A preliminary study on using enzymes in cleaning archaeological wood

The main goal of this study was to study and evaluate the effect of hydrolyzing enzymes on the anatomical structure and chemical composition of archaeological wood samples. Pine and beech wood samples, which were taken from anonymous mashrabia, have been cleaned with three types of enzymes then a scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) study were undertaken, to see if any significant structural or chemical differences could be detected between “untreated” and “treated” wood. No dramatic changes in functional groups on the wood surface, as monitored by infrared spectroscopy, occurred in the samples before and after enzymatic cleaning. SEM data, however, show that protease and lipase enzymes may give good results in cleaning wood surface, but the enzyme residues remaining on the cell walls of archaeological wood are another point to consider.     

Physical and mechanical properties of waterlogged wood treated with hydrolyzed feather keratin

The physical and mechanical properties of waterlogged wood treated using avian feather were investigated. Avian feather is mainly composed of keratin protein and expectable materials for industrial utilization. The feather hydrolysate enhanced the mechanical properties of waterlogged wood and recovered the correlations between modulus of rupture (MOR) and modulus of elasticity (MOE) and anisotropy. The color of the wood treated with hydrolyzed feather solution exhibited natural wood texture. The feather hydrolysate had antimicrobial activity. However, the wood treated with hydrolyzed feather solution showed high hygroscopicity.     

Shape recovery of collapsed archaeological wood ware with active alkali-urea treatment

Most wooden remains from archaeological sites in waterlogged burial environments are found to be intact without shrinkage despite centuries of storage. However, waterlogged wooden remains are subject to shrinkage damage and some even lose up to 80% of their original volume when exposed to air. The shrinkage of archaeological waterlogged wood with the loss of a large part of the initial volume of the wooden remains has been considered irreversible. Here we show that “active alkali-urea”, serving as a re-swelling chemical agent, can almost fully restore the collapsed archaeological wood to its original shape. The restoration experiment showed that the main reason for the restoration of collapsed wood is that the collapsed cell cavity almost completely recovered its original shape during active alkali-urea treatment. We suggest that the shape of collapsed archaeological wood remains can be fully recovered, and that the collapsed archaeological wood can thereby recover its valuable cultural properties.     

四川绵阳出土的西汉饱水漆木器的前期保护工作

为保护四川绵阳出土的西汉饱水漆木器,使用脱水定型法对20件物进行了保护。选用甲醇脱水,十八烷醇加固定型的方法,继而作旧,封护。结果表明,经保护处理的物,其弦向平均收缩率为8％左右,径向平均收缩率为1％左右,说明保护处理是成功的。实验说明,甲醇一十八烷醇脱水定型法具有普遍的推广意义。     

Swift Creek at a human scale

ABSTRACT

The interpretive potential of Swift Creek pottery, widely produced throughout Georgia, eastern Alabama, and northern Florida during the Middle and Late Woodland periods between ca. cal AD 100 and 800, has been apparent for many years. Much research has been focused on identifying paddle designs from the impressions left on sherds. Less attention has been devoted to the carving of the wooden paddles and its social context. Drawing inferences from our work on Swift Creek pottery in southern Georgia and Florida, and drawing inspiration from the career of Mark Williams, we consider Swift Creek paddle production “at a human scale.” Extrapolating from the number of paddle designs identified in our sample, we argue that paddle manufacture was an infrequent occurrence, probably conducted by specialists and intended to commemorate major life events.     

考古木材降解评价的物理指标

为寻找一种能较为科学、方便地反映木材降解程度的指标,共收集不同地方出土的13种木材,8个树种,对这些树种的考古木材与新鲜木材的含水率、干缩性、基本密度、气干密度、综纤维素等指标进行对比分析。实验表明,基本密度和最大含水率(饱水含水率)基本上能够反映古木的降解程度,可以作为反映古木降解程度的物理评价指标。     

Study of interactions between polyethylene glycol and archaeological wood components by C high-resolution solid-state CP-MAS NMR

While use of polyethylene glycols, PEG, polymers for archaeological wood conservation has been well established, there is almost no study of such composite materials with carbon thirteen high-resolution solid-sate NMR. We demonstrate that NMR is an useful analytical tool to characterize rapidly samples of conserved wooden objects. By choosing an appropriate value of the contact time (from 3 to 5 ms) for which the PEG component gives only a small residual NMR signal in the CP-MAS experiment, it is possible to edit selectively the spectra of the wood components. It allows one to visualize the degradation extent of the archaeological wood even when the conservation processes have been already applied. Moreover, by studying the kinetics of CP-MAS experiments, the time constants, T_1ρH and T_CH values for PEG moiety were computed. From these data, it is shown that either in the crude commercial product or in incorporated in archaeological woods, two components are present and they are the signatures of crystalline (or ordered) and amorphous (or disordered) molecular domains. Moreover, it was shown in the archaeological woods that almost 30% of PEG was in close molecular interactions with lignins. This study is the first evidence that the PEG in conserved wood can interact at a molecular level with wood components. It also demonstrates that the PEG diffuses inside the residual cell walls of archaeological wood. This data are important for scientists in charge of process development for the conservation of wooden artifacts.     

The Yenikapı Byzantine‐Era Shipwrecks,Istanbul, Turkey: a preliminary report and inventory of the 27 wrecks studied by Istanbul University

Salvage excavations conducted in the Yenikap? quarter of the historic peninsula of Istanbul by the Istanbul Archaeological Museums 2004–2013 have brought to light the Theodosian Harbour on the Sea of Marmara. In addition to thousands of archaeological artefacts, a total of 37 shipwrecks dating from the 5th to the 11th centuries AD were uncovered, constituting the biggest collection of medieval ships uncovered at a single excavation site. The present article deals with 27 wrecks in the charge of the team from Istanbul University's Department of Conservation of Marine Archaeological Objects, consisting of 23 merchantmen and four galleys. The wrecks are presented with their general characteristics. The preliminary evidence from the Yenikap? wrecks regarding the development from shell‐based to skeleton‐based philosophy is discussed, and various building phases presented.     

泗水国出土泡桐材性研究

木质文物出土后环境发生了很大的变化,如不对其进行科学的保护处理就会发生快速的腐朽变化。在选择保护处理方法前对木材的材性进行科学的分析可以为保护方法的确定提供科学的依据。本工作从木材成分、含水率、干缩性、出土泡桐与新鲜泡桐干缩率比较、干燥过程中的电镜分析几个方面对泗水国汉墓出土的泡桐进行了材性研究。结果表明,泗阳汉墓出土的泡桐纤维素和半纤维素的含量比新鲜泡桐的含量下降很多,但木质素的相对含量却增加了,说明泗阳汉墓出土的泡桐在埋藏环境中可能更多地是受到褐腐菌的侵蚀。含水率的高低是反映木材腐蚀度一个重要指标,泗阳汉墓出土的泡桐平均含水率高达1211%,从弦向、径向、横切面的平均收缩率数值来看,出土的泗水国泡桐文物收缩变形很严重,从电子显微镜图片观察,细胞结构各向干缩特性与新鲜木材完全不同。由此可见,不能用常规木材的干缩特征和木材的变化规律来指导泗水国出土泡桐的研究和保护工作,在选择保护处理方法时要结合木材本身的现状选择适合的材料和工艺。     

甘肃糟朽木器安全状况评估技术研究

甘肃木器代表了我国汉代雕刻技艺的最高水平。糟朽是甘肃木器的典型特征,通常纤维素降解度高达50%;甘肃木器因材质固有的木材属性及缺陷性,对环境中的湿度、湿气和水分较为敏感,容易引发“湿胀干缩”效应,致使器物后期不易保存、保护。如何对糟朽木器安全状况进行科学评估,是当前基础研究领域亟待解决的课题。针对目前评估技术中存在的弊端、难题,本研究通过对评估方法、方式的深刻剖析,对木材材质特征及属性分析,对衡量及表征材质形态与结构变化相关物理参数的梳理;应用现代分析仪器及其成熟分析技术对采集试样进行了形貌观察和测试数据分析;研究表明:胎木含水率作为影响糟朽木器结构与形态稳定的决定因素,是安全评估的唯一衡量指标;胎木容重值、纤维结晶度与纤维降解度作为材质物理化学性能综合考量的表征参数,均客观地反映了材质质量或状况的实际变化情况,可作为量化评估参考指标;确定胎木含水率的安全变化范围为9.3%~14.3%,安全波动幅度为±5%。依据上述结果,制定了糟朽木器安全评估的相关界定标准:1)胎木含水率在安全范围、幅度内波动、变化时,表征参数物理量变化轻微,器物则处于安全区;2)胎木含水率超出安全范围变化时,且波动频率频繁,往往会持续引起容重值变小、纤维结晶度降低、纤维降解度增大,造成胎木的形态与结构发生严重改变,致使器物处于危险区;3)胎木丧失维持自身平衡效应的能力,致使表征参数物理量变化值极度异常,尤其当胎木素含量达到85%时,纤维素几乎完全降解,器物则已处于濒危区。最后,综合、梳理分析结果,设计、创建了科学、规范的糟朽木器安全评估技术构架,该技术采用定量与定性相结合的方式,特点是重数据、重证据,提升、强化了科技含量,方法简单、实用,易于掌握。