The original fineness of coins is very important information that can help us to understand the commercial situation in a wide historical context. This paper deals with a comparison of analytical methods suitable for the evaluation of the actual and original fineness of coins based on a detailed case study of a medieval coin sample. Both non‐destructive (i.e., scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, X‐ray fluorescence, atomic force microscopy and hydrostatic weighing) and destructive (i.e., inductively coupled plasma – mass spectrometry and the Volhard titration method) techniques were used. The original fineness can be also deduced from knowledge of the internal structure of the coin (limited miscibility of copper and silver). A new analytical method based on a combination of a micrograph of the metallographic cross‐section with consequent image analysis was developed for determination of the original fineness. The proposed approach is relatively simple and provides reliable values. Sample heterogeneity and its impact on the determination of fineness are also discussed. 相似文献
As social and cultural contexts change and globalization spreads, the number of transnational-marriage migrants mainly from Southeast Asia has increased in Taiwan. Using institutional ethnography, this article investigates the roles of local non-governmental organizations (NGOs) and projects aimed at helping foreign spouses to adapt to their new life. I mainly elaborate that NGOs emerge as important actors in assisting and empowering transnational spouses to ‘become locals’. In empowerment projects, foreign spouses are given a voice to elaborate themselves. However, this article elaborates that these projects are a scheme of education to shape each such migrant into a proper ‘Taiwanese wife/mother/daughter-in-law’. Also, these projects particularly promote ‘exoticism’ of migrants and become key sources of how local people understand the images of ‘foreign spouses’. As a result, though NGOs play positive roles in empowering foreign spouses, we need to be aware that NGOs’ efforts may ironically become a mechanism to strengthen transnational spouses’ gender roles and cultural stereotypes. 相似文献
The quick and accurate identification of post-earthquake rescue objects can minimize the casualties and property loss caused by earthquakes. With the rapid development of remote sensing technology, rescue objects can be identified through high-resolution remote sensing images. There are two main categories of approaches to identify rescue object through high-resolution images: automatic extraction by a computer and visual judgment by professionals. Although results can be obtained quickly by using automatic extraction, the accuracy of the results is unacceptably low. For visual judgment, the large demands for time and professionals restrict its wide practical application. In this study, we introduce crowdsourcing into the identification of post-earthquake rescue objects. First, we integrate the advantages of the computer and crowdsourcing, which means that the computer takes advantage of the speed of information processing, while crowdsourcing makes full use of human recognition capabilities. Second, we take visual judgment tasks out of the hands of professionals and entrust the tasks to workers in a crowdsourcing platform. Not only are the human resources infinite, but we can also improve the efficiency of identifying rescue objects. Third, we propose a crowdsourcing model that improves the quality of the results and saves human resources. Finally, experimental results demonstrate that our solution is feasible. 相似文献
The recording and 3D modelling of complex archaeological sites is usually associated with high capital and logistical costs, because the data acquisition must be performed by specialists using expensive surveying sensors (i.e., terrestrial laser scanners, robotic total stations and/or ground‐penetrating radar). This paper presents a novel, low‐cost, user‐friendly photogrammetric tool for generating high‐resolution and scaled 3D models of complex sites. The results obtained with unmanned aerial vehicle (UAV) photogrammetry of an archaeological site indicate that this approach is semi‐automatic, inexpensive and effective, and that it guarantees quality. 相似文献
A major advantage of satellite remote sensing is that the imagery acquired provides a synoptic view of the landscape. Thus, repeat coverage by the satellite on a regular basis permits the detection of changes in land‐cover over time. This study demonstrates the application of remote sensing technology to the monitoring of mining activities at the Athabasca Oil Sands region of Alberta, Canada. First, we describe the techniques used to match a time sequence of Landsat imagery, both spatially and spectrally, to ensure that the spectral changes through time are due to land‐cover variations. A series of spectral trajectories were then extracted to assess changes in land‐cover through time. Secondly, a land‐cover classification was produced from the baseline 1984 imagery and, using historic and future mine extents, the classification was analyzed to determine the proportion of each land‐cover type affected through development. Results of the analysis indicate that since 1984 there has been a larger reduction in mixedwood dense and broadleaf vegetation classes than mixedwood sparse or dense conifer stands in the area. Based on the delineations of mine‐site activity, the area of woodland and wetland habitat subject to development has increased from approximately 2,520 hectare (ha) in 1984 to 32,930 ha in 2005. 相似文献
Although the close association of word and image in medieval cartography is widely acknowledged, the significance of the relationship after the rediscovery of Ptolemy's Geography and throughout the Renaissance has been overlooked, despite Abraham Ortelius's choice of the term ‘Reader’ for users of the Theatrum orbis terrarum (1570). In this paper, the map of the world, which (as in Ptolemy's Geography) opens Ortelius's Theatrum, is analysed to show how Ortelius's concept of space was very different from Ptolemy's. Attention is drawn to the content of the texts on the map, to Ortelius's notion of geography as the eye of history, and to the importance in the Renaissance of the emblem as a conceit, or device, in the system of acquisition and transmission of knowledge. As in emblems, the words on Ortelius's map are not there to explain or to comment on what is seen but to give the image meaning; the purpose of the map is to invite contemplation of God's world. The map is contradictory, however; for Ortelius's accurate and up‐to‐date presentation of the physical world is qualified by a verbal statement that the world is ‘nothing’, a mere pinpoint in the immensity of the universe. It is concluded that Ortelius was not a geographer in the same way Ptolemy was, and that Ortelius was using geography as a philosopher and his world map as an illustration of his moral and religious thinking. 相似文献
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