4 Material und Umwelt
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- 7 Bauwerkssicherheit (10)
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- 9 Komponentensicherheit (5)
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- 6.6 Physik und chemische Analytik der Polymere (4)
- 5.4 Multimateriale Fertigungsprozesse (3)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (3)
- 8.0 Abteilungsleitung und andere (3)
- 9.3 Schweißtechnische Fertigungsverfahren (3)
- 5.1 Mikrostruktur Design und Degradation (2)
- 5.3 Polymere Verbundwerkstoffe (2)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (2)
- 8.5 Röntgenbildgebung (2)
- 9.0 Abteilungsleitung und andere (2)
- 1.0 Abteilungsleitung und andere (1)
- 2 Prozess- und Anlagensicherheit (1)
- 2.1 Sicherheit von Energieträgern (1)
- 5.6 Glas (1)
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- 7.6 Korrosion und Korrosionsschutz (1)
- 8.4 Akustische und elektromagnetische Verfahren (1)
The earliest known recipes for iron gall inks include four basic ingredients: oak galls – pathological growths of oak leaves; metal salts – usually referred to as vitriol; a binder such as gum Arabic; and water. The final product differs in the elemental composition due to the multitude of recipes as well as differences within the composition of the ink’s ingredients. Nowadays, based on the qualitative and semi-quantitative evaluation of X-ray fluorescence data, it is possible to distinguish inks on the basis of the so-called fingerprint model. The first goal of our study was to determine to what extent the type of XRF spectrometer affects the quality of the ink evaluation. We tested two types of spectrometers, semi-stationary machines equipped with polycapillary focusing optics and a handheld spectrometer with a diaphragm collimator and a relatively big interaction spot.
The second goal was to address the issue of whether the ink composition might be affected by storage in a metal container. The presentation will discuss the role of the spectrometer type in the evaluation of a thin layer material such as ink.
We have also learned that the iron-gall ink composition might depend on the type of vessel in which ink was being stored.
A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning.
Previous research shows that analytical methods based on Diffusive Gradients in Thin films (DGT) provide very good correlations to the amount of bioavailable nutrients and pollutants in the environmental samples. However, these DGT results do not identify which compound of the specific element has the high bioavailability. Using various spectroscopic techniques (infrared, XANES and NMR spectroscopy) to analyze the dried DGT binding layers after deployment could allow us to determine the specific elements or compounds. Nutrients such as phosphorus and nitrogen are often, together with other elements, present as molecules in the environment. These ions are detectable and distinguishable by infrared and NMR spectroscopy, respectively. In addition, XANES spectroscopy allows for the specification of nutrients and pollutants (e.g. chromium) on the DGT binding layer. Furthermore, microspectroscopic techniques make it also possible to analyze compounds on the DGT binding layer with a lateral resolution down to 5 µm2. Therefore, species of elements and compounds of e.g. a spatial soil segment can be mapped and analyzed, providing valuable insight to understand the dynamics of nutrients and pollutants in the environment. Here we will present the advantages and limitations of this novel combination of techniques.
Uninvited and Welcomed Guests in Museums – Biological management of
clothes moths and woodworms
(2019)
In museums and historic houses clothes, moths (Tineola bisselliella, Tinea pellionella) and the furniture beetle (Anobium punctatum) are the most economically important pests on textiles or wooden artifacts, respectively. Their management is essential to protect cultural ethnological heritage and natural history collections for future generations.
Pest management strategies have changed over time. Today, intensive knowledge on pest biology and overall material science are key cornerstones in IPM concepts - also for the museum environment. The important first steps for sustainable pest management are risk assessment, early pest detection and identification of pathways of infestation. These steps are followed by physical and biological means of control, which have lately gained more importance than applying biocides.
Several potentially effective biological enemies of clothes moths and woodworm have been known for a long time, but their promotion for pest control in museums and historic houses is just beginning.
This short review summarizes current concepts of pest life cycle interruption by applying good quarantine and very specific biological measures. The lessons learned from recent faunistic surveys, life-history studies as well as behavioral observations of parasitoids and predators of clothes moths and woodworm may supplement the pest management tool box. The need for further research in this field is addressed.
The compatible solute ectoine is a versatile protectant synthesized by many prokaryotes. It is used as an osmolyte helping microorganisms to maintain an osmotic equilibrium. In addition, ectoine acts as a stabilizer and protects proteins, membranes and whole cells against detrimental effects such as freezing and thawing, drying and high temperatures. Its protective effect is explained by the preferential exclusion model, which postulates that ectoine does not directly interact with biomolecules but is excluded from their surface. Interestingly, details on the interaction of ectoine with DNA are still unknown. Therefore, we studied the influence of ectoine on DNA and the mechanisms by which ectoine protects DNA against ionizing radiation. To emulate biological conditions, we used a sample holder comprising a silicon chip with a Si3N4 membrane, which allows for electron irradiation of DNA in aqueous solution. Analysis by atomic force microscopy revealed that without ectoine, DNA was damaged by irradiation with a dose of 1,7 +/-0,3 Gy. With ectoine, DNA remained undamaged, even after irradiation with 15 Gy. Simulations with dsDNA and ectoine in water revealed a preferential binding of the zwitterionic ectoine to the negatively charged DNA. According to the simulations, binding of ectoine will destabilize dsDNA. Destabilizing is probably caused by the transition of B-DNA to A-DNA and will reduce the DNA melting temperature, which was experimentally proven. The preferential binding provides a stable ectoine shell around DNA, which allows ectoine to reduce OH-radicals and electrons near the DNA and thereby mitigating the damaging effect of ionizing radiation.
Hundreds of papyrus rolls, carbonized during the 79CE eruption of Mount Vesuvius, were discovered in 1754 at Herculaneum. Sophisticated mechanical methods for unrolling the best-preserved scrolls have been applied, with varying success. However, such processes have been abandoned, to prevent risk from irremediable damage or loss and to preserve the integrity of the extremely fragile rolls. Following the development of X-ray based non-invasive techniques, attempts to virtually unroll the scrolls were made. The most common ink in Antiquity was carbon-based, and the main element of carbonized papyrus is carbon, making these investigations difficult. However, some attempts with synchrotron X-ray phase-contrast tomography (XPCT) were successful. Recently, the identification of antique inks containing metals raised hope that if some of the inks contain metal the rolls can be virtually unrolled using conventional CT- technique. We are presenting here the first results of a preliminary analysis, which aimed at identifying scrolls whose ink contains metals.
Z02 is one of the three technically supporting projects at the Centre for the Study of Manuscript Cultures (CSMC). In collaboration with the other two service projects, Z01 and Z03, it aims at bridging the gap between humanities and natural sciences and technology. To that purpose, we set up a laboratory with a range of high-end instruments, most of them mobile, allowing thorough non-destructive analysis of manuscripts. In addition to working on constantly improving the laboratory and the methods of analysis, a substantial part of our activities is dedicated to service, by supporting different research projects conducted at the centre. In this talk, we will present our equipment and the possibilities offered by the different techniques available regarding the different kinds of missions: typology and classification of inks, provenance studies, recovery of faded inscriptions and palimpsests, reconstruction of the history of manuscripts, authentication and dating. We will give a brief overview of our past and ongoing activities in the frame of the second phase of the CSMC. Finally, a selection of three projects will be presented in greater detail to highlight the possibilities of our laboratory and the diversity of missions which can be carried out.
Ausgehend von der aktuellen Situation in Deutschland werden die Themen Baustoffaufbereitung, Ressourceneffizienz vorgestellt und Möglichkeiten zur Verbesserung der Baustoffqualität von Baurestmassen vorgestellt. Zielkonflikte und Beispiele dazu aus dem Baubereich (z.B. Mantelverordnung) werden benannt.
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in oil and gas facilities. SRM act upon the metal by the re-activeness of hydrogen sulfide (HS-), and by withdrawal of the available electrons in electrical contact with the metal (EMIC). Methanogenic archaea (MA) can also cause MIC (Mi-MIC). Several MAs were identified to be corrosive by using elemental iron as the sole electron donor for methanogenesis, including Methanobacterium-affliated IM1 and Methanococcus maripaludis Mic1c10. Currently, low corrosion rates were reported for MA, possibly due to the formation of siderite (4Fe + 5HCO3- + 5H+ ® 4FeCO3 + CH4 + 3H2O). Since MA do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of MA, we studied the EMIC methanogenic strains (IM1 and Mic1c10) individually or part of a syntrophic co-culture with SRM. Corrosion studies were conducted using an in-house developed flow-through system to simulate fluctuating environmental conditions. Results indicate that the rates of iron corrosion by MA (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr) and the co-culture (0.1 mm/yr). Scanning electron microscopy (SEM) images of the metal incubated with MA showed severe pitting corrosion. Genomic analysis of the EMIC MA was conducted to provide an insight on the possible cellular mechanisms that could be involved. Furthermore, low concentrations of MA-targeting biocides will be applied to EMIC MA in static and flow conditions to gain insights for possible mitigation strategies. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.
Since the recycling of tantalum bearing post-consumer waste is practically not existent, metallurgical residues are the most important feed for the tantalum recycling. Most tin ores naturally contain significant quantities of refractory metals. During the smelting process in primary tin production these elements are enriched in the slag phase. This slag is a highly valuable raw material for tantalum production due to its considerable concentration of tantalum and its functioning as an additional slag former in further pyrometallurgical treatment.
In this paper the first process stage of an existing pyrometallurgical process for tantalum recovery, mainly from low grade pyrometallurgical residues, is discussed. Smelting trials were carried out in a pilot-scale electric arc furnace to analyse the effect of feeding on the activity of carbon as a reducing agent. Therefore, blowing petroleum coke through an iron lance and the manual adding of coke into the melting bath were tested. During the pyrometallurgical treatment elements with a high affinity to carbon were reduced to their carbide form and enriched in the molten iron-based metal phase. The objective of the process was to reduce the oxidic tantalum completely and to enrich it into the metal phase. Furthermore, the transfer of unwanted elements such as titanium into the metal phase was aimed to be avoided.
Spoon test specimens were taken from the liquid mineral melt to follow the evolution of the reduction process. The cooled down solidified melting bath was investigated by using the XRD and EDX method to characterise the slag system and to identify relevant mineral phases.
An existing pyrometallurgical process for tantalum and niobium recovery, mainly from low grade pyrometallurgical residues, was investigated. Series of melting experiments were carried out in a pilot-scale electric arc furnace to study how the amount, the grain size and the way of feeding affect the activity of carbon as a reducing agent. During the pyrometallurgical treatment refractory metals such as tantalum and niobium are reduced to their carbide form and enriched in the molten iron-based metal phase. The cooled down slag and metal phase were analysed to investigate thermodynamic and kinetic conditions of the carbide formation. FACT Sage simulations were also used to investigate the material system in state of thermodynamic equilibrium. Results show that mass transfer and kinetics may play an important role if compared to equilibrium analyses using FACT Sage.
The use of secondary building materials can meet the requirements of sustainability in several ways: the extended time availability of primary raw materials and, thereby, the protection of natural ressources as well as the conservation of landfill sites. Regarding the predicted decrease of gypsum supply in Germany, particularly the recycling of gypsum (calcium sulfate) is of growing importance. Currently, the gypsum demand is fulfilled (at least 60%) by gypsum as side product from coal-fired power plants (FGD Gypsum). Germany’s natural gypsum deposits fulfil the remaining gypsum demand. Due to national climate protection goals the gypsum supply from coal power plants will decrease significantly in the future.
In addition, the content of sulfates in other secondary building materials, in particular in recycled concrete aggregates, should be minimized for quality reasons. Separated gypsum can be used in gypsum production if the high quality requirements for recycled gypsum are met. Accordingly, there have been significant advancements in the processing of gypsum residues in the last years. Since almost all processing steps in the recycling process are associated with environmental impacts, an evironmental evaluation of the use of recycled gypsum as a substitute in gypsum production has to be carefully conducted.
The presentation focusses on the techniques for generating recycled gypsum from gypsum plaster boards, the related quality requirements and a comprehensive environmental evaluation of the complete process.
The lecture traces the origins of paper, the manufacture and the spread from China to the Middle East and Europe.
Though technological progress considerably affected each step of the manufacture of paper, the essence of the invention remains unchanged until today. The process of manufacturing handmade paper can be divided into a number of steps:
- choosing the raw material (e.g. cellulose from wood, cotton, rags)
- beating and grinding the fibres into small pieces
- producing a liquid pulp of the desired texture
- treating the pulp with various additives
- filling the pulp suspension into a paper mould
- draining the water
- pressing and drying to get the actual sheet
- various post-production treatments
We will see how the manufacturing process is reflected in the properties of the paper and its degradation. A special attention will be paid to the instrumental analysis for identification of the paper types. Also watermark play an important role in the studies of the manuscripts. A short overview will be offered at the ends of the lecture.
Inks and pigments
(2019)
The writing materials used in various cultures and epochs can be divided into two groups. The first comprises materials that write themselves, producing script by rubbing their own material off onto the writing surface. It includes charcoal, graphite, chalk, raddle, and metal styluses. Depending on the material and consistency, these are cut or pressed to make styluses and then used for writing.
The second group comprises all coloring liquids that are applied to the writing surface with a quill, pen, or printing block. It includes inks made from dye solutions (for example, tannin inks) and those made from pigment dispersions (for example, sepia, soot, and bister inks). The latter are sometimes also rubbed as pastes into letters incised into the writing surface, where they increase visual contrast.
Due to the variety of recipes and the natural origin of raw materials, there is a wide range of different components and impurities in writing materials.
Soluble inks (Tinten)
Soluble inks are based mainly on dyes forming a water solution. Colored inks were manufactured with different plant or insect dyes (e.g. Brazil wood, kermes). To stabilize the volatile material, the dyes were mixed with a mordant (e.g., alum).
Brown plant inks – best-known as blackthorn or Theophilus’ inks – are usually produced from the blackthorn bark and wine. In the early European Middle Ages, inks of this kind were widely used in the production of manuscripts in monasteries. Usually, they are light brown, so sometimes small amounts of iron sulfate were added, which led to what was called an “imperfect” iron gall ink. The difference between “classic” iron gall ink and such imperfect ink is therefore not clear: the distinction is not possible, especially with the naked eye.
Dispersion inks (Tuschen)
According to its generic recipe, one of the oldest black writing materials is produced by mixing soot with a binder dissolved in a small amount of water. Thus, along with soot, binders such as gum arabic (ancient Egypt) or animal glue (China) are among the main components of soot inks. From Pliny’s detailed account of the manufacture of various soot-based inks, we learn that, despite its seeming simplicity, producing pure soot of high quality was not an easy task in Antiquity. Therefore, we expect to find various detectable additives that might be indicative of the time and place of production. One such carbon ink requires the addition of copper sulfate . The experimental discovery of this ink in 1990 led to a misleading expression “metal ink” that is sometimes found in the literature.
Colored dispersion inks based on pigments such as orpiment, cinnabar, or azurite have been known since Antiquity. Natural or artificially produced minerals are finely ground and dispersed in a binding medium. As in soot inks, water-soluble binders such as gum arabic or egg white were used.
Iron gall ink (Eisengallustinten)
Iron gall inks are a borderline case between these two groups. They are produced from four basic ingredients: galls, vitriol as the main source of iron, gum arabic as a binding media, and an aqueous medium such as wine, beer, or vinegar. By mixing gallic acid with iron sulfate, a water-soluble ferrous gallate complex is formed; this product belongs to the type “soluble inks”. Due to its solubility, the ink penetrates the writing support’s surface, making it difficult to erase. Exposure to oxygen leads to the formation of insoluble black ferric gallate pigment, i.e., “dispersion ink”.
Natural vitriol consists of a varying mixture of metal sulfates. Since for ink making it was obtained from different mines and by various techniques, inks contain many other metals, like copper, aluminum, zinc, and manganese, in addition to the iron sulfate. These metals do not contribute to color formation in the ink solution, but possibly change the chemical properties of the inks.
Parchment
(2019)
This lecture will present history of parchment based on written sources and chemical examination of antique, medieval and modern parchment.
Our studies of the Dead Sea Scrolls writing surfaces show that they can be divided roughly into three groups: leather, parchments of a light tint, and those of various shades of brown. The latter ones are invariably tanned, whereas the middle group is characterized by the presence of various inorganic salts. Some of the pale parchments, among them the Temple Scroll (11Q19), are remarkably similar to medieval European parchment. Therefore we have formulated the working theory that in the Judaea of the Hellenistic period two different parchment-making traditions existed side by side: an ‘eastern’ one (represented by the tanned parchments of Qumran, closely resembling Aramaic documents from the fifth century BC, and a ‘western’ one (represented by the untanned/lightly tanned ones similar to early Christian Greek parchments).
This division has found support during our studies of the Geniza fragments, in which Babylonian and Palestinian traditions seem to follow the “eastern” and “western” technologies, respectively.
Natural sciences play auxiliary role in the studies of manuscripts. The success of their contribution depends strongly on the formulation of the question and the choice of the methods to obtain the requested answer. Therefore, one should try to go beyond the understanding of the basic principles of the scientific analysis.
We will start with a glance at the basic principles of the techniques used in the material science for determination of the elemental composition (X-ray emission) and molecular composition (FTIR & Raman). We will move then to the bench and mobile equipment commonly used in the field of cultural heritage. At the end we will choose a question to be answered and design an ideal experiment that will be modified according to the limitations dictated by on-site conditions.
In the ateliers in the afternoon we will
a) compare two XRF devices that differ in their spatial resolution;
b) use a high resolution microscope (Keyence) to obtain a close look at writing surfaces and materials;
c) we will learn to determine the type of the inks with the help of another microscope (DinoLite AD413T-12V), a usb microscope with visible, UV and NIR illumination;
d) we will learn to use FTIR-ATR device for determination of the type of the writing surface;
e) We will use mobile Raman device for identification of pigments.
The evolution and socio-geographic distribution of writing inks from Late Antiquity to the Middle Ages are one of the foci of our investigative work at the Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin and the Centre for the Study of Manuscript Cultures, Hamburg University.
This presentation will examine the inks used by Jews in the in different geographical zones try to correlate the results of the material analysis with written records and existing traditions. We will compare the inks proposed by Maimonides, who lived in 12th-century Egypt, with the considerations of Rashi, who lived in 11th-century northern France, and see that they both advocated use of the inks commonly known and produced in their respective regions. It is Maimonides who proposes to add tannins to the soot inks, but rejects the metallic salt, both of which were practices that were well attested in contemporary Arabic recipes for making ink. In contrast, Rashi was favourable to employing the plant inks in use in contemporary Northern Europe.