Axial Force Estimation in Historical Metal Tie-Rods: Methods,Influencing Parameters,and Laboratory Tests

This research focuses on estimating the axial force of historical metal tie-rods by means of non-destructive testing (NDT) which provides useful information for calibrating structural models. The first part of this work describes the behavior of tie-rods, emphasizing the key role played by cross-section stiffness, which is usually neglected in the case of cables. Particular attention is then given to common effective parameters and dynamic aspects in terms of acquiring the set-up and which modal parameters to examine.

For new insights into methods for assessing historical tie-rods and evaluating the reliability of analytical and numerical predictions, laboratory tests on four samples with typical cross-sections were carried out on historical metal tie-rods. A set of 224 configurations, including various methods of excitation, boundary conditions, and stress states, were analyzed. In addition to laboratory parameters, this analysis also includes details of sensor positions and number of modes to be examined, and proposes a simplification for less time-consuming tests on-site.     

Experimental Characterization of Ancient Metal Tie-Rods in Historic Masonry Buildings

Metal tie-rods play a decisive role in the control of horizontal thrusts in historic masonry buildings. The main goal of the present study is to investigate the relationship between metallurgical and mechanical properties of original tie-rods in order to contribute to a wider study on ancient building stability and their restoration protocols. This article presents the results of an experimental test campaign carried out on 14 historic tie-rods (dating back from 16^th–19^th century) recovered from restoration works or building demolitions. Stress-strain mechanical tests showed that the elastic modulus of the material is comparable to that of modern structural steel, while the strength and the elongation capability are significantly lower, with a large scatter. Further analyses based on metallography allowed us to assess that this mechanical behavior depends on the heterogeneous nature of the material, which can eventually be compared to a composite with vitreous elongated particles in a ferritic or ferrito-pearlitic matrix. The origin of such metallurgical condition is related to the iron making based on direct smelting from ores.     

Earthquakes and Tie-Rods: Assessment,Design, and Ductility Issues

The effectiveness of tie-rods is widely stressed in past earthquakes and they are still used today as reinforcement intervention, given that their use is a low-invasive and low-expensive technique. However, the earthquake design of these devices is not so simple since the main feature of a tie-rod derives from its ductility and that should be preserved as was done in the past. In this article, some considerations about static and seismic design of tie-rods are made, highlighting the main failure modes of the system. To assess seismic vulnerability of I-mode mechanism, displacement-based methods are usually used, requiring high elongation capability of the tie-rods. For this reason, an experimental campaign was carried out to define clearly the maximum elongation of tie-rods and to investigate the influence of bar length on ductility. The results have shown a good displacement capacity that decreases with the increase of steel strength. A simplified formulation, obtained from nonlinear kinematic analysis, is derived to evaluate quickly the seismic vulnerability of I-mode mechanism with tie-rods and to design this common retrofitting intervention in existing buildings.     

泰州水关遗址结构分析及修缮设计

水关是古城墙建筑的一个重要元素,对研究古城墙布局及城市演变具有重要意义。为了对泰州水关遗址进行科学保护,首先通过现场调研,对泰州水关遗址的残损进行分析,找出其可见的病害,包括墙体残损、基础残损、券体残损及木桩残损;然后通过有限元模拟分析其结构性能,找出其隐在的病害,主要是地基和墙体问题。最后,综合残损调研及数值模拟结果,提出了适用于水关遗址的修缮设计方法,包括地基加固、墙体加固以及木桩保护方法。     

青年农民工就业质量问题的实证研究——以长沙市为例

通过对长沙市301名青年农民工的实证研究表明,青年农民工的就业质量偏低,且受人力资本、社会资本和社会制度的影响显著。要提高青年农民工的就业质量,必须加大青年农民工的人力资本投入,努力扩展青年农民工的社会资本,不断完善现行的社会制度体系。     

Evaluation of Structure from Motion Software to Create 3D Models of Late Nineteenth Century Great Lakes Shipwrecks Using Archived Diver-Acquired Video Surveys

Here we demonstrate the ability to use archived video surveys to create photorealistic 3D models of submerged archeological sites. We created 3D models of two nineteenth century Great Lakes shipwrecks using diver-acquired video surveys and Structure from Motion (SfM) software. Models were georeferenced using archived hand survey data. Comparison of hand survey measurements and digital measurements made using the models demonstrate that spatial analysis produces results with reasonable accuracy when wreck maps are available. Error associated with digital measurements displayed an inverse relationship to object size. Measurement error ranged from a maximum of 18 % (on 0.37 m object) and a minimum of 0.56 % (on a 4.21 m object). Our results demonstrate SfM can generate models of large maritime archaeological sites that for research, education and outreach purposes. Where site maps are available, these 3D models can be georeferenced to allow additional spatial analysis long after on-site data collection.     

五种含氯铜合金腐蚀产物的拉曼光谱及扫描电镜的分析研究

为深入研究五种含氯铜合金腐蚀产物(氯铜矿、斜氯铜矿、羟氯铜矿、氯磷钠铜石和铜氯矾)的拉曼光谱图,进一步补充金属锈蚀物的拉曼光谱库,采集不同考古来源的铜合金上腐蚀产物的拉曼光谱,并结合扫描电镜观察了腐蚀产物的形貌特征。研究结果表明,氯铜矿、斜氯铜矿和羟氯铜矿3个同分异构体的拉曼光谱并不相同:氯铜矿和斜氯铜矿较为常见,且经常混合在一起;羟氯铜矿不稳定,非常少见,一般与其他两种混合在一起。扫描电镜观察氯铜矿主要为粒状形貌,同时也发现有葡萄状、皮壳状、钟乳状等形貌;羟氯铜矿因少见,目前只观察到板状形貌。氯磷钠铜石腐蚀产物较厚且疏松柔软,常发现于干旱地区有动物或人遗骸墓葬的出土器物上,扫描电镜观察呈花瓣形状的蓓蕾形貌。铜氯矾更为少见,笔者目前只在2件器物上发现。同时对5种腐蚀产物的形成原因进行了讨论。     

"人文奥运"与北京历史文化知识教育普及状况调查

通过对北京市民关于2008年奥运会相关知识掌握情况的调查,表明目前北京市民对"绿色奥运"的认知度较高,对"人文奥运"、"科技奥运"的认知度相对较低;而关于市民对北京历史与文化知识的调查,表明市民们的北京历史文化知识水平普遍偏低,且市民们大都乐于获取相关知识.因此,采用多种途径普及"人文奥运"及北京历史文化知识,是当前需要深入开展的重要工作.     

通古斯巴西古城遗址土体特性及PS加固试验

通古斯巴西古城遗址是新疆重要的土遗址之一,原为唐龟兹驻兵的安西都护府所在地。遗址中曾出土大批文物,对于研究西域的屯垦历史和古代城址布局等有重大意义。为了系统地研究了通古斯巴西古城遗址土的工程特性,在实地调查的基础上,通过室内试验对通古斯巴西古城遗址土的物理、力学、水理和化学性能进行测试。此外,还测定了不同PS浓度加固后遗址土重塑土块抵抗风蚀雨蚀能力的差异,进一步确定了PS的渗透加固措施对土质文物的防风化及雨蚀效果。结果表明,7%的PS溶液防风化抗雨蚀效果要更为显著。研究结果可为PS的施工应用提供依据。     

Apollo and the Virgin: The Changing Meanings of a Sacred Site on Anafi

The ruins of an ancient Greek temple on a Cycladic island form part of an Orthodox Christian shrine. To local people and returning migrants, the site is that of their patron saint; its pre‐Christian past is irrelevant except in so far as it establishes their specific link with the ancient world, and thus with national claims of unbroken continuity between modern and ancient Greece. To early travellers and antiquarians, and to today’s archaeologists, it has been primarily the ancient site which is of interest, while tourists are more concerned in finding “an unspoilt island”. A historical survey of information about the ancient and the Christian site reveals ambiguities and confusions about both. These multiple meanings for locals and scholars are discussed.     

Comparison of coordinate measurement precision of different landmark types on human crania using a 3D laser scanner and a 3D digitiser: Implications for applications of digital morphometrics

A total of 11 340 Cartesian coordinates of 42 homologous landmarks on five excavated human crania were recorded by three observers using a three‐dimensional (3D) digitiser and computer models created with a 3D laser scanner. The aim was to compare the errors of the coordinate data of landmarks of different types recorded with these two techniques. The results showed that digitiser‐based and 3D model‐based coordinate measurements had overall standard deviations of, respectively, ±0.79 and ±1.05 mm. However, the 3D digitiser yielded the most precise coordinate data for landmarks defined primarily by biological criteria (Type I landmarks), while the 3D laser scanner models yielded the most precise coordinate data for landmarks defined primarily by geometric criteria (Type III landmarks). These findings are likely to influence the research design of future craniometric studies, as they indicate that the suitability of certain landmark types as reference points for geometric operations, such as partial Procrustes analysis, depends on the method by which they are measured. This information is particularly important for retrospective research or for combined databases such as FORDISC or CRANID, which may integrate different types of landmarks recorded by different researchers and/or instruments. Crania displaying poor preservation and surface discoloration yielded larger measurement errors, especially for the 3D model measurements. This is not surprising given that landmarks on 3D models cannot be located using tactile means, but have to be located solely on a visual basis. Nonetheless, even though the digitiser measurements exhibit an overall precision slightly greater than the 3D model measurements, both techniques yield coordinate data with a precision sufficient for most craniometric research. Copyright © 2010 John Wiley & Sons, Ltd.     

Canary islands aborigin sex determination based on mandible parameters contrasted by amelogenin analysis

Sex determination using mandible parameters is population dependent. In order to assess which measurements better characterize sex in prehispanic individuals from the Canary Islands, we blindly contrasted the results obtained by visual inspection and osteometric measurements with those obtained by molecular sexing using amelogenin ancient DNA analysis on teeth from the same material. Unambiguous sex classification was achieved by amplification of sex specific amelogenin alleles in 56 out of 76 mandibles (73.78% of the cases). Visual inspection led to a correct diagnosis in 66.04% of cases, with a greater proportion of errors for female (54.17%) than male (17.24%) mandibles. Osteometric measurements were able to assign sex correctly in 72.2% in the best of cases (mandibular height), a proportion similar to that obtained using a discriminant function (71.2%). By logistic regression analysis, ramus breadth, index ramus breadth/ramus height and mandibular length were the parameters independently related with a mistaken diagnosis of female sex, whereas bigonial width, ramus height and mandibular length were the parameters more closely and independently related to a mistaken diagnosis of male sex. In conclusion, diagnosis based on visual examination of the mandible or on its metric measurement only serves to roughly estimate sex with an accuracy of around 70% or less, at least among the prehispanic population from Gran Canaria. Amplification of amelogenin alleles leads to unambiguous identification of male and female alleles in 73.68% of cases, at least among the prehispanic population from Gran Canaria.     

Application of Shape Memory Alloys in Historical Constructions

A device prototype, based on the superelastic properties of Shape Memory Alloys (SMAs), is proposed to enhance the thermal and seismic behavior of steel tie-rods. First, the thermal behavior of steel tie-rods with and without SMAs is presented based on the results of extensive experimental tests in thermal room. Next, the seismic performances of the proposed SMA system are discussed based on the results of a series of shaking table tests on a 1:4-scale timber roof truss model. In this article, the functioning principles of the proposed SMA-based device prototype are illustrated and the main aspects related to its implementation in practice are discussed in detail. Finally, a recent example of application of the proposed technology to a historic single-aisle church, realized in the 13th century in Brindisi (southern Italy), and equipped with inadequate and deteriorated steel tied rods, is shown.     

Historical Use of Metal Tie-Rods in the Italian Territory: Treatises,Essays, and Manuals through Four Centuries of History

The use of metal tie-rods in buildings is documented and visible in many Italian areas since the 15th century. This article refers to the study of treatises, manuals and essays from the 15th to the early 20th century, mainly in the Italian context with some exceptions of certain foreign texts that, due to their diffusion and importance, have greatly influenced the technical literature on the subject. Technology is an expression of the social, economic, cultural, political and juridical events of a country and, as such, is deeply linked to the times and territories in which it develops. However, it is also closely linked to the laws of nature and to forms of communication, therefore it is useful to compare, underlining the analogies and differences, the knowledge and the ways of the productive and technical process in a long-term analysis.     

The heritage tourist: an understanding of the visitor experience at heritage attractions

This study seeks to explore the visitor experience at heritage sites pre, during and post visit. A conceptual model depicting the heritage visitor experience was proposed. A self-administered survey (n?=?195) was completed by visitors at six heritage sites across Northern Ireland. Visitor characteristics and pre-experience were analysed and results showed that heritage visitors are primarily motivated by recreation and base their visitation decision on advice from friends and family. Results from the exploratory factor analysis showed that audio and visual communication, atmospherics, on-site engagement, information and heritage preservation were the most influential factors during a visit. Post-experience results indicate that 54% of the sample was satisfied with their visit and 85% would revisit the heritage site. The final model suggests a range of factors which positively contribute to the visitor experience at heritage sites though this requires further testing.     

Sex identification of ancient DNA samples using a microfluidic device

A microfluidic device has been developed for the sex identification of ancient DNA samples and works by manipulating liquids within an environment of micrometer dimensions. In this work a range of microfluidic DNA extraction methods were evaluated for their compatibility with ancient DNA samples, and the use of streptavidin-coated super paramagnetic particles to isolate biotin-labeled abasic sites within damaged DNA was shown to be the most reproducible. Polymerase chain reaction-based DNA amplification was possible on the microfluidic device when less than 50 pg of template DNA was added. As a proof-of-principle, powdered bone samples were analysed using the integrated methodology developed. Following conventional capillary gel electrophoresis, two out of the three samples produced positive amplification results and were successfully identified as female. These sex identifications were corroborated by independent Amelogenin, anthropological and Y chromosome analysis. The work reported here is the first step in the development of a complete miniaturized microfluidic system that would enable on-site ancient DNA analysis.     

Dynamical Assessment of the Work Conditions of Reinforcement Tie-Rods in Historical Masonry Structures

Tie-rods are essential structural elements, which have been employed for centuries in masonry historical buildings, either during the construction or in successive strengthening interventions, with the aim of containing dangerous horizontal actions. The actual work conditions of these tie-rods, which are strongly influenced by their load history, are difficult to be quantified theoretically, and an effective method for their measure is of great importance in order to ensure the efficiency of these elements during the time and the stability of the entire building. Common measurements are often carried out adopting models based upon significant simplifications, like, for example, hinges at the extremities. These assumptions, rarely represent the real work conditions for anchorages. In this work, a non-destructive testing method is presented, based upon sophisticated dynamical models that can take into consideration many of the circumstances neglected by the simplified models. Four case studies are extensively described, trying to embrace the most common situations in term of peculiar features of the building, structural configuration, and load history. The discussion of the results yields the safety margin of the rod with respect to the material failure and provides important indications about the overall stability of the whole building.     

珂罗版复制在书画文物保护中的作用

珂罗版印刷是一种古老而精妙的平面印刷技术,珂罗版印刷在印刷复杂的书画作品时,特别是在中国古代书画的笔触和墨韵表现上,可以最大限度地体现原作的艺术特色,达到其他印刷手段难以企及的艺术境界。珂罗版印刷与人工设色相结合,提高了人工临摹的工作效率使古老珂罗版印刷更具艺术生命力,成为复制书画文物的最佳手段。     

A Multidisciplinary Strategy for the Inspection of Historical Metallic Tie-Rods: The Milan Cathedral Case Study

A reliable assessment of historical metallic tie-rods requires both the estimation of actual tensile load and the identification of dominant defects. Despite high defectiveness resulting from traditional metalworking techniques, so far the latter aspect has not been duly addressed in the literature. In this article, several methodologies are discussed aimed at integrating the usual inspection practice. All studies were performed on the tie-rods of Milan Cathedral. Metallurgical analyses allowed to recognize the main features of the material. Mechanical characterization in the perspective of Elasto-Plastic Fracture Mechanics (EPFM) indicated the conditions for crack propagation. Several Non-Destructive Techniques (NDTs) commonly used in Mechanical Engineering (i.e., guided waves, eddy currents, pulsed active thermography) were examined and adapted to this unconventional application. Based on the combination of all the mentioned methods, a multidisciplinary procedure was defined, which allows the evaluation of the crack significance with reference to the estimated working stress.     

欧洲传统书口镶金工艺

传统书口镶金工艺是一种在欧洲传统手工豪华精装书中使用的书籍装饰工艺,经过一系列工序后,可使书口呈现金色镜面的效果。近年来,随着国内西文古籍修复工作的逐步开展,修复人员需要面对的书口镶金类西文古籍会越来越多,因此有必要对此工艺及其修复方法进行研究与总结。笔者对传统书口镶金工艺的发展简史、主要流程、相关工具、材料、技术参数等进行了较为详细的介绍,可为西文古籍的修复工作提供借鉴。