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91.
    
Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow artefacts (δ56Fe = 0.38 ± 0.1, n = 7) and source materials (δ56Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the north-eastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data demonstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopically distinct artefacts.  相似文献   
92.
    
Several authors agree that stone surface consolidation works should not significantly alter original mechanical and hygrometric properties of the stones in order to avoid differential stress between the consolidated and non-consolidated parts. Specific limitedly destructive methodologies have been developed for assessing the variation in both mechanical and hygrometric properties, but they require preliminary calibration procedures that are very costly to adopt in terms of both time and money. This research study describes an analytical and experimental procedure aimed at obtaining the necessary hygrometric and mechanical characterization of natural and/or artificial stone, before and after consolidation works, by simply assessing the variation in the distribution of the porous structure.  相似文献   
93.
    
Built in the first half of the 13th century on behalf of the Emperor Frederick II, the Maniace Castle of Siracusa focuses its enigma in the hypostyle hall (which was composed of 25 quadripartite rib vaults) and the design criteria adopted for its implementation. Recent research and a careful rereading of the documentary “restoration project” after the earthquake of 1693 have offered new tools to understand the construction techniques and building procedures for the entire organism. It has been possible to demonstrate that the different material (white limestone and volcanic stone) used for the vaults is, in fact, a product of reconstruction. The constructive node, which historiography has taken for granted, is now crucial—the documentary evidence of the restoration after the earthquake compared with the materials found in situ provide interpretive keys to decode genesis and procedures of the huge structure built five centuries before.  相似文献   
94.
Rodrigo Gil is one of the greatest masters of Spanish architecture. His brilliant career is partially explained by the efficiency of his design methods and his building techniques, especially evident in his ribbed vaults. If we examine the latter as a whole, the first aspect to be noted is undoubtedly their great formal complexity. However, the detailed study discloses that rather limited geometric and building techniques are hidden behind those elaborated patterns, aimed at simplifying and making the execution more economical. In order to bring some of these devices to light, one of his best-known vaults was selected for an in-depth study. The construction of a large-scale model of it also revealed some interesting features regarding the placing of the centerings and shorings during the erection.  相似文献   
95.
    
Ground-edged artifacts were an important part of the Australian Aboriginal toolkit. They had practical day-to-day uses, but some had symbolic and social values that led to their movement across great distances. Australian provenance studies document long-distance Aboriginal exchange systems extending over hundreds of kilometers. The size and complexity of exchange systems and social networks were contingent upon resources and the productivity of a region's environment. Along the fertile, well-watered lands east of the Great Dividing Range, movement of objects may have been geographically more circumscribed than in drier areas to the west. One hundred and twenty-one mafic, ground-edged artifacts from the New South Wales (NSW) Central Coast and 368 geological specimens from potential sources were non-destructively analyzed by portable X-Ray fluorescence spectrometry. Results indicate the existence of a well-used basalt source within the region at Peats Ridge-Popran Creek as well as multiple local and non-local sources up to 430?km from Mangrove Mountain on the NSW Central Coast.  相似文献   
96.
The ‘Triple R’ approach on the restoration of dry stone walls, using recognizable, reversible and respectful constructive techniques is here illustrated. A set of restoration procedures are explained and applied to a UNESCO World Heritage site in Al-Baleed (Salalah, Sultanate of Oman) in the ‘Land of Frankincense’. The procedures were adapted in an innovative way to take into account the climate features of the Indian Ocean area (specifically, the effects of the monsoon season). All the restoration procedures aimed at conserving the site’s original architectural features by using only suitable stones and materials found on-site. Specific procedures have been adopted to consolidate walls, gates, foundations and sloping surfaces. Simple on-site mechanical tests and evaluation methods have been developed for a quick assessment of the safety level of the restored walls to ease future archaeological excavations. The application is related to a waterfront side of the ancient city built around the ninth century and added to over the next five centuries. These restoration procedures allowed for further archaeological excavations with new findings is here described.  相似文献   
97.
    
ABSTRACT

This article presents numerical simulations of two full-scale masonry structures which were tested on the shaking table within the scope of the workshop “Methods and challenges on the out-of-plane assessment of existing masonry buildings”. The numerical models have been developed on the basis of the blind-prediction models which have been improved after the publication of the test results. The solution procedure is divided into two steps with separate numerical simulations for each one. In the first step the collapse mechanism of the structure is determined by means of pushover analysis using a continuum, plasticity-based model. In the second step the dynamic response of the structure is simulated using a multibody model approach and frictional contacts. Results of the tests show reasonable, yet far from perfect predictive capabilities of the used numerical methods.  相似文献   
98.
    
ABSTRACT

Considerable change occurred in the Late Holocene Later Stone Age of Namaqualand, northwestern South Africa. Focusing on stone artifacts, pottery, and ostrich eggshell beads, the cultural sequence for the area is described. Two additions are identified, complicating the traditional model for the introduction of herding into the country. From the mid-Holocene onward, lithic assemblages are based on milky and/or clear quartz and cryptocrystalline silica and initially contain many backed tools with scrapers more common during the first millennium BC. These are hunter-gatherer assemblages. During the final centuries BC, backed bladelet-rich assemblages based on clear quartz appear, with the earliest examples demonstrating typological continuity with the existing assemblages. About 1,500 years ago, expedient assemblages lacking retouch and based on poorer quality quartz appear. The three types co-occur during the last 1,500 years, occasionally in combination with one another. This contrasts strongly with other parts of South Africa where just two distinct assemblage types are identified, suggesting that the hunter-gatherer-herder dichotomy is not universally valid. The artifact patterns between about 200 cal BC and cal AD 500 and the introduction of livestock suggest considerable cultural and social change, heralding the onset of a local Neolithic, but the exact mechanisms remain unclear.  相似文献   
99.
    
M. Wojcieszak  L. Wadley 《Archaeometry》2018,60(5):1062-1076
Micro‐residue analysis of stone tools is generally performed with optical light microscopy and the visual observations are then compared with experimental, replicated pieces. This paper complements such archaeological research by providing physico‐chemical evidence. Raman spectroscopy and scanning electron microscopy have been used to confirm the presence of hematite on red‐stained medial and proximal parts of 71 000‐year‐old Still Bay bifacial tools from Sibudu Cave. Our results confirm the conclusion from optical light microscopy that the tools were hafted with an ochre‐loaded adhesive. However, we point to some instances when hematite residues are incidental or may be inclusions in the rock used to make the stone tools.  相似文献   
100.
试论西夏雕像石座   总被引:2,自引:0,他引:2  
位于宁夏贺兰山东麓的西夏皇家陵园 ,蕴藏着丰富的石刻雕像 ,内容多样 ,形象生动。就其风貌而言 ,其中的雕像石座尤具特点 ,独树一帜。 2 0世纪 70年代以来 ,出自西夏帝王陵碑亭遗址中的雕像石座计有 1 1件 ,现介绍如次。一、石座形制西夏陵区中雕像石座的出土情况如下。9号陵 (原编 1号陵 )西碑亭石座 :1 972年发现 ,共出土 4件 (L9XBZ1~Z4 )。现 2件藏宁夏博物馆 ,另 2件入藏西夏博物馆。此 4件石座均为赭色沙岩质 ,略呈圆柱状方体。长宽尺寸为 59厘米~ 6 2厘米 ,通高 6 2厘米~ 6 4厘米 ,其中底部“土衬”高7厘米~ 9厘米。造型基…  相似文献   
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