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1.
Two sets of twelve Portland limestone tablets were attached to carousels outside and under the open, lightweight shelter at Bishop’s Palace (Witney, England) for 18 months to assess the influence of shelters on soiling and microbiological growth on stone. At the start, and at 6-month intervals, tablets were analysed using microscopy (optical and SEM), colour measurement (spectrophotometry), weight change measurement and salt content determination (ion chromatography). Concentrations of NO2 and SO2 were also monitored for a month using diffusion tubes. In addition, results were compared with those obtained by the UK National Materials Exposure Programme (NMEP) on chemical weathering rates. Differences in soiling and biological growth on sheltered and unsheltered samples, and their influence on limestone decay were established. The shelter is likely to reduce biological growth by modifying the micro-environmental conditions. However, it may also exacerbate dust deposition, which might increase decay rates in the long-term.  相似文献   
2.
Recent research has studied the effects of seasonal variability on waterlogged burial environments. In a new approach to the study of archaeological contexts, the use of controlled laboratory conditions via lysimeters has enabled new insights into the nature of short term fluctuations in saturation, and the impact that these can have on burial contexts. In addition, the protocols used have facilitated interesting insights into burial environments and the way in which fluctuations in saturation and seasonality can impact on the contained organic components within them.  相似文献   
3.
In the prehispanic Gran Canaria there are some anthropological differences between the coastal inhabitants who buried their dead mainly in tumuli, and those from the central mountains, mainly buried in caves. Some data, as the prevalence of auricular exostoses, and a different bone Ba/Sr ratio support the view that there were differences in economy and diet between both groups of islanders. Moreover, the proportion of carious teeth was significantly higher among the population buried in caves. In the present study we analysed the prevalence of dental calculus, periodontal disease and antemortem tooth loss in remains of 791 individuals belonging to the anthropological collection of the Museo Canario (Las Palmas). Calculus deposition was very frequent (88.51%), no differences existing between men and women or between those interred in tumuli or in caves. Age at death was the only parameter independently related to calculus deposition by stepwise multivariate analysis. Periodontal disease was observed in 66.78% of the population, significantly more in men (χ2 = 4.88, P = 0.027). No differences existed between individuals buried in tumuli and in caves. Antemortem teeth loss was observed in 64.73% of individuals, no differences existing between men and women or between those interred in tumuli or in caves. There was a significant association between calculus and periodontal disease (χ2 = 18.07, P < 0.0001). Both caries (χ2 = 8.40, P = 0.004) and periodontal disease (χ2 = 44.96, P < 0.0001) were associated with tooth decay. However, the proportion of teeth with calculus deposition (in relation to observed teeth) was significantly higher among the population buried in tumuli (Z = 3.18, P = 0.001), although no differences were observed when the proportion of antemortem lost teeth and alveoli with periodontal disease were compared among people buried in tumuli and in caves, but women showed significantly lower proportions of alveoli with periodontal disease and antemortem tooth decay. These data suggest that the population buried in caves had a different dietary pattern to that of those buried in tumuli, since calculus deposition -more frequent in the latter-may be related to the consumption of proteins. The results also point to the existence of differences in diet between men and women.  相似文献   
4.
Timber structures can be degraded during their life both by structural problems and by biological degradation factors like fungi and insects. The occurrence of those biodegradation agents could lead to a loss of their structural integrity, in the absence of appropriate maintenance. An early assessment of the decay is even more important when the wooden structures are part of historical buildings, in the interest of conservation of cultural heritage.

This article presents an application of microwave reflectometry for the in situ evaluation of timber structures. The measurement system allows detecting anomalies inside the material in a non-destructive and non-invasive manner.

The reflection coefficient is measured by means of a vector network analyzer (VNA) using a double-ridge antenna which transmits the continuous-wave (CW) microwave signal and receives the signal reflected by the material under investigation.

Measurements on laboratory models demonstrated the feasibility of the method. Results obtained on timber beam sections, compared with the findings of traditional investigation methodologies, demonstrate the potentiality of microwave reflectometry, suggesting its possible usefulness during the diagnostic phase as a non-invasive tool for preliminary screening.  相似文献   

5.
Henry Tudor’s diffusion of power in the English far north, and his savage pruning of resources for his wardens there to maintain good rule and defence, were perhaps necessary steps initially to prevent further challenges from overmighty subjects. Twenty years later, this was no longer an issue; and once peace with Scotland collapsed, the absence of the region’s traditional ruling magnates was keenly felt. Under Henry VIII, an obscure border baron, Lord Ogle of Bothal, was often Northumberland’s only resident lord, precipitating a crisis of lordship described as ‘the decay of the borders’. Unable to recruit as warden a reliable magnate on acceptable terms, Henry VIII then decided that, as a matter of principle, he would ‘not be bound, of a necessity, to be served there with lords’. The King appointed himself as warden-general, delegating the real work to gentlemen deputy wardens whose manraed was enhanced by feeing other leading local landowners, including Lord Ogle. Ogle’s kin and connection thus supplied successive wardens with an adequate following in peacetime; but in the ensuing war Ogle was overwhelmed with his warden on Ancrum Moor, becoming the only nobleman in England under Henry VIII to die in battle.  相似文献   
6.
Additivating mortars with crystallization modifiers is a novel approach to mitigate salt crystallization damage in historic masonry. Once verified the effectiveness of crystallization modifiers in bulk solution, the next step consists in verifying whether: (i) modifiers are still effective when mixed in mortar and going through the carbonation process and (ii) modifiers alter any mortar properties which might limit their application. This research addresses these issues for sodium ferrocyanide and borax, modifiers for sodium chloride, and sodium sulfate, respectively. Several experimental techniques have been applied to elucidate these questions. The results show that the selected modifiers are still able to alter the salt crystallization after going through the carbonation process of the mortar. Besides, no major effects of the modifiers on the fresh and hardened mortar properties were observed. It can therefore be concluded that there are no restraints for the future use of these crystallization modifiers in restoration mortars.  相似文献   
7.
Mount Nemrut is a 2,206 m high mountain located in Adiyaman, Turkey. A number of monumental statues, a 50-m high tumulus, and a lion horoscope were constructed at the top of the mountain by King Antiochos I (69–36 bc) of the Commagene Kingdom. The site was included in the UNESCO World Heritage List in 1987 due to its unique character. However, the limestone statues located on both the east and the west terraces of the site are getting deteriorated. This study investigates the weathering of the limestone at Mount Nemrut based on field and laboratory studies. It is found that the dissolution occurs along microcracks developed in the limestone during geological time. It is more pronounced in the east terrace where freezing-thawing cycles are more than the west terrace. Furthermore, dissolution is more effective for the faces of the statues exposed to direct atmospheric contact. Due to harsh atmospheric conditions with dominant wetting-drying and freezing-thawing processes at the site, it is recommended that direct rain and snow contact with the statues should be minimized.  相似文献   
8.
This paper presents a differential diagnosis of pathological changes observed in the deciduous dentition of a child aged 3–4 years, recovered from a Late Roman (c. ad 270–410) cemetery at Ancaster, England. The entire maxillary dentition exhibited areas of missing enamel and erosion of the underlying dentine, which was most pronounced at the lingual surfaces of the anterior teeth, and lingual and occlusal surfaces of the molars. Additionally, the mandibular second molars and mandibular right first molar displayed superficial enamel erosion of the buccal surfaces. Radiography indicated normal enamel density, and no further dental pathology was identified. Conditions considered in a differential diagnosis included amelogenesis imperfecta, fluorosis, perimolysis, xerostomia‐related caries and early childhood caries (ECC). The nature and distribution of lesions implicates ECC – also known as ‘nursing caries’ or ‘baby‐bottle caries’ – as the most probable diagnosis. The potential significance of the findings for studies of infant health and feeding practices in past populations is discussed. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
9.
旧城中心区城市衰落研究——以广州沿江西区域为例   总被引:2,自引:0,他引:2  
在广州这样城市化水平高、经济发展快的华南大都市,也在城区的部分地段出现了城市衰落与更新现象。本文以沿江西RBD为例分析广州城市衰落现象的表征和原因,从物质形态和非物质形态两大方面对沿江西RBD的城市衰落现象进行分析,认为该地区交织存在着结构性衰退、功能性衰退和物质性老化。  相似文献   
10.
旅游流距离衰减现象演绎研究   总被引:13,自引:1,他引:12  
以旅游系统空间结构模型为依托,通过绘制旅游流距离衰减曲线,对旅游流距离衰减现象进行演绎研究。结果发现,高斯分布型和指数分布型是旅游流距离衰减曲线的基本类型,旅游系统中客源地结点的空间分布格局是旅游流距离衰减曲线类型的决定性因素,到访率距离衰减速率是曲线形状的修饰性因素,距离衰减曲线的绘制方法不同,距离衰减曲线的类型也不同。最后,以井冈山和庐山为案例进行了实证分析。  相似文献   
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