Degradation processes in colourless Roman glass: cases from the Bocholtz burial

A group of Roman glass objects from the Bocholtz burial in the SW of Limburg (The Netherlands) was found to have been subject to varying degrees of degradation. Many of the 25 colourless glass objects were fragmented to pieces <0.1 cm (“sugared”), whereas the three transparent blue-green glass objects were in near-pristine state. Analyses using SEM, XRF and EDS revealed that the fragmentation was the direct result of the intense leaching of Na₂O from the glass structure and its replacement with water. The resulting gel layers with low-Na₂O contents and large amounts of water are sensitive to cracking when they dry out. Thin-walled glass appears to be less sensitive to cracking from the resulting stress than thick-walled glass. Local differences in the moisture regime during burial also influence the severity of the glass degradation. Glass with low concentrations of CaO seems to be the most sensitive to this form of degradation. The typical blue-green Roman glass is less sensitive as it generally has considerably higher concentrations of CaO.     

青铜文物缓蚀剂效率及封护剂抗腐蚀能力的比较研究

为评价青铜文物缓蚀剂效率及封护剂抗腐蚀能力进行了两项电化学实验。一是利用直流腐蚀的极化电阻法对缓蚀效率评价,二是应用恒电位交流阻抗法对涂层的抗腐蚀效率评价。实验表明,复合缓蚀剂的缓蚀效率优于单一缓蚀剂如AMT、BTA,在模拟中性土壤介质的水溶液中各自缓蚀效率分别为88.7%、94.6%,两者组成复合缓蚀剂后其缓蚀效率高达98.8%,这是发挥其缓蚀剂各组分的协同效应的结果。应用恒电位交流阻抗实验,可以更好地理解附着有封护层时复杂的腐蚀过程。结果表明,石蜡涂层样品的Nyquist谱图出现扩散过程引起的阻抗特征;聚乙烯醇缩丁醛涂层、Paraloid B72涂层、空白样(缓蚀层BTA)三种样品Nyquist谱图均是由于涂层微孔引起的阻抗特征,在同一浓度下其抗腐蚀性能排序呈依次递减趋势。     

Ethnoarchaeological analysis of Arctic fish processing: chemical characterization of soils on Nelson Island,Alaska

Activity area analysis of archaeological soils using multi-element characterizations can illuminate how subsistence operations are organized and how subsistence behavior has changed over time, and is increasingly common at archaeological sites. However, in many regions it is impossible to examine the elemental signatures in known anthropogenic soil samples in order to compare them with unknown archaeological samples. This ethnoarchaeological study examines the chemical composition of the soils at known fish processing areas in the contemporary community of Tununak on Nelson Island, western Alaska. Using a quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS), the concentrations of the following elements in the soil extract were recorded in parts per million (ppm): aluminum (Al), barium (Ba), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), strontium (Sr), titanium (Ti), and zinc (Zn). Fish processing area features are elevated in various elements, including sodium, magnesium, phosphorus, potassium, and manganese, and Ba/Sr, Ba/Ca, and Sr/Ca are also useful in distinguishing between fish processing areas and offsite areas.     

An interdisciplinary approach to the understanding of past settlement and farming: two cases from SE Norway

An interdisciplinary approach involving analysis of plant macrofossils, pollen and soil micro morphology in combination with large-scale stripping of top soil, was applied in order to get a comprehensive understanding of pre-historic settlement, farming economy and land-use in Østfold, SE Norway. Investigations of 25 sites lead to two distinctive results: 1) A time-space perspective on usages of plants, and 2) Identification of agrarian activities in a relict field. Studies of these topics have hitherto been limited for this region. The results add fresh and essential knowledge to pre-historic times in Østfold and make a significant contribution to the understanding to these topics in neighbouring regions.     

Effects of site lithology on geochemical signatures of human occupation in archaeological house plans in the Netherlands

This study presents the application of multi-element soil analyses (X-ray fluorescence spectroscopy and inductively coupled plasma optical emission spectroscopy of 1 M HCl extracts) to grid samples from 3 archaeological house plans embedded in sandy clays, clays and sands to assess effects of site lithology on geochemical signatures of human occupation.     

'Enlivening' Development Concepts through Workshops: A case study of appropriate technology and soil conservation

In comparison with the teaching of most other geography topics, where fieldwork can be conducted relatively easily and seminars can be based on some pre-existing knowledge and first-hand experience of the issues, the range of resources and approaches available to tutors teaching the geography of development is necessarily more limited. Tutors often have to rely more heavily on 'top-down' teaching and more passive learning approaches, such as using videos, slides and lectures. While students may gain a theoretical understanding of development concepts, issues and problems, they may be left without a deeper 'experience' of such material. This paper describes a practical workshop designed to communicate to students the idea of 'appropriate technology'. The workshop enables students to actively 'experience' a development concept rather than simply understand it in theory. It tests comprehension and understanding, through the application of a concept to real examples, stimulates discussion and debate, and draws upon problem-solving and critical thinking skills.     

Reconstructing site organization in the eastern Aleutian Islands,Alaska using multi-element chemical analysis of soils

This study presents the results of multi-element analysis of weak-acid extractions of 953 soil samples collected by coring on and around pre-historic village sites on two islands, Sanak and Amaknak, in the eastern Aleutians. Concentrations of aluminum (Al), barium (Ba), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), strontium (Sr), titanium (Ti), and zinc (Zn) were determined using an inductively coupled plasma-mass spectrometer (ICP-MS). Resultant elemental signatures allow the identification of site features and organization in the absence of large-scale excavation. All the archeological sites showed similar and distinct chemical signatures regardless of the several thousand year date range of the sites or the length of time a site was occupied. However, intensity of occupation does appear to affect concentrations of elements. Site features such as houses, house berms, house floors and middens had distinct anthropogenic signatures and could be distinguished from one another. This approach may be used to identify sites that do not have distinct surface features and to target areas for excavation.     

Applying the H/V Method to Dense Cities. A Case Study of Valencia City

The aim of this study was to apply Nakamura's technique to Valencia city center, after some preliminary tests in Barcelona. Previous studies of Barcelona had measured periods in restrictive conditions and in various types of material ranging from very soft soil (with a predominant period of approximately 2 s) to rock (0.3 s), and under different measurement conditions. The Valencia city center measurements were taken by using the distance from buildings and car and pedestrian traffic to construct a measurement grid that was as regular as possible. We also estimated possible soil-structure interaction to detect potential vulnerability.     

A Simplified Calculation Method for Liquefaction-Induced Settlement of Shallow Foundation

This work was aimed at developing a practical and simple settlement estimation of shallow foundation on liquefiable deposits. The study conducted a centrifuge test, a series of comprehensive numerical analysis, back analysis, equation calibration, and verification with data from not only centrifuge test but also the literature. It finally proposed a quick calculation method based on Meyerhof’s settlement equation (1965). A two-dimensional numerical analysis, named ALID, (Analysis for Liquefaction-induced Deformation), was employed for obtaining settlement of shallow foundations on liquefiable soils with different relative densities under various seismic conditions. Its performance was first verified through a centrifuge test conducted in this study. Then, the developed method based on Meyerhof’s settlement equation was employed, and a new parameter, N_LR, was proposed to present the strength of liquefied soils by replacing N value in the original equation. The N_LR was obtained through back analysis of the numerical results and modified accordingly after comparison with the data from the literature. This paper, finally, demonstrated the practical use of the proposed method involving N_LR by predicting 199 sets of liquefaction-induced settlement of shallow foundation reported in the past, including a latest most liquefaction-induced settlement of a house in 0206 earthquake on February 6, 2016, in Taiwan.     

Practical surveying in schools

Analysis of detailed geomorphological mapping enables a sequence of glacial events to be established. An ice sheet whose source was to the west of the area of study is shown, by the suites of fluvioglacial landforms produced, to have down‐wasted in situ; meltwaters escaped beneath or through the ice, moving uphill across certain areas. Finally, a sub‐aerial drainage system was established and outwash terraces were spread down valley.