Sanitär- und Kommunaltechnik; Umwelttechnik
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Paper des Monats
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Methane emissions are a significant environmental and safety concern, yet many gas tomography systems intended to measure them require manual alignment, reliable high-bandwidth links, or fiducials. We present a lightweight, fully autonomous framework enabling line-of-sight inter-robot Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurements without such constraints. A sensor robot equipped with a gimbal-mounted TDLAS unit tracks a reflector robot bearing an illuminated, color-controllable target. Coarse localization is achieved via RTK-GNSS, with vision-based fine tracking and passive time synchronization handled onboard. The system, based on off-the-shelf Pixhawk controllers and ArduPilot firmware, was validated in a 15m × 7m outdoor trial. Despite GNSS inaccuracies and deliberate occlusion by a methane-filled bag, the system retained lock, recovered from visual loss in under one second, and captured a 2800 ppm·m plume signature. These results demonstrate robust, scalable methane sensing for mobile gas tomography or standalone leak detection. Core components are released open-source to support future deployment.
Size exclusion chromatography (SEC or GPC) is one critical component of polymer analysis to meet the increasing requirements in regulatory context – namely, determination of Mn, as well as oligomers of less than 500 g mol-1 and 1000 g mol-1. The underlying test methods (OECD 118/119 and DIN EN ISO 13885 1 to 3) provide a framework for SEC measurements; however, they lack sufficient specificity to obtain accurate results. Previous SEC round robin tests were mostly performed on homopolymers and did not collect data on oligomer contents.
A new round robin test was initiated and conceptualized within the Task force “Method Evaluation for Polymer REACh (MeEP)”, an initiative of “Industrieforum Analytik” within the German Chemical Society (GDCh). Samples for this study were selected to represent both easy benchmark polymers as well as real-life, industry-relevant polymer materials. Data collection focused on the regulatory requirements.
Distribution of samples, gathering of individual results and evaluation were carried out by BAM. A data summary as initial result is reported here. Further evaluation and interpretation are a part of ongoing research.
In order to create sustainable lifestyles and societies in the long term, sustainability goals must be balanced in terms of the environment, the economy and society. However, these targets are sometimes in conflict with each other and cannot be balanced without compromise. Today, the sustainability debate focuses primarily on balancing environmental/climate and economic targets. Social aspects tend to play a marginal role in the debate. This is also the case in the construction industry, which contributes significantly to global energy consumption and high grey and operational CO2 emissions worldwide. For this reason, research and politics have focused intensively in recent decades on ways to reduce climate emissions while maintaining economic efficiency.
Historically, the focus in construction has been on structural safety. The classic credo in engineering was ‘more is more’. In the context of the climate debate, however, ‘less is more’ often applies, so that engineers and architects today face an economic conflict of objectives between the classic requirements for failure probability and the requirements for sustainable, resource-saving construction, which calls for completely new, much more holistic approaches to material development and structural design. The aim here is to build in a way that is both economical and climate-friendly without compromising structural safety, which is already a complex undertaking.
However, the influence of the use of materials, architecture and construction technology on social aspects is often given much less consideration in the sustainability debate, even though enormous population growth and urbanisation processes are expected in the future, particularly in developing economic areas. This inevitably requires a stronger focus on the socio-economic aspects of construction, especially since, in contrast to many current metropolises, many conurbations in these regions will emerge in areas that are not yet densely populated. This provides freedom for innovative concepts that avoid the mistakes of the past and can consider all aspects of sustainability as largely equal. This freedom enables construction methods and urban concepts that use renewable, circular, local materials to create adaptable, accessible and liveable structures that are equitable, inclusive and fair for society.
This position paper deals with the socio-economic footprint of materials and buildings. It was compiled by an interdisciplinary group of international experts and attempts to develop approaches for effective socio-economic life cycle analysis using similar concepts to those used in environmental life cycle analysis of products and buildings. In contrast to economic analyses or environmental life cycle assessments, which can work with reasonably available and clearly defined units to develop indicators, it is often impossible to determine units for socio-economic indicators, data is more difficult to obtain and there is a lack of benchmarks.
During the discussions, a number of relevant parameters were developed, which can provide clearly quantifiable indicators for socio economic effects. These are related to largely available economic and employment data and consider the distribution of project contracts during implementation and the employment figures associated with project implementation. Particularly in the implementation of large-scale projects involving international investors and financial institutions, ‘(green) compliance value extractivism’ effects can occur, whereby partners from the donor countries are given preference over local project partners. This fraction of the loan flow directly abroad and can no longer serve the local economy to grow. This results in economic follow-up costs, even with lower project costs, which can promote social injustices. The higher the proportion of local companies and employees at engineering levels, the more fairly the construction project serves the local economy.
The use of laser-additively manufactured metallic components in the industrial sector is gaining traction, with the process now entering its application phase. Consequently, the materials are exposed to corrosive microbes, which this study examines in order to determine the implications of this exposure. Specifically, the study examines the exposure of laser powder bed fused AlSi10Mg (PBF-LB/AlSi10Mg) components to sulphate-reducing bacteria in an anaerobic environment. Is the specific PBF-LB microstructure a potential factor in determining or aiding biocorrosion?
A prismatic specimen was exposed to sulphate-reducing bacteria (SRB) for two weeks. The sample was scanned by X-ray computed tomography (XCT) before and after SRB exposure. The two data sets were registered to each other (using the internal void distribution as markers, due to the corrosion of the specimen’s surface) to enable the evaluation of the corrosion damage.
Virtual cuts of the 3D XCT reconstructions show a loss of volume and localised damage. The damage distribution aligns with the hatching pattern of laser exposure from laser powder bed fusion.
The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes.
The demand for compact, high-performance optical components has driven the development of increasingly sophisticated and miniaturized optical elements, often requiring complex and costly fabrication methods. In this study, we propose a cost-effective and accessible methodology for the fabrication of lenses and free-form optics using a commercially available stereolithography (SLA) 3D printer. A systematic characterisation of six transparent photopolymer resins was conducted in terms of their spectroscopic, optical, and morphological properties, i.e., surface and dimensional properties. The evaluation encompassed parameters such as transmittance, autofluorescence, refractive index,
and surface roughness. A straightforward yet resilient printing and post-treatment protocol was formulated, facilitating the fabrication of optical components with over 80% transmittance, minimal intrinsic fluorescence, and surface quality that is compatible with exacting optical applications. The fabricated components demonstrated excellent dimensional fidelity to digital designs and high reproducibility. To demonstrate the versatility of this approach, aspherical, miniaturized, and freeform lenses were designed and integrated into three fluorogenic sensing systems, including oil (strip-based) and chlorine (microfluidic-based) detection platforms, as well as a smartphone-based SARS-CoV-2 biosensor. The integration of customized 3D-printed optics has been demonstrated to enhance signal collection and readout performance, thereby highlighting the potential of this approach to
democratize the rapid prototyping and deployment of miniaturized optical systems. This work
represents a significant advancement in the field of additive manufacturing, particularly in relation to the development of functional photonic devices. Furthermore, it opens new prospects for sensor applications in biosensing, microfluidics, imaging, and integrated optics.
Fecal pollution in water poses significant health risks, especially when contaminated sources are used for drinking and food production. Traditional water quality testing methods are expensive, slow, and require skilled personnel, limiting their accessibility. This work addresses these issues by developing a portable fluorometric assay for the detection of the fecal indicator pigment urobilin (UB). The assay uses silane-functionalized glass fiber strips impregnated with zinc chloride, providing a ‘drop-&-detect’ approach with enhanced fluorescence response mediated by the unique complexation properties of ZnCl2 and UB. This approach allows for the detection of UB at sub-nanomolar concentrations in less than 1 min using a 3D-printed setup with miniaturized optical components powered by a smartphone with its camera as a detector. The results validated with a benchtop fluorometer show the effectiveness of this method. The successful application of this userfriendly, rapid, and sensitive assay to real water samples from three rivers and the influx and efflux of a wastewater treatment plant advances field-based water quality monitoring, meets the WHO’s ASSURED criteria, and supports progress toward the global clean water and sanitation goals.
Detecting nanoplastic particles in environmental samples and biological tissues remains a significant challenge, especially in view of newly emerging polymers, not yet commercially exploited. Fluorescent labeling provides a tagging strategy to overcome this limitation by reducing the detection limit of individual particles, especially for small-sized particles. We present a method for producing labeled nanoparticles (NP/MP) of poly(ethylene terephthalate) (PET) and poly(ethylene furanoate) (PEF), tagged with Alexa Fluor 633 or Alexa Fluor 647. Our preparations used mechanical grinding or solvent-based approaches (confined impinging jet mixing, ((CIJ, precipitation), generating particles with hydrodynamic diameters of 200–700 nm, displaying long-term stability in water of up to 57 days. Stable suspensions with concentrations of the particles ranging from 10 µg/mL (surfactant-free, by solvent mixing) to 5.88 mg/mL (precipitation, containing surfactant) were generated with zeta-potentials from −5 to −50 mV. Characterization of the nanoparticles by SEC, DSC, and XRD showed no significant changes in molecular weight, thermal behavior, or crystallinity via the solvent-based methods, compared to the pristine polymer, highlighting their suitability for producing standardized nanoparticle dispersions. Fluorescence spectroscopy of the Alexa-dye-labeled particles confirmed the successful incorporation of the Alexa dyes, so improving monitoring of their biological profiles of the PEF-MP/NPs. s-SNOM (near field imaging) could identify individual PEF-particles sized ∼200 nm by direct imaging.
Current recycling methods for polymer matrix composites produce short, unoriented carbon fibers, limiting their use to intermediate‐strength applications. A method is therefore needed to recycle fibers while preserving their original length and orientation, enabling a circular economy for carbon fiber composites. This study proposes a novel hierarchical composite designed to retain fiber length and orientation during recycling. Virgin carbon fibers are encased in an insoluble epoxy matrix to form tapes that act as the primary units of the structure. The primary tape matrix shields the fibers from chemical degradation while preserving their alignment throughout recycling. The tapes are then embedded in a secondary recyclable matrix, Elium, a thermoplastic polymer soluble in acetone with mechanical properties comparable to epoxy. The composite is recycled by dissolving the secondary Elium matrix in acetone and recovering the primary tape units with intact fiber length and orientation. The primary units can then be used to assemble new composites. In this study, hierarchical composite laminates underwent recycling up to three times. Their mechanical properties were assessed after each cycle. Laminates with an Elium secondary matrix retained 60%–90% of the mechanical performance of epoxy‐based laminates. Minimal degradation was observed between cycles, and fiber length, orientation, and volume fraction were fully preserved. Pushout tests confirmed that fibers in the primary tapes were sufficiently shielded during the recycling process. These results validate the feasibility of a hierarchical recyclable composite that combines recyclability with high mechanical performance, serving as a proof of concept and providing opportunities for future development.
Aufgrund ihrer einzigartigen molekularen Beschaffenheit werden per- und polyfluorierte Alkylsubstanzen (PFAS) in vielen unterschiedlichen Produkten und Anwendungsgebieten eingesetzt. Da sie generell eine hohe Persistenz aufweisen und je nach individueller Struktur unterschiedlich mobil sind, sind sie mittlerweile in allen Umweltkompartimenten und ubiquitär nachzuweisen. Ihre potenzielle (ökologische) Toxizität birgt dabei erhebliche Umweltrisiken, weshalb PFAS in den letzten Jahren mehr und mehr in den Fokus von Umweltverbänden und -behörden gelangten. Gleichzeitig beschäftigen sich Forschungseinrichtungen mit der möglichst weitreichenden Entfernung aus der Umwelt sowie mit deren (anschließender) Zerstörung.
Im Projekt ER24-4073 „Untersuchung des thermischen Abbaus von PFAS in einer kommerziellen Großanlage zur Verbrennung gefährlicher Abfälle“, welches vom U.S. Department of Defense (DoD ) über das Strategic Environmental Research and Development Program (SERDP) gefördert wird, untersuchen deutsche, australische und amerikanische Partner die Behandlung von PFAS-haltigen Abfallströmen in einer großtechnischen Verbrennungsanlage, um die Einsatzbereitschaft, Machbarkeit und Sicherheit dieser Zerstörungsmethode zu demonstrieren.