Umwelt-Material-Interaktionen
Filtern
Dokumenttyp
- Vortrag (307) (entfernen)
Sprache
- Englisch (179)
- Deutsch (126)
- Mehrsprachig (2)
Referierte Publikation
- nein (307)
Schlagworte
- Korrosion (22)
- Mikroplastik (22)
- Microplastics (21)
- TED-GC/MS (19)
- Biocides (15)
- Zink (15)
- MIC (14)
- Antimicrobial resistance (13)
- Corrosion (12)
- Atmosphärische Korrosion (11)
Organisationseinheit der BAM
- 4 Material und Umwelt (155)
- 6 Materialchemie (59)
- 4.1 Biologische Materialschädigung und Referenzorganismen (58)
- 7 Bauwerkssicherheit (55)
- 6.6 Physik und chemische Analytik der Polymere (44)
- 7.6 Korrosion und Korrosionsschutz (42)
- 4.3 Schadstofftransfer und Umwelttechnologien (35)
- 1 Analytische Chemie; Referenzmaterialien (34)
- 4.0 Abteilungsleitung und andere (34)
- 4.2 Material-Mikrobiom Wechselwirkungen (32)
(i) Überblick zum aktuellen Stand der Normung und aktuellen Normungsvorhaben im Bereich Ökodesign.
(ii) Vorstellung des Forschungsprojektes (Steigerung der produktbezogenen Energie- und Ressourceneffizienz) vor allem in Hinblick auf Vorhaben die sich auf die Langlebigkeit, Reparierbarkeit und Recyclingfähigkeit.
In recent years, the demand for new and sustainable products has been constantly rising. Especially cementitious materials are known for their high carbon footprint and novel approaches will be needed to counterbalance that. The BAM departments 7.1 (building materials) and 4.0 (Material and the environment) try to improve the sustainability of concrete panels by establishing a biofilm on the weather protection layer. Using an ultra-high-performance-concrete allows the production of very thin facade tiles with a small carbon footprint. Furthermore, the durability of these tiles is expected to surpass the one of “normal” concrete facades and offer the possibility of modular renewing of defective tiles instead of a wall, or even remodeling a whole building. The controlled application of biofilms on facades aims to improve biodiversity, microclimate, and air quality in cities. Furthermore, the greening of typically gray surfaces could improve the mental health of the residents. The project focuses on testing a multiplicity of concrete samples, varying e.g., in roughness or pH. The bioreceptivity is analyzed via laboratory tests, as well as in perennial outdoor experiments.
In dieser Präsentation wurden dem Beirat Umwelt die High-Lights und der weitere Ausblick des Foresight Process MIC vorgestellt. Im Fokus stehen hierbei insbesondere die neu angelaufenen Projekte:
COST Action Euro-MIC
MIC im Endlager
Hydrogen: MIC & Wasserstoffversprödung
Biorezeptivität von Betonoberflächen
Mitigation schwarze Pilze
WIPANO ResTest
Phenotypic heterogeneity in disinfection: sources and consequences for antimicrobial resistance
(2022)
A summary of projects here at BAM which investigate the influence of phenotypic heterogeneity on the outcome of disinfection and the influence on antimicrobial resistance. This presentation was given in the Theory Seminar of the Quantitative and Theoretical Biology group of Prof. Oliver Ebenhöh at HHU Düsseldorf
The role of methanogens in microbiologically influenced corrosion (Mi-MIC) is often neglected, due to 1) low reported corrosion rates and 2) the suspected corrosion product siderite, which is electrically non-conductive. Typically, MIC corrosion studies are carried out using batch cultures, which did not represent the dynamic conditions, i.e. pipeline and provide insufficient information on the overall corrosion potential.
We established a unique approach, a multiport flow column (MFC), to simulate pipeline conditions and obtained 10-times higher corrosion rates than previously published. Our result showed that testing procedures have a large impact on the corrosive potential of methanogens. We found strong indications with a combination of ToF-SIMS, SEM-EDS and FIB-SEM analyses that siderite is not the sole corrosion product. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of other environmental parameters (e.g. pH) on Mi-MIC.
Microbiologically influenced corrosion (MIC) is a now well-known challenge and affects industry, society and infrastructure. For a long time, the impact of methanogen-induced MIC (Mi-MIC) was underestimated. This was mainly due to the rather low published corrosion rates and the presumed corrosion product siderite, which is not electrically conductive. In our laboratory, we were able to show that this trivialization or underestimation of Mi-MIC was due to the nature of the testing. The static systems used so far do not provide environmentally relevant information about the corrosion rate and the corrosion product, especially for methanogens
To further illustrate the importance of the environment on the MIC process, we established a multiport flow column (MFC), to simulate the natural environment. With this method, and in contrast to published results using the static conditions, we obtained ten times higher corrosion rates. We analyzed the corrosion products with a combination of techniques, like ToF-SIMS, SEM-EDS and FIB-SEM, and found strong evidence that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron and lacked on carbon-related species. It is hypothesized that methanogens may have influenced the nucleation process of siderite, converting bicarbonate into carbon dioxide for methanogenesis. This results in increased localized corrosion and reduced siderite formation. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate etc.) on Mi-MIC and the subsequent impacts on corrosion rates and the corrosion products.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
Corrosion is a very expensive and serious problem in the different industry sectors, eg. Petroleum-, On- and off-shore, infrastructure. It is estimated that 20% of all corrosion damage is caused by microorganisms or microbiologically influenced corrosion (MIC). Several microorganisms are known to cause corrosion, including sulfate-reducing bacteria, nitrate-reducing bacteria, methanogens etc. For several years, methanogens were regarded as a mild corroder (~0.065 mm/yr), largely due to a lack of detailed investigation on the corrosion mechanism under real-environment simulated conditions. Resulting in the common belief that siderite, a non-conductive compound, is the sole corrosion product (CP) of methanogen-induced MIC (Mi-MIC).
To simulate natural environmental conditions, we developed and introduced the multiport flow column system (MFC), a multi-sectional corrosion flow-cell. Using the MFC, we obtained ten times higher corrosion rates than previously reported. With a combination of several analytical techniques, such as ToF-SIMS, SEM-EDS and FIB-SEM, we found strong indication that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contained phosphorus, oxygen, magnesium, calcium and iron. The differences in the CP between static and dynamic environments demonstrated the impact of testing procedures on the corrosive potential of methanogens. To further verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate) on Mi-MIC.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
Der Fachbereich 7.6 untersucht seit einiger Zeit an Auslagerungsständen auf dem Testgelände in Horstwalde Korrosion im maritimen Bereich. Im Moment läuft das System mit künstlichem Meerwasser und simuliert die Bewitterung von Metallproben unter angenäherten klimatischen Bedingungen ähnlich zum natürlichem Habitat. Im Laufe der Zeit konnte nicht intendierter mikrobieller bewuchs beobachtet werden. Es stellte sich die Frage, welche Mikroorganismen vorlagen und ob diese einen Einfluss auf die Korrosionsuntersuchungen haben könnte. Aus diesem Grund wurden 16S-rRNA Untersuchungen durchgeführt welche alle drei Domänen des Lebens widerspiegeln Bakterien, Archaea und Eukaryoten. Es konnte gezeigt werden, dass über 95% der vorliegenden Biomasse Grünalgen waren, die durch Licht Eintrag in den Container Photosynthese betrieben und dadurch an Biomasse zunahmen. Des weiteren konnten Bakterien detektiert werden, welche in der Regel halophilen und aeroben Habitaten zu finden sind. Allerdings wurden auch Sulfat reduzierende Bakterien (MIC) detektiert, wenn auch in einem geringen prozentualen Anteil. Es muss allerdings Berücksichtigt werden, dass die mikrobielle Zusammensetzung sich im Laufe der Zeit weiter ändern kann. Als Ursprung der Biomasse wird, das künstliche Sediment vermutet. Außerdem wäre es für zukünftige Experiment denkbar, das System mit echtem Sediment aus dem marinen Habitat anzuimpfen.
Der konstruktive Leichtbau erfordert den zunehmenden Einsatz hochfester Feinkornbaustähle mit Streckgrenzen bis zu 1300 MPa. Um darüber hinaus Schweißzeit, Schweißnahtvolumina und Schweißkosten zu minimieren, kam es zur Entwicklung moderner Lichtbogenprozesse mit erhöhter Abschmelzleistung, wie bspw. dem modifizierten Sprühlichtbogen. Das Schweißen mit modifiziertem Sprühlichtbogen bietet die Möglichkeit, schmalere Nahtfugen bzw. kleinere Nahtöffnungswinkel zu schweißen. Mit zunehmender Festigkeit der Baustähle steigen allerdings die Anforderungen an die schweißtechnische Verarbeitung. Hochfeste Feinkornbaustähle weisen ein erhöhtes Risiko gegenüber der wasserstoffunterstützten Kaltrissbildung auf. Diese Werkstofftrennungen entstehen unter gemeinsamer Wechselwirkung von lokalem risskritischem Gefüge, lokal erhöhter Wasserstoffkonzentration und lokal erhöhter Beanspruchung bzw. Dehnung. Untersuchungen haben gezeigt, dass der Einsatz des modifizierten Sprühlichtbogens in Verbindung mit schmalen Nahtfugen zu erhöhten Wasserstoffkonzentrationen im Schweißgut führt. Die vorliegende Arbeit gibt einen Aufschluss hinsichtlich der Kaltrissempfindlichkeit des vergüteten, hochfesten Feinkornbaustahls S960QL anhand der durchgeführten Kaltrissprüfung mittels selbstbeanspruchenden TEKKEN-Tests. Dazu wurden die Nahtöffnungswinkel der Prüfnähte zwischen 30° (Einsatz des modifizierten Sprühlichtbogens) und 60° (Einsatz des konventionellen Übergangslichtbogens) variiert. Ferner wurde die Wirksamkeit einer Nachwärmprozedur aus der Schweißwärme heraus zur Vermeidung der wasserstoffunterstützte Kaltrissbildung untersucht. Die Ergebnisse weisen in allen Proben (ohne Nachwärmung) Kerbrisse auf, welche als Kaltrisse identifiziert werden konnten. Durch eine Nachwärmung unmittelbar nach dem Schweißen können diese gänzlich vermieden werden. Das Schweißgut mit modifizierten Sprühlichtbogen weist die höchsten mittleren Wasserstoffkonzentrationen auf. Ferner zeigt das Schweißgut unter reduziertem Nahtöffnungswinkel eine vermehrte Mikrorissbildung auf.
Mikroplastik findet sich in Ozeanen, Seen, Flüssen und Bächen. Es kann in unserem Boden, in der Luft und sogar in Organismen nachgewiesen werden. Jedes Jahr werden weltweit Millionen Tonnen freigesetzt. Doch wo und wie landet Mikroplastik in der Umwelt? Und wie können wir diese winzigen Partikel nachweisen?
Antimicrobial surfaces have broad use in multiple settings including touch surfaces in hospitals, implanted devices, or consumer products. Their aim is to support existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which might drive the evolution and spread of antimicrobial resistance. In my presentation, I will highlight the risks and knowledge gaps associated with resistance on antimicrobial surfaces by different processes including evolution by de novo mutations and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed onto antimicrobial surfaces. The latter process has the potential to select for antibiotic resistance via cross-resistance between traits that confer resistance to both the antimicrobial surface coating and antibiotics. Conditions in which antibiotics and antimicrobial coatings are present simultaneously (e.g. implants) will lead to more complex interactions that can either result in the selection for or against antibiotic resistance. We mapped these interactions between several antimicrobials and antibiotics on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological (i.e. synergy and antagonism) and evolutionary (i.e. cross-resistance and collateral sensitivity) combination effects. Understanding these interactions opens the door to tailor therapeutic interventions to select against resistance. In additions, we need new methods and translational studies that investigate resistance development to antimicrobial surfaces under realistic conditions. Therefore, I will present recent developments in our lab on the development of such a method based on existing efficacy standards.
Die Untersuchung altlastverdächtiger Flächen umfasst viele einzelne Schritte von der Probenahme über die Probenvorbehandlung bis hin zur eigentlichen Analyse, die zur Ergebnisunsicherheit beitragen. Beim Vergleich der Ergebnisse mit Bewertungsmaßstäben, um Entscheidungen zur Bewertung von Altlasten zu treffen, sind diese Faktoren zu berücksichtigen. Die Rolle von verschiedenen Unsicherheitskomponenten wird mit Blick auf Elutionsverfahren diskutiert.
Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
Microbiologically Influenced Corrosion (MIC) is a phenomenon that is increasingly becoming a problem
for the society. MIC describes the negative effects a material can experience due to the presence of
microorganisms. In Europe, several research groups/ other industrial stakeholders are already dealing with
MIC. Unfortunately, the discussions are fragmented and the exchange of information is limited. A true
transdisciplinary approach is hardly ever experienced, although this would be logical for this
material/biology related challenge.
USA, Canada and Australia have strong networks, and develop methods, prevention measures and
standards, which Europe is forced to use, since nothing similar exists for a network and combined
knowledge to design them according to european standards. This makes Europe extremely dependent and,
in some cases, the potential measures or standards cannot been used because the suggested solutions
are prohibited by European laws (e.g. use of biocides).
Therefore, it is important to initiate a new European MIC-network. Europe needs to combine the efforts as
experts in different fields and develop prevention measures according to the European rules, in close
cooperation with industry and plant operators and owners of critical infrastructure. This COST Action will
provide the necessary interaction and communication, knowledge sharing, training of personnel and of
researchers of different disciplines. This will bring Europe to a leading role in this process, bringing ideas on
an equal level with other nations, considering the values which are important for Europe and attitudes (e.g.environmental protection) and representing greater protection for people, property and the environment.
The main aim and objective of the Action is to , in the context of MIC-research/control, encourage a
fluent/synergistic collaboration/communication, closing the gap between materials scientists, engineers,
microbiologists, chemists and integrity managers to encourage sufficient interaction between academia and
industry. This Action will create a common MIC-Network, including the important stakeholders.
The latest ICP-MS technology - ICP-ToF (time of flight)-MS – enables the analysis of the multi-element fingerprint of individual cells. The interface between material and environmental analysis thus receives special attention, e.g., when considering corrosion processes. Microbiologically influenced corrosion (MIC) is a highly unpredictable phenomenon due to the influence of the environment, microbial communities involved and the respective electron source. However, the interaction pathway between cells and the metal surface remains unclear. The development of the MIC-specific ICP-ToF-MS analytical method presented here at the single cell level, in combination with the investigation of steel-MIC interactions, contributes significantly to progress in instrumental MIC analysis and will enable clarification of the processes taking place. For this, a MIC-specific staining procedure was developed. It allows the analysis of archaea at a single cell level and provides information about the interaction of the cells with the staining agent which is extremely scarce compared to other well characterized organisms. Additionally, the single cell ICP-ToF-MS is used for the analysis of archaea involved in MIC of steel. Hence, the possible uptake of individual elements from different steel samples is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials.
Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms, often with enhanced resistance towards antimicrobial treatment and established cleaning procedures. On e.g. medical implants, in water supply networks or food-processing industry, biofilms can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. Nowadays, the emergence of resistances because of extensive usage of antibiotics and biocides in medicine, agriculture and private households have become one of the most important medical challenges with considerable economic consequences. In addition, aggravated biofilm eradication and prolonged cell-surface interaction can lead to increased biodeterioration and undesired modification of industrial and medical surface materials. Various strategies are currently developed, tested, and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics.
In this study, contact-less and aseptic large-area short or ultrashort laser processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials such as titanium-alloy and polyethylene terephthalate (PET). The laser processed surfaces were subjected to bacterial colonization studies with Escherichia coli test strains and analyzed with reflected-light and epi-fluorescence microscopy. Depending on the investigated surfaces, different bacterial adhesion patterns were found, ranging from bacterial-repellent to bacterial-attractant effects. The results suggest an influence of size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself, emphasizing the potential of laser-processing as a versatile tool to control bacterial surface adhesion.
Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Sunlight-associated stresses are however multiple: high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses. Ascomycota dominating light-flooded habitats accurately sense and respond to changes in light using it as a cue to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships. Two species from two light-flooded habitats – phyllosphere and sun-exposed solid surfaces – were analysed for their photoreceptor distribution.
In both habitats phototroph-associated and black [dihydroxynaphthalene (DHN) melanin-containing] fungi are prevalent. This diversity was sampled with the plant-associated fungus Botrytis cinerea (Leotiomycetes), while Knufia petricola (Eurotiomycetes) was included as a typical biofilm-former on sun-exposed solid surfaces e.g. rocks, building facades, roofs, and solar panels. The analysis has shown that genomes of black fungi contain more photoreceptors than animal pathogens and saprophytes such as Aspergillus nidulans and Neurospora crassa1,2. B. cinerea that causes the grey mould disease by infecting the above-ground parts of more than 200 dicots has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts1.
Rock-inhabiting Dothideomycetes and Eurotiomycetes including Knufia petricola possess equal numbers of photoreceptors along with the same set of protective metabolites i.e. melanin, carotenoids and mycosporines2. This similarity between black fungi from plant and rock surfaces suggests that photoperception and -regulation are important for sun-stressed fungi that receive nutrients through cooperation with phototrophs. CRISPR/Cas9-based genetic tools for manipulating K. petricola were established3 and are currently used for elucidating the functions of the different photoreceptors in the biology of rock-inhabiting fungi.
This work was supported by the grant SCHU 2833/4-1 from the German Research Foundation (DFG) and internal funds of the BAM.
Development of a laboratory method to assess resistance development of microorganisms to biocides
(2021)
Bacteria are exposed to biocides through surface disinfection or by antimicrobial surfaces. These stressful environments provide a strong selective pressure for bacteria to adapt. Here, we describe the development of a laboratory method to assess adaption of bacteria by resistance development in response to surface disinfection and antimicrobial surfaces.
Development of a laboratory method to assess resistance development of microorganisms to biocides
(2021)
Bacteria are exposed to biocides through surface disinfection or by antimicrobial surfaces. These stressful environments provide a strong selective pressure for bacteria to adapt. Here, we describe the development of a laboratory method to assess adaption of bacteria by resistance development in response to surface disinfection and antimicrobial surfaces.
Antimicrobials can exert specific physiological effects when used in combination that are different from those when applied alone. These effects include physiological effects (i.e. synergy, antagonism and suppression) as well as evolutionary effects on the selection of resistant strains (i.e. cross-resistance and collateral sensitivity). While combination effects have been extensively mapped for antibiotic-antibiotic combinations, the combination effects of antibiotics with antimicrobials used as biocides or antiseptics have not been systematically investigated.
Here, we investigated the physiological and evolutionary consequences of combinations of antibiotics (meropenem, gentamicin and ciprofloxacin) and substances used as biocides or antiseptics (octenidine, benzalkonium chloride, cetrimonium bromide, chlorhexidine, povidone-iodine, silver) on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological combination effects with synergy occurring 6 times and antagonism occurring 10 times. The effects are specific to the antibiotic-biocide combination with meropenem showing a tendency for antagonism with biocides (6 of 7), while gentamicin has a tendency for synergy (5 of 7). A particular strong antagonism is apparent for the meropenem-chlorhexidine combination, for which we conducted an in-depth study on the underlying molecular mechanism using RNASeq. Moreover, we find widespread effects of the biocide-antibiotic combinations on selection of P. aeruginosa strains resistant to the antibiotics, including cross-resistance and collateral sensitivity.
In conclusion, antibiotics and biocides or antiseptics exert physiological and evolutionary combination effects on the pathogen P. aeruginosa. These effects have consequences for the efficacy of both types of substances and for the selection of antimicrobial resistant strains in clinical applications with combined exposure (e.g. wound care, coated biomaterials).
Monitoring von Mikroplastik
(2021)
As more industrial interests focusing on using salt caverns and repurposed gas or petroleum reservoirs for alternative fuel storage, i.e. CO2/H2, the question raises whether microorganisms may impact the infrastructure, gas purity and storage condition over time.
Environments with high salinity (> 1.5 Meq of NaCl) are resided by halophiles (salt-loving microorganisms). To compensate for the intensive osmotic stress, they have resorted to two main adaptation strategies: 1) production of compatible solutes and 2) accumulation of intracellular KCl. Microbial community analysis of several high salinity environments revealed a number of recurring genera, including Halomonas and Halanaerobium. However, the impact of halophiles on the overall integrity and stability of the storage facilities remain largely unknown.
To evaluate the suitability and stability of saline storage facilities, several model halophilic microorganisms, such as members of Halomonas, will be selected as testing subjects. First, the impact of halophiles on the infrastructure will be determined using an integrative approach by combining a number of techniques, including electrochemistry, TOF-SIMS, SEM/FIB/EDS and FIB-TEM. Second, the abilities of halophiles to alter the fuel composition (i.e. increase/decrease the fractions of H2) will be monitored using gas chromatography by growing them under high pressure.
As a result of climate change and the accompanying mandatory shift to renewable energy resources, microorganisms will continue to play an important role in the energy sector, both to their benefit and detriment. Thus, it is important to achieve a certain level of understanding regarding the activities and mechanisms of halophiles prior to large-scaled excursions.
Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
For centuries, churches, secular buildings and museums have been furnished with valuable works of art. Many works of art are UV- and light-sensitive. It is well known that especially UV radiation causes damage and discoloration in paintings, textiles, plastics, wood and other materials. In particular, the wavelengths between 280 and 410 nm cause color changes, embrittlement or destruction of e.g. plastics over time. Therefore, strongly UV-absorbing glasses are advantageous for architecture and are necessary for the protection of cultural assets. As restorers in all disciplines become more and more aware, the demands placed on buildings and their furnishings in terms of climate are becoming increasingly detailed and precise. The aim in each case is to preserve the valuable artwork.
For some years now, the industry has been offering the protection of cultural objects by installing special UV-protective glasses. Currently, UV protection for church buildings is realized by laminated safety glass equipped with appropriate UV-protective plastic films. Technically, this always means a second pane of glass in front of the windows, which is installed outside the building. This creates climatic gaps that are difficult to control and deterioration due to ageing effects can be expected. At the same time, this protective glazing is not invisible and has a considerable aesthetic influence on the interior and exterior appearance of the building. Meanwhile, the preservation of historical monuments accepts such aesthetic cuts on buildings in order to protect the artwork in the interior from UV light. To this day, however, the long-term durability of UV protection provided by inserted plastic films is still controversial.
To date the only available alternative on the market is a mouth-blown UV protection glass which uses a so-called overlay to provide UV protection. This shows that UV protection can also be achieved by glasses without plastic films thus realizing an exclusive inorganic protection which normally is more stable than a polymeric one. So far there are not enough studies to prove long-term durability.
The aim of this project is to provide existing glazing or new glazing to be created with a highly transparent layer that ensures this UV-protective filter function below 400 nm. The glass coating is to be applied to the glass over a large area and fired into the surface like a classic ceramic enamel paint with the same technics. In addition, it should be long-term durable in its function. It means, that the glass has to be fused at temperatures below 630 °C during the firing process, its chemical durability has to be high, its coefficient of thermal expansion has to be as close as the one of the substrate (usually float glass) and the glass has to absorb the UV-radiation within a thin thickness (thinner as 100 µm).
In this project, the long-term durability of commercial UV-protective glasses is examined. New low melting glasses containing UV-absorbing ions are being developed. Their UV-absorption as a thin layer is analyzed as well as their chemical durability and their thermal properties.
We are grateful to BMWI for the financial support in the frame of the Central Innovation Programme for SMEs (ZIM).
Der Vortrag wurde im Rahmen der Abschlusskonferenz des Forschungsschwerpunktes "Plastik in der Umwelt" des BMBF gehalten. Er fasst die Ergebnisse des Verbundprojektes RUSEKU zusammen. Es wurde die Herstellung verschiedener Testmaterialien für die Mikroplastik (MP) Analytik beschrieben. Im weiteren geht es um verschiedene Ansätze MP kostengünstig und schnell zu detektieren, z.B. mit Nahinfrarotspektroskopie. Nanoplastik konnte mit der Transmissionselektronenmikroskopie sichtbar gemacht werden. Für die praxisnahe Beprobung von Gewässern wurde die Fraktionierte Filtration entwickelt. Integrale Beprobungen können mit dem Sedimentationskasten erfolgen. Als Beispiele für die Beprobung realer Gewässer wurde das urbane Abwassersystem Kaiserslautern, Getränkewasser und Waschmaschinenwasser gezeigt.
Biodiesel (FAME) from rapeseed is an environmentally friendly alternative to common fossil fuels. It is also suitable to serve as blending component to fuels like heating oil. If the fuel composition is changed, materials compatibility must be guaranteed. Adding polar biodiesel to nonpolar heating oil, changes the blend’s solvency and might cause swelling, extraction and solvation of polymers.
The objective of this research was to investigate the compatibility of polymeric materials, which are commonly used for components in middle distillate facilities, along with blends of heating oil and 20 % biodiesel (B20). For this propose, ACM, HNBR, FKM, PE, PA 6, POM, PUR and PVC were exposed to heating oil and B20 for 42 and 84 days at 40 °C. In addition, the polymers HNBR, FKM, PA, POM and PVC were also exposed at 70 °C. Furthermore, the resistance of polymers in eight-year aged B10 at 40 °C was evaluated. Ageing of biodiesel increases acidity which might propagate polymer corrosion.
The materials were evaluated as resistant, if the loss in tensile properties (tensile strength and elongation at break) and Shore hardness remained under 15 % compared to the initial unexposed material values. For investigations under compressed conditions, the compression set was determined for specimens of ACM, FKM and HNBR after exposure in heating oil B0 and B20 for 3,7,14, 28, 56 and 90 days at 40 °C according to ISO 815-1.
It was found that the resistance in B20 at 40 °C was given for all tested polymers except PUR. In the 8 years aged B10, PUR and POM were not compatible and ACM just conditionally compatible. At 70 °C, FKM and PVC were resistant in B20, whereas HNBR and PA 6 were not compatible. Swelling occurred for the elastomers ACM, HNBR and PUR.
Rock-EATING FUNGI - Genetic Dive into the Biology of the Microcolonial Black Fungus Knufia petricola
(2021)
Microcolonial black fungi are a group of ascomycetes that exhibit high stress tolerance, yeast‑like growth and constitutive melanin formation. They dominate a range of hostile natural and man‑made environments, from desert rocks and salterns to dishwashers, roofs and solar panels. Due to their slow growth and a lack of genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We chose to address this gap by genetically engineering the rock‑inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales), a species that exhibits all characteristics of black fungi. The state‑of‑the‑art genetic toolkit, together with the annotated genome sequence of strain A95, firmly established K. petricola as a model for exploring microcolonial black fungi.
A new approach towards performance-related design and scientific evaluation of joint sealing systems
(2020)
While there is a permanent improvement of concrete pavement mixtures and pavement construction types over the last decades, the state-of-the-art joint sealing materials and joint constructions seem to stagnate on an antiquated empirical level. This status has been reaffirmed in the latest European standard.
The consequences in the motorway network due to unsatisfying capability and durability of joint sealing systems are unacceptable. In addition, inadequate traffic performance (noise emissions, roll-over comfort) and traffic safety losses in the joint area of concrete pavements are existing challenges. These deficits and weaknesses reflect a demand for joint sealing materials and constructions whose approval requirements take functional aspects into account. Furthermore a sufficient analysis of decisive loads and a practice-oriented method to evaluate the requirements towards performance and durability is still missed.
In this contribution decisive loads to German highways are analyzed. The design of test specimen for representative functional testing of joint sealing systems is discussed. The focus is on the geometry of the test specimens and the used concrete mixture. Finally, a new approach for a function-orientated test concept that considers representative load functions is presented. The potential of this approach to validate the durability and capability of various joint sealing systems is also presented using an example.
Das Jahr 2020 war vor allen Dingen von der Pandemie geprägt, die alle Bereiche des Lebens und Arbeitens beeinflusst hat und immer noch beeinflusst. Dies hat sich auch auf verschiedene Maßnahmen im Zusammenhang mit zugelassenen Produkten ausgewirkt. In diesem Zusammenhang sollen die Punkte kurz aufgeführt werden. Des Weiteren soll aufgezeigt werden, wie bei der Bearbeitung der Richtlinien, der Zulassungstätigkeit und Beurteilung der Produkte an der BAM und im Fachbeirat vorgegangen wird. Darüber hinaus soll noch einmal kurz auf die Entlassung aus der Nachsorgephase eingegangen werden. Am Ende sollen verschiedene aktuelle Fragestellungen des Fachbeirat aufgezeigt werden.
Kleinere und mittlere Unternehmen agieren heutzutage in einem globalen Umfeld, wodurch diese zu Elementen einer komplexen Wertschöpfungskette werden. Der zunehmende Anstieg der Preise für industriell essenzielle Ressour-cen, wie Primärenergie und Rohstoffe, sowie sich ausweitende klimapolitische Restriktion führen zur Notwendigkeit, die Wettbewerbsfähigkeit durch innovative und ökoeffiziente Fertigungsprozesse langfristig zu sichern. Rahmenbe-dingungen zu schaffen, welche die Positionierung nachhaltiger Produkte und Prozesse innerhalb globaler Wert-schöpfungsketten ermöglicht, ist daher ein wesentliches Ziel der deutschen Industriepolitik [1, 2].
Im Rahmen dieses Beitrages werden aktuelle Forschungsarbeiten zur Bewertung der Umweltwirkungen der schweiß-technischen Fertigungskette anhand ausgewählter Schmelzschweißverfahren unter Berücksichtigung vor- sowie nachgelagerter Fertigungsschritte dargestellt. Das hierzu notwendige Element zur Analyse der Fertigungsprozesse ist die Ökobilanzierung - eine weit verbreitete und standardisierte Methode zur Abschätzung der Umweltwirkungen eines Produktes oder Prozesses. Hierbei stellt die Sachbilanzierung, d.h. die Ermittlung sämtlicher relevanter Ener-gie- und Ressourcenverbräuche während der schweißtechnischen Fertigung, aufgrund des hohen Dokumentations-aufwandes sowie Ableitung assoziierter Wirkkategorien das größte Hindernis für eine Etablierung und Akzeptanz der Ökobilanzierung in der Praxis dar. Gleichwohl wird seitens Unternehmen, welche als Zulieferer von OEM’s agieren, die Dokumentation des fertigungsspezifischen CO2-Verbrauches gefordert.
Ein weiterer Aspekt der Arbeiten beinhaltet folglich Methoden zur automatisierten Erfassung von schweißtechnischen Produktionsdaten sowie deren Nachverfolgbarkeit aufzuzeigen. Anhand unterschiedlicher Schweißverfahren werden die aus den Produktionsdaten abgeleiteten Energie- und Ressourcenverbräuche automatisiert in den relevanten Umweltwirkungen überführt. Die analysierten Schweißprozesse umfassen dabei ein breites für kmU relevantes Spektrum. Durch die softwareseitige Bereitstellung der aufgestellten Umweltprofile ist der Anwender in der Lage, Schweißprozesse unter ökologischen Aspekten zu bewerten und die effizienteste Variante zu identifizieren.
A study on building vibrations has been performed by finite element calculations. Family houses, multi-storey residential buildings, office buildings and office towers have been modelled in detail. The frequency-dependent response due to a free-field excitation has been evaluated for walls, columns and floors. The ratio of building amplitudes to free-field amplitudes starts with uB/u0 = 1 at zero frequency and is usually lower than 1 at 50 Hz, the end of the frequency range considered here. In between, amplifications occur due to several reasons. There are „soil resonances“ where the whole building is vibrating on the compliant soil, “column resonances” where the upper storeys are vibrating on the compliant columns, and the “floor resonances” where the floors are vibrating excited by their supports. Results are presented for all building types, but a special focus is set on office buildings. A parameter study shows the influence of the stiffness of the soil, the number of storeys, and the width of the building. It has been found that the “soil resonance” is strongly modified by the low-frequency floor resonances for the normal office building. The main resonance of a twenty-storey office tower is determined equally by the “soil mode” and the “column mode”. It is an important observation for these office buildings that the resonances can differ for different parts of the building such as the centre, the edge, the corner, and the core of the building. This leads to non-uniform vibration modes across the building, which look like another type of “floor resonance” and which have been observed in several real building projects. Experimental results will be shown which can confirm the calculated phenomena.
Der Vortrag berichtet über die Auslagerung von Standardproben nach DIN EN ISO 9223 bis 9226 aus Zink, Stahl, Kupfer und Aluminium auf den verschiedenen atmosphärischen Bewitterungsständen der Bundesanstalt für Materialforschung und -prüfung (BAM). Im Vortrag werden die Masseverluste, Korrosionsgeschwindigkeiten und Korrosivitätskategorien der Standardproben im freibewitterten und überdachten Bereich nach einem Jahr vorgestellt und Unterschiede hinsichtlich der Atmosphärenbedingungen aufgezeigt. Freibewitterte Proben zeigen dabei deutliche Unterschiede hinsichtlich ihres Korrosionsverhaltens im Vergleich zu überdachten Proben. Die ermittelten Korrosivitätskategorien sind sowohl standort- als auch materialspezifisch.
Das korrosionsverhalten von metallenen Werkstoffen in Erdböden besitzt unter Betrachtung der Dauerhaftigkeit sowie aus wirtschaftlichen Gesichtspunkten eine entscheidende Bedeutung. Um zu überprüfen, ob ein metallener Werkstoff für eine bestimmte Bodenklasse geeignet/ beständig ist, müssen oftmals elektrochemische Korrosionsuntersuchungen im Boden durchgeführt werden. Da sich natürliche Böden aufgrund ihrer organischen Bestandteile mit der Zeit verändern, sind die Ergebnisse der Korrosionsuntersuchungen nicht reproduzierbar.
Ziel dieser Untersuchungen ist es, künstliche Böden herzustellen, die aufgrund ihrer Eigenschaften (Bodenparameter) Bodenklassen der DIN 50292-3 zuzuordnen sind um zukünftig reproduzierbare Ergebnisse im Labor generieren zu können.
Designing the performance of geogrids in reinforce soil constructions usually does not consider long-term behavior and possible failure modes of junctions between longitudinal and transverse ribs. How could behavior of junctions be included? To which extend is it necessary? On the conference Geo-Chicago 2016, Swan and Yuan presented an ultimate limit state equation for the short-term material resistance of junctions. We discuss limitations and suggest improvements to include long-term behavior of junctions. Nevertheless, the approach applies only to a specific mode of shear-tensile failure of junctions and only to strictly rigid geogrids. A new design concept presented in the same year by Jacobs on the conference GeoAmerica for the special case of the anchorage of geogrids, which reinforce capping system on long and steep slopes of landfills, tried to overcome these drawbacks. We discuss the aspects of this concept related to the long-term behavior of junctions and the interplay between the load applied to junctions and the flexibility of longitudinal ribs. This interplay and the long-term junction strength determine the long-term behavior of geogrids.