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41.
The soil which has developed at any given location is considered to be the result of five interacting factors: parent material, time, climate, topography and biotic factors. This paper discusses the role of these factors in the development of Scottish soils, which fall into three broad categories: leached soils, gley soils and organic soils. The intention is to provide a context for the case studies that follow in later papers.  相似文献   
42.
Surfaces on ceramic artifacts that are paler than the main sherd body are commonly interpreted as slips that were intentionally applied by the potter during the manufacturing process. However, due to post-depositional alteration, sherds that were not originally coated with a slip may macroscopically appear with deceptively similar pale surfaces. This paper presents a comparison of two sherds, both with pale to white surfaces, one of which is a real slip and the other a surficial corrosion that occurred during the burial stage. Observations using optical and scanning electron microscopy, as well as electron-probe image- and microanalysis, clearly illustrate the features of the two surfaces, as well as demonstrating their causes and effects. The superimposed slip is clearly delimited from the sherd body by a denser and much finer-grained fabric, in which clay minerals predominate and porosity is reduced by about 20% compared to the body. In the other sample, surface corrosion, due to invading fluids, has led to leaching of calcareous constituents and results in a remarkable increase in porosity close to the rim (ca. 25%). Sometimes called the “espresso crema effect” (Tschegg et al., 2009b), the surface becomes considerably brighter than the core and can easily be confused with intentional slips. This, as a consequence can lead to significant misinterpretations, to erroneous sherd characterizations and classifications, as well as to incorrect assignments to specific ware groups.  相似文献   
43.
为探求符合文物保护要求的青铜器保护处理方法,对青铜病形成的过程和原因进行了模拟小孔腐蚀实验研究。对青铜模拟闭塞电池内的化学和电化学状态的变化,进行了不同Cl~-浓度和不同的pH值溶液条件下的电化学测试。实验结果证明,青铜闭塞孔穴腐蚀能导致蚀孔内Cl~-浓缩,pH值降低,腐蚀电流增大,局部腐蚀的加速,导致青铜病的形成。青铜病的闭塞孔穴腐蚀特征的研究,对进一步探求符合文物保护要求的青铜器保护处理方法具有较好的理论指导意义。  相似文献   
44.
The archaeological record of dry rockshelters in the Red River Valley of eastern Kentucky contains botanical remains of several weedy annual seed-bearing plants that point to the independent development of agriculture during the Late Archaic and Early Woodland Period. The objective of this study is to gather quantitative data through the chemical and physical analysis of soils collected within a valley transect to gain insights into landscape processes and soil fertility that may have played a role in the early development of plant domestication and the location of garden plots in relation to rock shelter sites in the upper Cumberland Plateau region of eastern Kentucky. Soils on upland benches formed in limestones have soil fertility values that are comparable to fertile floodplain soils. Upslope outcrops of calcareous bedrock are contributing basic cations to these bench soils. Additionally, in comparison to other landscape positions these upland soils have high levels of organic carbon, available P and greater C:N ratios. Soil morphology, radiocarbon dates, and archaeological evidence indicate that many of the numerous earthflows and debris flows within the region are Early to Middle Holocene in age. These slides were likely generated by Mid-Holocene climatic shifts in which the frequency and intensity of summer precipitation increased across the southeastern United States. These slope failures may have contributed to the development of plant domestication by creating forest canopy gaps and disturbed soils in which weedy plants thrived.  相似文献   
45.
A micromorphological study of the sediments from the cave of Pech-de-l'Azé II using the terminology of Brewer (1964) was undertaken in order to describe them, to compare the results and their palaeoclimatic interpretations (e.g., Laville, 1973) with those of classical sedimentological analyses and to evaluate the role of micromorphology in the analysis of cave and rock-shelter deposits.The soil skeleton is composed of quartz sand and silt resulting principally from the decay of bedrock with local reworking by solifluction and ruissellement. Lithorelicts consist of bedrock fragments of cryoclastic origin and detrital phosphate grains which can be identified as being large carnivore (bear or hyaena?) coprolites. The plasma is composed of mostly iron rich clay and although it was most abundant in reddish layers of previously recognized soils, no micromorphological evidence for clay illuvation was found. The latter might have been caused by post-depositional destruction by freeze and thaw which produced the generally well developed banded fabrics in many of the beds. Free grain argillans occur sporadically but are particularly well developed on phosphate grains. Secondary calcite, occurring either in dispersed zones or as void calcitans and neocalcitans occurs throughout but is more marked in the upper layers and bed 6.Micromorphologically based palaeoclimatic interpretations agreed on the whole with those obtained by classical sedimentology although several questions were raised which should make us more cautious in interpreting “classical” data: such as the origin of the clay, especially in “soil” horizons. The advantages of micromorphology in delineating sequence of events were indicated.  相似文献   
46.
杭州萧山老虎洞东周遗址出土两件青铜工具,工具出土时已碎裂为数段,锈蚀状态严重。针对两件青铜工具的研究,主要从微观领域来探讨青铜工具的工艺技术及腐蚀特点,并通过建立电化学反应模型,运用电极电位差的理论,来试析电极电位对金相组织腐蚀的影响。同时提出在青铜修复时,可利用电极电位的原理来补配修复材料,以达到文物保护的目的。  相似文献   
47.
ABSTRACT

Reinforced concrete structures came to Spain in the late-19th century, somewhat after the development of this new construction material elsewhere in Europe. Their introduction was pioneered in industrialized areas, especially Northern Spain, under systems first patented in other European countries. Local constructors built structures under patents with little or no explanations to account for calculation, design, and construction technique. Some of these buildings from the recent past are now listed buildings. This study centres on three construction projects under patented systems: Our Lady of “La Antigua”, Orduña (Monier system), “La Ceres” flour mill, Bilbao (Hennebique system), and Alhóndiga, Bilbao (Blanc system). Preliminary structural studies analyzed morphology, reinforcements, concrete strength and pathological processes in each structure. Their results are compared with information taken from the patent systems in use at the time. This useful information on the structures, which may be expanded in future research, clearly describes the relationship between patent specifications and reality.  相似文献   
48.
49.
Cyclic pore pressure response of low plastic fines is examined with regard to factors influencing overall behavior of such soils under repeated loads. A model for pore pressure generation under repeated loads and another model for relationship between cyclic pore pressure and straining are proposed. The models are developed in consideration of an extended database generated through a comprehensive literature review. The models are evaluated based on the comparisons between predicted and measured pore pressure responses.  相似文献   
50.
Inferences about settlement structure play an important role in explanations of social and political change in Late Prehistoric eastern North America, but ethical and logistical challenges posed by extensive horizontal excavations mean that archaeologists must develop low cost, minimally invasive methods for investigating key properties of village structure. There are two important components of most villages in the region: 1) the peripheral distribution of middens; and 2) the size and location of formal communal spaces or plazas, each of which leaves traces in soil chemistry. In shallowly buried, plowed village sites where artifacts have been physically displaced, the chemical signature of middens may be more resistant to disturbance and provide an enduring signature of ancient settlement structure. We conducted a systematic soil phosphorus survey at the Reinhardt Site (33PI880) in central Ohio, the primary occupation of which occurred during the Late Prehistoric Period (ca. AD 1200-1450), to test for the presence and approximate size of a central plaza and the shape and distribution of peripheral midden deposits. Soil samples from the modern plowzone (N = 131) were analyzed for Mehlich II extractable phosphorus using molybdate colorimetry. The interpolated phosphorus distributions indicate a clear ring midden approximately 90 m across with an internal plaza that is roughly 30 m × 40 m. Artifact distributions from a shovel test pit survey and interpolations of plowzone magnetic susceptibility measurements identify the location of the village but are ambiguous with regards to village size and do not clearly distinguish the central plaza. Our results suggest that systematic surveys of soil phosphorus are a rapid, minimally invasive, and inexpensive method for generating data on the size and shape of villages and their plazas.  相似文献   
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