Galvanic removal of metallic wrought iron from marine encrustations

Historic shipwrecks frequently contain a large proportion of wrought-iron tools, fasteners, and other types of artefacts. Encrustations readily form around such objects in many marine environments. Depending on many factors, the iron objects inside these encrustations may be well preserved, completely disintegrated, or poorly preserved but still present. The latter type of encrustation is every conservator's nightmare because removing the encrustation yields merely a poorly preserved artefact still in need of extensive additional conservation. Neatly separating the artefact from its encrustation in order to obtain a natural mould for casting is generally impossible. Having encountered this problem many times, the authors began to experiment with the extraction of metallic iron from poorly preserved encrusted artefacts using galvanic dissolution. Data on rates of dissolution were gathered for three experimental configurations. The results of a test conducted on an encrusted artefact were promising, but inconclusive.     

‘Guard the Good Deposit’: Technology,Provenance and Dating of Bipyramidal Iron Semi‐Products of the Durrenentzen Deposit (Haut‐Rhin,France)

In the early days of iron metallurgy in Western Europe, the most widespread type of ‘trade iron’ (semi‐product) was bipyramidal in shape. Although they are frequently found, little is known about how they were manufactured and circulated, or even about their age. An interdisciplinary approach was applied to the Durrenentzen deposit (Haut‐Rhin, France), the third‐largest in Europe in terms of artefact quantities, in an attempt to reconstruct the technological, social and economic context that caused them to be abandoned. A morphometric study of the 51 iron bars revealed a high degree of homogeneity, despite variations in detail. Four objects were selected for archaeometric studies. Metallographic analyses show internal differences (quality of the material, nature of the alloys and manufacturing techniques). Chemical analyses also showed different provenances. Finally, radiocarbon analyses of the carbon in steel (iron/carbon alloy) linked this deposit to the early Iron Age. This study provided the first benchmark for more general research, significantly changing perceptions of the economics of iron at the beginning of the Iron Age.     

试论陶器生活遗存所见西汉铁器手工业作坊的性质——以邰城铸铁作坊为案例

汉代铁器手工业的组织形式,一直以来讨论较多,却未有定论。本文提出,手工业作坊出土的陶容器的组合,有助于讨论作坊工匠的居住与组织形式,提供解决上述问题的线索。本文以陕西邰城铸铁作坊为案例,首先利用类型学建立分期框架,探讨作坊可能的运营持续时间。经统计分析,本文发现邰城作坊中炊煮陶容器的比例甚少。这一现象在西汉时期其他县级手工业作坊中相对普遍,但与战国时期作坊工匠居住于作坊范围内的情况不同,进而提出这一现象可能与工匠的居住和工作模式密切相关。本文指出,作坊出土的陶容器组合情况表明工匠可能不在作坊区内长期生活;铸铁作坊中工匠的身份可能也为雇佣工人,家庭式手工业作坊生产者的可能性不高。     

Methodological problems in the analysis of fossil non-artifactual wood assemblages from archaeological sites

The analysis of fossil wood fragments is often undertaken in relation to the archaeological excavation of a site. However, such analysis does not yet appear to have the strong methodological foundation that the investigation of many other classes of palaeoenvironmental evidence (e.g. seeds and pollen) have. Consequently, it is difficult to evaluate the value of fossil wood analysis at an archaeological site. Using data regarding non-artifactual wood assemblages at one site in southern Scotland, the relative merits of possible analysis are described and discussed. The results from such analyses tend to fall into two broad groups: (I) those of relatively high reliability, and (2) those of relatively low reliability. The results in the former group are often based on moderately secure methodology and tend to provide relatively non-interpretative information (e.g. species lists). On the other hand, those in the latter group are more often based on insecure interpretive methodology and provide relatively more stimulating information, such as evidence for prehistoric woodland management. There are many reasons for this situation, and these are discussed. In conclusion, it is argued that to increase the reliability of results in the second group (in particular), a full understanding of the taphonomy of non-artifactual fossil wood assemblages is needed, and that once this is available attention can then be paid, as elsewhere in environmental archaeology, to the problems of providing statistically valid samples for analysis.     

Analysis of the Effect of Provisional Ties on the Construction and Current Deformation of Mallorca Cathedral

This article presents the analysis of the structure of Mallorca Cathedral taking into account the influence on the structural behavior of auxiliary iron ties used during the construction process. Recent studies (Roca et al. 2012, 2013) presented some hypotheses about the construction process of the cathedral. This article complements the previous results by considering the use of auxiliary ties as temporary stabilizing device during the construction. Evidence of the use of ties during the construction has been recognized after a comprehensive survey. The study of the role of such ties and the effect of their later removal are studied by a FE analysis carried out on a representative bay of the structure. The study includes a time-dependent FE analysis after the removal of the ties to assess the long-term structural behavior. The results of the numerical analysis are compared with the deformation trends identified by means of a recent monitoring campaign.     

Churchill's ‘Iron Curtain’ Speech in Context: The Attempt to Achieve a ‘Good Understanding on All Points’ with Stalin's Soviet Union

More than 70 years ago, on 5 March 1946, former British Prime Minister Winston Churchill delivered his ‘iron curtain’ speech at Westminster College in Fulton. The speech immediately attracted worldwide attention and proved to be highly controversial. Most contemporaries in East and West and the vast majority of subsequent historians interpreted the speech as Churchill's call for western resistance to Stalin's expansionist policies and the continuation of the wartime ‘special relationship’ between Washington and London. This article argues, however, that Churchill's speech has been misunderstood. When set in the context of Churchill's other pronouncements on world affairs during his time as leader of the opposition between 1945 and 1951 and in view of his vigorously pursued ‘Big Three’ ‘summit diplomacy’ with Moscow and Washington after he returned as Prime Minister in 1951, the ‘iron curtain’ speech must be seen in a different light. It becomes clear that this famous speech was not Churchill's sabre-rattling call for commencing or energizing the East--West conflict with the Soviet Union. Quite to the contrary, his speech was meant to prevent the escalation of this conflict and avoid the dangerous clash between the world's greatest powers that soon became known as the Cold War.     

铁器文物保护中锈层化学稳定转化的研究

出土铁器文物在脱盐清洗后,运用化学稳定转化处理的方法将表面不稳定的铁锈转化成稳定、致密的锈层,然后进行钝化封闭,提高耐蚀性,最后进行防锈封护和表面消光处理。通过各种腐蚀性能测试,证明耐腐蚀性能有显著提高,综合处理的结果达到了文物铁器的保护要求。     

五女山城高句丽铁器金相学初步探讨

辽宁省本溪市桓仁县五女山城是高句丽第一代王朱蒙建都的纥升古城(公元前37年-公元3年)。在这一时期这一地域铁器的质地、加工工艺、手工业发展水平是冶金史学和考古学共同关注的问题,为深入了解高句丽民族铁器的应用及加工状况,本工作采集了出土于五女山城,多数集中放置在V区T504探方出土的一件铁釜内的铁器,进行金相学研究。为此采用金相显微镜、扫描电镜-X射线能谱仪作为检测和分析手段。检测结果表明,这些铁器的材质包括生铁铸造器物,局部灰口铸铁、低碳钢、熟铁,兵器和工具采用含杂质少的铸铁脱碳钢材料,铁钉采用含杂质多的炒钢材料,半成品铁块体现了生铁与熟铁相熔折叠锻打的工艺特征,与文献记载的"灌钢"方法之一的"灌"、"辟"相对应,而另一件环形铁器,内缘表面可观察到若干高碳薄层,与中心区域含碳量相差悬殊,并且观察到有石墨存在,显然也与熔融生铁的表面处理相关。这两件样品表明,至少在五世纪初,该地工匠已经在应用施加熔融生铁于熟铁的工艺。     

Dynamic One-Sided Out-Of-Plane Behavior of Unreinforced-Masonry Wall Restrained by Elasto-Plastic Tie-Rods

Past earthquakes have shown the high vulnerability of existing masonry buildings, particularly to out-of-plane local collapse mechanisms. Such mechanisms can be prevented if façades are restrained by tie rods improving the connections to perpendiculars walls. Whereas in the past only static models have been proposed, herein the nonlinear equation of motion of a monolithic wall restrained by a tie rod is presented. The façade, resting on a foundation and adjacent to transverse walls, rotates only around one base pivot and has one degree of freedom. Its thickness is explicitly accounted for and the tie rod is modeled as a linear elastic—perfectly plastic spring, with limited displacement capacity. The model is used to investigate the response to variations of wall geometry (height/thickness ratio, thickness), tie rod features (vertical position, length, prestress level), and material characteristics (elastic modulus, ultimate elongation, yield strength) typical of historical iron. The most relevant parameter is the steel strength, whereas other characteristics play minor roles allowing to recommend reduced values for pre-tensioning forces. The force-based procedure customary in Italy for tie design is reasonably safe and involves protection also against collapse, although probably not enough as desirable.