Numerical Analyses of the Effectiveness of Soft Barriers into the Soil for the Mitigation of Seismic Risk

An approach to mitigate the seismic risk of existing structures by means of the creation of a continuous thin layer of grouted soil at a convenient depth is presented. A parametric numerical analysis is reported using different constitutive models with reference to two geometrical schemes. It is shown that if the grouted layer has a stiffness significantly lower than that of the surrounding soil, it may be effective in reducing the seismic demand. In the parametric analyses, the positive role of yielding is also observed, which indicates that the barrier is more effective with larger input amplitudes.     

Chemical durability of lead-bearing glazes in sulphuric acid solutions — Laboratory experiments performed on Zsolnay architectural ceramics from Budapest (Hungary)

This study aims to simulate the long-term deterioration of architectural glazes exposed to open air in a highly polluted urban environment. A laboratory experiment—a 14-day long accelerated weathering test—on glazed roof tiles has been performed to reveal the damaging influence of contacting acid solutions originating from dissolved gaseous pollutants, mainly SO₂. The studied tiles are made by the Hungarian Zsolnay factory and applied on two buildings in Budapest in the 19th and 20th century. The ceramics were covered mainly by lead glazes in the construction and lead-bearing alkali glazes in the renovation periods.

The solution of pH2 induced a greater dissolution, especially of alkali and alkaline earth metals (up to 2886 ppm), but less lead (up to 21 ppm) from the lead glazes of the construction periods. Newly formed lead sulphate (anglesite) on the corroded glaze parts precipitated on some lead-bearing alkali glazes, with moderate dissolution of alkali and alkaline earth metals (up to 396 ppm) accompanied by higher amount of lead (28–39 ppm). Based on the results, the main determining factor in the durability of glazes is mostly their chemical composition and less their preliminary degradation state.     

馆藏金属器物上浅蓝色铜锈蚀物的辨别与成因分析

不同于新出土青铜器上的锈蚀物,博物馆藏金属器物上经常可见浅蓝色铜的锈蚀物。为辨别和探析其成因,通过采用扫描电子显微镜-能谱仪(SEM-EDX)、X射线衍射仪(XRD)和激光拉曼光谱仪(Raman)进行元素成分和物相综合分析,发现其为铜的有机盐。这些有机盐包括简单(或碱式)的甲酸铜和乙酸铜,也包括复杂的含有钠离子和碳酸根的乙酸铜NaCu(CO₃)(CH₃CO₂)、含有钠离子和氧离子的水合甲酸铜Cu₄Na₄O(HCOO)₈(OH)₂·4H₂O。这种浅蓝色铜的有机盐形成根源主要有两种:储存或展览环境的不当;用于除锈的化学试剂的残留。要杜绝这类锈蚀物的形成需要确保储存和展览器物的环境低湿度且无有机酸释放材料的存在。对经过化学处理的器物应确保将化学试剂清理干净且无任何残留以绝后患。对复合材料器物的处理更应谨慎,因为对不同材质的处理和保存环境要求不一样,要个例对待。     

长江口咸淡水混合水域腐蚀性细菌的筛选及其对文物的腐蚀作用

近年来,针对文物在海水中的细菌性腐蚀研究主要集中于海域沉积,但关于咸淡水混合水域的腐蚀性细菌研究鲜有报道。河口及近海岸水域是水下文物较为丰富的区域,咸淡水交互作用影响水下文物的埋藏环境和文物遗存。本研究采集长江口北港拦门沙Ⅱ号沉船附近海底不同层次的海泥,通过非定向富集培养基培养,分离纯化得到18株菌,经16S rDNA鉴定出4种具有腐蚀性的细菌：哈夫尼希瓦氏菌(Shewanella hafniensis)、越南芽孢杆菌(Bacillus wiedmannii)、金橙微小杆菌(Exiguobacterium aquaticum)和微小杆菌(Exiguobacterium indicum)。将分离得到的细菌作用于瓷质、陶质和木质等常见文物材料,置于30℃摇床220 r/min转速下培养7 d,喷金干燥,扫描电镜下观察,均可见在材料表面上产生生物膜。生物膜与微生物腐蚀的发生密切相关,除了已报道具有腐蚀性的菌株外,还发现了2株先前并未报道但也在材料表面产生生物膜的菌类：萘醌对希瓦氏菌(Shewanella xiamenensis)和嗜水气单胞菌(Aeromonas hydrophila)。实验...     

良渚古城老虎岭水坝遗址考古剖面保护研究与工程实践

良渚古城老虎岭水坝遗址是我国迄今发现最早的大型水利工程系统中的一处典型遗存,对中国文明起源和世界文明史的研究具有重要意义。为清晰地展示老虎岭水坝土遗址上“草裹泥”筑坝工艺的痕迹,针对温热、潮湿、多雨环境土遗址保护的难题,在总结吸取国内土遗址保护经验教训的基础上,借助浙江大学的研究成果和敦煌研究院的工程经验,提出了一套避免使用化学材料加固,而以“黑屋+隔水+控湿”为主的小环境控制工程策略,包括:构建遮光大棚以避雨和抑制绿色生物生长;铺设防水毯以防止坝体渗水;设置电加热玻璃罩以保湿和封闭展示面;采用气相补水以调控空气湿度和土体含水率;采用植物精油等绿色环保技术防治微生物;同时做好遗址实时监测和管护等。这套综合保护措施是土遗址保护理念和工程实践的一次新的尝试。     

几种罕见的黄铜钱币锈蚀产物的识别与形成原因探析

我国从明中期开始使用黄铜钱币,一直到清末。过去,对古代铸币的科学研究主要集中于合金成分分析和铸造工艺两方面,对锈蚀产物和锈蚀机理的研究主要针对青铜铸币。黄铜的合金元素中较青铜多锌元素,其腐蚀产物与腐蚀行为较青铜有一定的差别,也较青铜更为复杂,然而现有的文献关于此方面的研究匮乏,特别是对于大气保存环境下黄铜钱币的锈蚀产物及锈蚀成因的研究基本空白。本研究通过多种分析手段包括X射线荧光分析仪(XRF)、扫描电镜能谱仪(SEM-EDS)和显微激光拉曼光谱仪(Raman)对国家博物馆馆藏一批传世明清各时期的黄铜钱币合金组成,不同颜色的锈蚀产物等开展科学分析。研究结果表明,嘉靖、隆庆和万历年的黄铜铸币,为Cu+Sn+Pb+Zn四元合金,平均含量Cu 66.4%,Sn 6.8%,Pb 10.4%,Zn 15.6%,并含有微量Fe,不含As。泰昌、天启和崇祯年间及清代各时期的黄铜铸币,主要为Cu+Pb+Zn三元合金,并含有微量Fe、As和Sn。这批黄铜锈蚀产物与常见的青铜锈蚀产物不同,最典型的是钱币表面蓝绿色和白色锈蚀物,经Raman和SEM-EDS分析并结合相关文献初步确认蓝绿色锈蚀物为一种含铜、钠...     

通古斯巴西古城遗址土体特性及PS加固试验

通古斯巴西古城遗址是新疆重要的土遗址之一,原为唐龟兹驻兵的安西都护府所在地。遗址中曾出土大批文物,对于研究西域的屯垦历史和古代城址布局等有重大意义。为了系统地研究了通古斯巴西古城遗址土的工程特性,在实地调查的基础上,通过室内试验对通古斯巴西古城遗址土的物理、力学、水理和化学性能进行测试。此外,还测定了不同PS浓度加固后遗址土重塑土块抵抗风蚀雨蚀能力的差异,进一步确定了PS的渗透加固措施对土质文物的防风化及雨蚀效果。结果表明,7%的PS溶液防风化抗雨蚀效果要更为显著。研究结果可为PS的施工应用提供依据。     

The behaviour of lead as a corrosion resistant medium undersea and in soils

Lead is a highly corrosion resistant metal in some environments and an attempt has been made to show its strength and weakness under long-term corrosion in land and marine conditions by means of examples taken from archaeological contexts. Some analyses and thicknesses are given of the corrosion films found on them. The importance of fine grain size and the role of certain impurities in obtaining this may be one reason why the older leads are often more resistant than modern leads.     

Soil mark studies near Winchester,Hampshire

The fate of artifacts incorporated into the ploughsoil as a result of plough damage is considered in terms of two soil mark sites near Winchester, Hampshire. Ploughsoil and subsoil analyses indicate that dispersal of soil material, as a result of ploughing, is limited at the present time and under mould board ploughing techniques. The origin of soil marks underlain only by bedrock is also considered and evidence indicates that such soil marks may appear as groundsurface expressions of ditches which have been removed by plough damage where dispersal of ploughsoil is minimal. Such soil marks may be only short lived if plough depth continues to increase.     

The decomposition of starch grains in soils: implications for archaeological residue analyses

Recent research involving starch grains recovered from archaeological contexts has highlighted the need for a review of the mechanisms and consequences of starch degradation specifically relevant to archaeology. This paper presents a review of the plant physiological and soil biochemical literature pertinent to the archaeological investigation of starch grains found as residues on artefacts and in archaeological sediments. Preservative and destructive factors affecting starch survival, including enzymes, clays, metals and soil properties, as well as differential degradation of starches of varying sizes and amylose content, were considered. The synthesis and character of chloroplast-formed ‘transitory’ starch grains, and the differentiation of these from ‘storage’ starches formed in tubers and seeds were also addressed. Findings of the review include the higher susceptibility of small starch grains to biotic degradation, and that protective mechanisms are provided to starch by both soil aggregates and artefact surfaces. These findings suggest that current reasoning which equates higher numbers of starch grains on an artefact than in associated sediments with the use of the artefact for processing starchy plants needs to be reconsidered. It is argued that an increased understanding of starch decomposition processes is necessary to accurately reconstruct both archaeological activities involving starchy plants and environmental change investigated through starch analysis.