Waterlogged archaeological wood can be preserved for many years in the absence of air, as decomposition is substantially slowed down. After excavation, conservation is necessary to prevent damage of objects due to uncontrolled drying. In this study, the following conservation methods were tested to investigate their ability to stabilise the objects: alcohol-ether resin, melamine-formaldehyde (Kauramin 800), lactitol/trehalose, saccharose, polyethylene glycol (PEG 2000 with air-drying and PEG 2000 or 400 and 4000 with subsequent freeze-drying). In order to precisely understand the changes caused by conservation and drying, 40 samples each of pine wood and oak wood were documented using magnetic resonance imaging and X-ray micro-computed tomography before and after conservation. This imaging made it possible to quantitatively record changes in the wood structure, for example due to shrinkage, collapse and cracks, which could not be prevented by conservation. The alcohol-ether-resin method with solvent drying had the best stabilizing effect and no damage of the wood structure was visible. The two PEG treatments followed by freeze drying showed effective volume stabilisation. In both cases, however, the treatment led to cracks in the wood structure, which occurred less frequently when the cryoprotectant PEG 400 was used. In comparison, the other methods with air drying did not show consistently good results in stabilizing the volume or wood structure.

Archaeological wood can be preserved in waterlogged conditions. Due to their degradation in the ground, these archaeological remains are endangered after their discovery, since they decay irretrievably during drying. Conservation measures are used to preserve waterlogged archaeological objects, maintaining their shape and character as much as possible. However, different methods have been developed leading to varying results. This study compares their effectiveness in order to clarify their mode of action. The methods including alcohol-ether resin, lactitol/trehalose, melamine formaldehyde, polyethylene glycol impregnation prior to freeze–drying, saccharose and silicone oil were assessed by analysing mass changes and volume stability using structured-light 3D scanning. The state of the conserved wood samples including the spatial distribution of the conservation agent was examined using synchrotron micro-computed tomography. Raman spectroscopy was used to observe the agent´s spatial distribution within the cells. The findings demonstrated that melamine formaldehyde stabilises the degraded cell walls. The lumens are void, as in the case with alcohol-ether resin, while polyethylene glycol, silicone oil, saccharose and lactitol/trehalose also occupy the lumens. It is assumed that the drying method has an effect on the distribution of the solidifying agent. The knowledge gained affords insights into the mechanism of conservation methods, which in turn accounts for the varied outcomes. It also allows conclusions to be drawn about the condition and stability of conserved museum objects and serves as a starting point for the further development of conservation methods.

In the Neolithic pile-dwelling settlements of southwestern Germany, bark played a prominent role in the production of technical textiles. So far, the inner bark (phloem) of the lime tree (genus Tilia) could be detected most frequently. Microscopic examination of anatomical features can determine the taxon, requiring manipulation of samples and archaeological objects. In this study, micro-computed tomography (µCT) was reviewed as a method for determining the woody taxon and obtaining additional information from the inner bark. To this end, modern bark samples from different tree organs of lime were first analysed using both µCT and transmitted light microscopy. Both methods were able to detect all characteristic anatomical features in the phloem and identify the genus. With analysis based on µCT data, further anatomical information can be obtained. For example, the shape of the phloem rays in the bast strips can provide information on the position within the bark and on the original organ diameter. These results obtained on modern material were verified on four samples from archaeological objects. Based on µCT, all samples could be clearly identified as lime and in two cases conclusions could also be drawn about the raw material. This approach could lead to new results and interpretations in archaeological sciences.

Cultural heritage objects made of wood can be preserved under waterlogged conditions for many years, where decay is slowed down and the wood structure is more or less completely filled with water. Depending on the degree of degradation, finds may collapse and shrink when they are allowed to dry in an uncontrolled manner after excavation, leading to total loss of the object and its information. Conservation measures are taken to prevent damage of objects and dimensional stability is an important criterion. In this study, structured-light 3D scanning and micro-computed tomography were used to analyse the dimensional stability of wood after conservation, as well as its long-term stability. 83 samples from a reference collection established between 2008 and 2011 allowed this comparative study of the most common conservation methods at that time. The effects of conservation methods using alcohol-ether resin, melamine-formaldehyde (Kauramin 800 ® ), lactitol/trehalose, saccharose, and silicone oil on dimensional stability were investigated. In addition, different polyethylene glycol (PEG) treatments with subsequent freeze-drying were also investigated: one-stage with PEG 2000, two-stage with PEG 400 and PEG 4000 and three-stage with PEG 400, PEG 1500 and PEG 4000. The data received from analyses of both volume and surface gave detailed information about the success of each conservation method. Attempts were made to quantify the damage patterns, specifically shrinkage, collapse, and cracks. While PEG and freeze-drying, alcohol-ether-resin, as well as the Kauramin 800 ® method gave the best results, analysis also highlighted the failures of each method.

aus Bein mit der feineren Zinkenreihe nach links

AbstractHelikale Strukturmotive sind in der Natur omnipräsent, z. B. als DNA‐Doppelhelix oder Kollagen‐Tripelhelix. Bei letzterer ist die helikale Struktur durch Glycin bedingt, der kleinsten Aminosäure, dessen molekulare Konformation eng mit der von Essigsäure verwandt ist. In Calciumacetat‐Hemihydrat, entstanden aus der Reaktion von Essigsäure mit in der Natur allgegenwärtigem Kalk und Wasser, wurde jetzt eine kollagen‐artige Tripelhelix entdeckt. Dieses Calciumsalz wird als Ausblühung auf Molluskenschalen, Keramik oder Marmor beobachtet. In einem Modellexperiment wurde reines Calciumacetat‐Hemihydrat auf der Oberfläche eines Terrakotta‐Gefäßes auskristallisiert. Calciumacetat‐Hemihydrat kristallisiert in einer überraschend großen Elementarzelle mit einem Volumen von 11 794.5(3) Å3 bei Normalbedingungen. Acetat‐Ionen verbrücken benachbarte Calcium‐Kationen und bilden Spiralketten, die in einer Tripelhelix‐Struktur angeordnet sind.

The Front Cover shows historic glass earrings with brass mountings from the Hamburg Museum in the background. The metal parts exhibit severe corrosion, especially where they are in contact with glass. The partial dissolution of the historic glass by moisture leads to a surface film containing formates produced by a Canizzaro reaction of formaldehyde, emitted by, e.g., wooden furniture, with the alkaline components of the film. An excerpt of the crystal structure of a new corrosion phase, Zn4Cu3(Zn1–xCux)6(HCOO)8(OH)18·6(H2O) (“Zinc C”), is presented. More information can be found in the Full Paper by S. Bette et al. For more on the story behind the cover research, see the Cover Profile.

Mit rund 1300 Grabern aus dem Zeitraum vom spaten 5. bis zum spaten 7. Jahrhundert ist das Graberfeld von Lauchheim ‚Wasserfurche‘ (Ostalbkreis) bis heute der groste bekannte merowingerzeitliche Bestattungsplatz Suddeutschlands. In den Jahren 1986 bis 1996 wurde das fast vollstandig erhaltene Graberfeld grosflachig ausgegraben. Seit 2009 widmete sich ein multidisziplinares Forschungsprojekt der Dokumentation und Auswertung der Lauchheimer Graber und Grabbeigaben. Dabei kamen in grosem Masstab innovative Dokumentationsmethoden mit dem Ziel einer moglichst vollstandigen Datenerfassung zum Einsatz. Als Ergebnis dieses Projekts werden die Befunde und Funde aus Lauchheim in einem detaillierten Katalog mit umfangreichem Tafelteil vorgelegt und damit der weiteren wissenschaftlichen Auswertung zuganglich gemacht. Der vorliegende zweite von insgesamt vier Teilbanden des Katalogs umfasst die Graber 301–600. Als Datensupplement werden Abbildungen der Perlen aus den Grabern bereitgestellt. Die Abbildungen liegen als separate tif-Dateien sowie zusammengefasst in einer pdf-Datei vor. Die Dateinamen der einzelnen Bilddateien setzen sich aus der Grabnummer, der Objektnummer und einer Bildnummer zusammen.

Invited for the cover of this issue is Sebastian Bette from the Max Planck Institute for Solid State Research, Stuttgart, Germany. The cover image shows a picture and structure of a corrosion phase formed at the contact between historic glass and brass.

Les series d'essais effectuees jusqu'a present prouvent qu'il est tout a fait possible de mettre au jour un ensemble d'objets trouves sur un meme site, composes de plusieurs elements et enrobes dans un bloc de plâtre, de faire une documentation de ces objets et donc de proceder a une vaste reconstitution de leur milieu et ce, de maniere purement virtuelle. En effet, la tomographie 3D a rayons X permet de saisir avec precision, d'identifier et de proceder a une affectation typologique des objets qui ont ete enrobes dans un bloc de plâtre en les laissant dans leur position d'origine, sans alterer leur sequence stratigraphique. Cette methode permet egalement de visualiser les structures externes et internes de ces objets et donc de voir a partir de quels materiaux ils ont ete constitues et dans quel etat ils se trouvent et meme parfois de detecter leur degre d'usure.

Mit rund 1300 Grabern aus dem Zeitraum vom spaten 5. bis zum spaten 6. Jahrhundert ist das Graberfeld von Lauchheim ‚Wasserfurche‘ (Ostalbkreis) bis heute der groste bekannte merowingerzeitliche Bestattungsplatz Suddeutschlands. In den Jahren 1986 bis 1996 wurde das fast vollstandig erhaltene Graberfeld grosflachig ausgegraben. Seit 2009 widmete sich ein multidisziplinares Forschungsprojekt der Dokumentation und Auswertung der Lauchheimer Graber und Grabbeigaben. Dabei kamen in grosem Masstab innovative Dokumentationsmethoden mit dem Ziel einer moglichst vollstandigen Datenerfassung zum Einsatz. Als Ergebnis dieses Projekts werden die Befunde und Funde aus Lauchheim in einem detaillierten Katalog mit umfangreichem Tafelteil vorgelegt und damit der weiteren wissenschaftlichen Auswertung zuganglich gemacht. Der vorliegende erste von insgesamt vier Teilbanden des Katalogs umfasst die Graber 1–300. Als Datensupplement werden Abbildungen der Perlen aus den Grabern bereitgestellt. Die Abbildungen liegen als separate tif-Dateien sowie zusammengefasst in einer pdf-Datei vor. Die Dateinamen der einzelnen Bilddateien setzen sich aus der Grabnummer, der Objektnummer und einer Bildnummer zusammen.