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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 investigated the inks of a selection of partially unrolled fragments stored at the Biblioteca Nazionale di Napoli with X-ray fluorescence in order to select the best candidates for tomography. Despite the many difficulties (analysis of several layers sticking together, letters barely visible, difficulty to separate contribution from the ink and from the papyrus, inhomogeneity of the support, fragility of the fragments…), encouraging results were found, with a number of inks from Greek fragments found to contain additions to the soot (Fe, Pb, Cu P).
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.
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 investigated the inks of a selection of partially unrolled fragments stored at the Biblioteca Nazionale di Napoli with X-ray fluorescence in order to select the best candidates for tomography. Despite the many difficulties (analysis of several layers sticking together, letters barely visible, difficulty to separate contribution from the ink and from the papyrus, inhomogeneity of the support, fragility of the fragments…), encouraging results were found, with a number of inks from Greek fragments found to contain additions to the soot (Fe, Pb, Cu P).
Recent research has suggested that some of the inks used in Herculaneum papyri do not consist of pure carbon. Starting from this finding, in June 2018 a preliminary campaign of analysis by means of X-Ray fluorescence (XRF) of external portions removed mechanically from their original rolls in the eighteenth century (the so-called scorze) took place at the Biblioteca Nazionale at Naples. Also in this case, the aim of the survey was to investigate the ink composition in order to detect possible traces of metal. This article sums up the results of this survey.
Nowadays, people spend most of their time indoors. Thus, a good indoor air quality is important. Emissions of volatile organic compounds (VOCs) from furniture and building materials can cause health complaints1. Quantitative VOC-emission testing is carried out under standardized conditions in emission test chambers. In the presented project an emission reference material (ERM) is developed that emits a defined mixture of VOCs which is required for quality assurance and -control (QA/QC) measures. Porous materials (e.g zeolites, activated carbons, MOFs or aerogels) are used as reservoir materials and impregnated with VOC. The porous materials are selected, among others, by their pore size, pore size distribution, polarity and availability. Due to their regular pore structure zeolites are tested at first. For a prediction of the emission profile, the ERM is supposed to exhibit a constant emission rate over time. The aim is a stability of ≤ 10 % change in the emission rate over a minimum of 14 days.
Method
For impregnation, the material is placed into an autoclave inside a rotatable basket. The VOC is added and the autoclave is closed. Afterwards, CO2 is inserted. The closed system is then heated to the supercritical point of CO2 (31 °C, 73.75 bar). In this state, the CO2 acts as solvent for the VOC. By rotating the basket, the distribution of the VOC is ensured. After a few minutes, the pressure is decreased slowly and the CO2 is released. For the determination of the emission profile, the impregnated sample is placed into an emission test chamber. These chambers can be operated either with dry or humid air (50 ± 5 % rel. humidity). Every second to third day, air samples are taken and analyzed by gas chromatography. For an ideal impregnation, several different pressures and temperatures as well as impregnation times are tested.
Results
Two zeolite materials tested in dry air conditions reach emission profiles with a decrease of less than 10 % over 14 days (heptane and toluene, respectively). Further it was discovered that smaller pellets of the same zeolite show better results than bigger particles. When the pore size of a zeolite is too small, e.g. 0.3 nm, the VOC cannot be absorbed sufficiently. The main disadvantage of zeolites is their hygroscopicity because it has a large impact on the release of VOC when they are used in emission test chambers under standardized test conditions (23 °C, 50 % rel. humidity). Activated carbons have emission profiles with a larger change over 14 days. However, the high hydrophobicity allows measurements in humid air conditions which was not possible with the before mentioned hygroscopic zeolites. It is possible to impregnate powdered materials as well, and thus powdered non-hygroscopic (n.h.) zeolites were impregnated. Their emission profiles are comparable to those of the activated carbons. The use of methylated hygroscopic zeolites with a decrease in hygroscopicity did not yield successful emission measurements. The change over 14 days is calculated only for the stable phase (~250–300 h).
The desired stability of ≤ 10 % change of the emission rate over 14 days could already be reached under dry testing conditions. Further investigations under humid conditions show that zeolites with high Si/Al-ratios are non-hygroscopic and comparable to activated carbons (20–30 % change). The next step is to reduce the change in the emission rate of these materials to the aimed ≤ 10 % over 14 days.
An approach to achieve 'zero leakage' is discussed with respect to experience in Germany, where strict regulations for landfill lining and capping Systems have been developed and issued because of large environmental Problems related to landfills that accumulated in the 1970s and 1980s. Using a thick, high-quality high-density Polyethylene (HDPE) geomembrane (GM) that is installed free of residual waves and wrinkles in intimate contact with a compacted clay liner or geosynthetic clay liner of very low permeability, by a qualified, experienced, well-equipped and properly third-party-controlled installer, and which is protected by heavy protection layers designed with respect to the long-term performance of the GM may result in a liner or capping system of practically no leakage. This is demonstrated by analysing results of measurements obtained from permanently installed leak-detection Systems in combination with HDPE GMs. The survey was based on 32 German landfills with 1.276.500 m² of installed GMs.