutron
scattering, mechanical spectroscopy, calorimetry, and dynamic thermal investigations. A systematic
approach utilizing both standard and innovative characterization techniques is essential to unravel the
synergistic relationship between molecular behavior, structure, and thermomechanical performance.
This fundamental understanding will help propel vitrimers to the forefront of sustainable material
science, advancing their practical implementation as recyclable polymer systems
Laser Induced Breakdown Spectroscopy (LIBS) for the chemical investigation of concrete - Status of practical application and regulations in Germany
No full textLaser-Induced Breakdown Spectroscopy (LIBS) is an advanced, yet still underutilized, analytical technique that has gained increasing recognition for its potential in evaluating cementitious materials. Over the past several years, LIBS has demonstrated exceptional capabilities in providing detailed insights into the microstructural and chemical properties of concrete, with particular relevance to durability studies and service life assessment.
One of the defining features of LIBS is its high spatial resolution, which enables precise mapping of ion transport processes within the binder matrix. This ability is critical for understanding concrete behavior under diverse environmental and operational conditions, such as chloride ingress, sulfate attack, or carbonation. By allowing the simultaneous detection of multiple elements, LIBS is uniquely suited for investigating complex interactions, including the co-migration of ions. Such comprehensive analyses yield detailed ion ingress profiles, improving the accuracy of key input parameters used in service life models. As a result, LIBS contributes to more reliable predictions of a structure's remaining lifespan and its susceptibility to environmental degradation.
In addition to ion profiling, LIBS is particularly effective in identifying local anomalies that would otherwise not be detected by conventional methods. For instance, LIBS can reveal zones of elevated ion concentration in microcracks or other vulnerable regions, offering critical insights into structural integrity. LIBS supports the assessment of repair processes not only during application but also over long-term monitoring periods, thus contributing to the optimization of rehabilitation strategies.
This presentation showcases a series of practical applications of LIBS in the laboratory analysis of building materials, supported by extensive comparative studies. Case studies highlight LIBS's transformative role in repair planning and decision-making, emphasizing its capacity to revolutionize infrastructure monitoring and maintenance
A decarbonized future requires pipelines for CO2? A brief overview on perspectives and challenges
No full textDespite the use of hydrogen, for example, in various industrial production processes, CO2 emissions are still unavoidable in the medium term. For example, cement, lime and glass production or waste recycling (waste-to-energy plants) will continue to emit CO2 due to the processing involved chemical reactions. Conversely, the chemical industry with its value chains needs CO2 / carbon as a primary raw material for all compounds that fall within the organic chemistry. In this connection, carbon capture utilization (CCU) will play a key role here. In addition to “natural” methods (via reforestation and the dilution of moors), carbon capture storage (CSS) is already playing a major role, for example by injecting it into old natural gas underground caverns. The resulting quantities of CO2 have to be transported on a large scale and similar to hydrogen pipelines, there are concrete plans for CO2 pipeline networks. For this reason, this presentation provides an introduction to the topic and briefly outlines the associated challenges. On the one hand, these lie in the qualification (testing and construction) and especially in the operation of the pipelines with regard to strict monitoring of the gas quality (e.g. carbonic acid corrosion) and in the avoidance of critical service conditions (sudden pressure fluctuations), which can lead to localized condensation. Among other things, this can lead to the lowering of the typically welded low-alloyed steel pipes below the ductile brittle transition temperature (DBTT) and thus can have an impact on pipeline integrity
Current status of monitoring of PFAS release from industrial facilities
No full textIncreasing studies report per- and polyfluoroalkyl substances (PFAS) in the ambient air and emissions from diverse industrial sources. Therefore, a comprehensive framework for characterizing PFAS emissions by identifying source-specific chemical fingerprints, evaluating emission pathways and assessing the impact of remediation technologies is needed. Depending on the type of PFAS, dedicated sampling and analytical procedures are required. Here, also the detection of possible PFAS transformation products, so-called products of incomplete combustion (PICs) are more mobile or toxic, is also of great interest to evaluate these technologies in terms of mineralisation potential and fluorine mass balance
Experimental Investigation of Large-Scale Hydrogen Diffusion Jet Flames
No full textHydrogen is a promising alternative to natural gas in industrial energy applications to limit global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). Most existing data on thermal radiation are based on unsteady flow conditions and/or still air, whereas the experiments carried out here ensure a constant mass flow under realistic free-field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Based on the investigations, empirical equations for modelling jet flames could be derived
Thermoresponsive UCNP@MSN Nanoparticles for Doxorubicin Delivery in Melanoma Cells
No full textUpconversion nanoparticles (UCNPs) possess unique photophysical characteristics, such as excita bility by near infrared (NIR) light, which facilitates deep tissue penetration, multi color emission , long luminescence lifetimes, and an excellent photostability. These features have made UCNPs promising tools for biomedical applications . M esoporous silica nanoparticles (MSNs) functionalized with stimuli responsive nanovalves or specific coatings enable the encapsulation and controlled release of therapeutic agen ts, thereby offering spatiotemporal precision in drug delivery 1 3 ]]. Among drug delivery strategies, photoresponsive systems have attracted growing attention due to their potential for clinical applications . This is especially relevant for melanoma, an aggressive skin cancer with increasing global incidence, for which conventional therapeutic modalities remain largely insufficient in advanced stage 4 In this work, core shell UCNP@MSN nanoparticles were synthetised by coating UCNPs with a mesoporous silica layer, which was subsequently functionalized with thermoresponsive retro Diels Alder nanovalves [ and loaded with the chemotherapeutic agent doxorubicin (DOX). Controlled drug release was effectively achieved under 980 nm NIR i llumination . Treatment with functionalized nanoparticles significantly reduced the viability of melanoma cell lines, with an enhanced cytotoxicity being observed upon combined nanoparticle exposure and NIR illumination . Mechanistic analyses revealed that neither UCNPs nor NIR i llumination alone could induce the production of reactive oxygen species (ROS); however, their combination induced a marked increase in ROS levels in two of the three tested cell lines. Furthermore, this dual treatment promoted substantial apoptotic and/or necrotic responses across all cell models. These findings underscore the potential of UCNP@MSN nanoplatforms, equipped with thermoresponsive ga tes , as efficient photoactivated drug delivery systems for melanoma therapy