Salt Effects in Plastered and Unplastered Outdoors Brick Masonry: Quantitative Laser Monitoring of Surface Decay Evolution

In masonry materials, the superficial decay is a widespread problem. Aggressive environmental agents such as moisture and salts trigger the damage by propagating through the material capillary pores. Although several studies have been carried out on salt crystallization and their damaging effects, additional research effort is required to better investigate this phenomenon on real cases and real weathering conditions. To this purpose, testing and monitoring tools capable of following degradation process since the early beginning are necessary. Repeated visual inspections are commonly used to monitor the superficial decay, but this technique is subjective and thus not capable of providing any quantitative information. In this work, an experimental campaign, carried out in Bologna, Italy, is presented. A two-header brick wall, one main face unplastered and one plastered, was stored outdoors and exposed to weathering over two summers. Before the start of the second aging season, moisture and salt capillary rise was simulated by low-concentrated sodium chloride solution (0.1% -wt). The aim was to favor solution evaporation and salt crystallization and to provoke material damage. The degradation process was monitored based on a contactless, rapid and accurate image diagnostic technique. In particular, high-resolution laser scanning by triangulation technique was adopted. Three-dimensional data acquisition was repeated at the end of both seasons. The proposed procedure successfully extracted quantitative information approximately areas of material spalling and detachment even in the initial phases of decay.     

Importance of Monitoring,Behavior Analysis,and Diagnostic Techniques for Preservation of Great Historical Structures

A synthetic overview is presented of the motivations, technological possibilities, and benefits of the practice of providing large structures with monitoring installation and interpretative activities. Starting from the large body of experience gained in the field of dam engineering, the gradual penetration of these techniques in the area of preservation of monumental building is surveyed. Particular attention is dedicated to the case of the Brunelleschi Cupola in the Florentine Cathedral of Santa Maria del Fiore. The more pressing needs for the next-future development of these studies and practices are then enunciated, with the auspice that the obstacle posed to their diffusion by the difficulty of collecting adequate financial funds may be overcome in the best interest of the conservation of a precious historical-cultural heritage.     

The Danish 17th-Century Man-of-War Stora Sofia: Documentation and in situ Preservation

In 2002 Bohusläns museum, Sweden, conducted archaeological recording of the Danish man-of-war Stora Sofia , which foundered in 1645 just outside Gothenburg on the Swedish west coast. This was followed by an in situ preservation project involving a protective covering and a monitoring protocol. After three years of intensive monitoring the results are satisfying. In particular, the wooden samples show obvious differences in deterioration between the exposed outside environment and the newly-protected site. As well as preserving the remains of Stora Sofia , the project also represents the beginning of a more active regional strategy in marine in situ preservation.
© 2009 The Author     

A Strategic Framework for Monitoring Coastal Change in Australia's Wet-dry Tropics – Concepts and Progress

A strategic framework for monitoring natural and human-induced change in the coastal plains of the Alligator Rivers Region in the wet-dry tropics of northern Australia is presented. The framework also supports refinement of methods used to monitor the vulnerability of coastal areas to change, including human-induced climate change and sea-level rise. The information derived through the framework can be used to assess scenarios, highlight the potential significance and implications of changes, and assist land managers formulate management responses. The framework incorporates several large-scale studies for monitoring atmospheric and hydrodynamic processes as well as mapping and monitoring projects specific to environmental change in the freshwater wetlands and the floodplains of the Region. Monitoring is proposed to address processes influencing the stability and rate of change of the floodplain environments. These include large-scale processes, such as inter-annual variability in weather conditions affecting the morphology of the coastal plains, shoreline and riverbank stabilisation, headward expansion of tidal creeks, and salinisation of freshwater basins. Information management is also addressed, and a Geographic Information System structure proposed for effective data collation, analysis and management. The information management system will facilitate data sharing and participation of multiple agencies and organisations interested in coastal change, especially where a landscape perspective or whole ecosystem approach is advocated.     

Monitoring of Shipwreck Sites

A three-year research project, The Monitoring of Shipwreck Sites (MoSS), was initiated in 2001 as a partnership between several European countries: Finland (project leader), Germany, Holland, United Kingdom, Denmark and Sweden. The aim was to establish a suitable programme for the monitoring, safeguarding and visualizing of shipwreck sites, based on the investigation of three wrecks located in the Baltic and North Seas. Phase I involved the monitoring process, with the investigation of physical, chemical and biological factors that will help to identify potential threats to buried and exposed archaeological material. Phases II and III considered safeguarding and visualizing of shipwreck sites.
© 2005 The Nautical Archaeology Society     

Experimental Study on Low-Cycle Fatigue Performance of Weld-Free Buckling-Restrained Braces

A type of weld-free buckling-restrained brace is proposed to eliminate the influence of welding on the low-cycle fatigue performance. The core member is manufactured with no weld existing along the overall length of the member. Three welded and three weld-free specimens under different strain amplitudes were tested, and the hysteretic behavior and low-cycle fatigue performance of the specimens were analyzed. The test results indicate that the ductility and the cumulative plastic deformation of the weld-free specimens are much higher than that of the welded ones, which are much closer to the performance of the material capacity.     

中国国家博物馆环境空气质量监测报告

为加强博物馆藏品的预防性保护,需全面掌握博物馆馆舍内外空气质量的现状,对其进行评估,进而采取有效措施治理改善,妥善保护人类文化遗产。本馆采用美国普滤(Purafil)公司研发并提供的检测技术,在馆舍内外选定八个测试点进行了腐蚀试片测试。根据监测数据得知,本馆处于高浓度极具腐蚀性的二氧化硫气态物质的包围中,已造成对金属、纸张等文物的危害,治理改善收藏环境迫在眉睫。创造保存各类藏品的微环境空间,是治理改善博物馆收藏环境的有效手段。     

高陡濒倾土遗址边坡加固后的变形行为

土遗址边坡加固不同于一般边坡加固是在于其文物属性。对于高陡濒临倾倒的边坡一般采取“去头补脚”的方式进行处理,而对于土遗址边坡须遵从原状保护的原则。土遗址边坡加固后演化过程具有独有的特征。为此,边坡的变形监测资料对分析边坡变形演化规律及边坡稳定性至关重要。采用南瑞大坝全自动变形监测仪对交河故城513亚区濒倾边坡加固后的变形进行实时监测,精度达0.01mm。通过对变形数据分析,阐明其变形行为特征,进而挖掘加固后边坡演化过程。研究表明,加固后边坡表现出明显的非线性特征,具体表现为常态稳变和局部突变特性;变形可划分为明显的趋势性变形、周期震荡式变形和随机性变形。研究结论对于类似土遗址边坡加固效果评价具有重要意义     

温湿度场仿真模拟在博物馆环境监测中的应用研究

针对博物馆当前的环境监测方式无法全面感知温湿度空间分布的问题,本研究引入与数据同化(EnKF)算法相结合的计算流体动力学(CFD)模拟方法,以某博物馆的展厅空间为例,获得可视化的温湿度场仿真模拟结果,并结合藏品保护要求进行数据分析和相关讨论。经与实时监测数据对比,基于数据同化的CFD模拟准确性良好,误差在可接受范围内。本研究引入的技术方法实现了博物馆环境监测从“点监测”到“场监测”的转变,后续可为博物馆藏品预防性保护提供更加科学有效的技术支撑。     

高原地区博物馆经书柜内环境参数稳定性分析

高原地区寒冷干燥,昼夜温差大,日照强,为了研究高原博物馆环境参数的变化情况,对拉萨市某博物馆库房经书柜内外进行为期10个月的温湿度、CO₂浓度、VOC浓度、光照强度和紫外线强度监测,分析了环境参数的变化规律、特征和影响因素。结果表明:柜内温湿度随柜外温湿度季节性变化而变化,柜内温湿度日变化小,温湿度平均日较差分别为0.73℃和0.83%,柜外为1.6℃和4.25%,经书柜可以有效保护古籍文物不受柜外环境温湿度日波动的干扰;柜内外温湿度日较差与季节无显著的相关关系,该博物馆建筑围护结构隔热性能较好;温度日较差与CO₂浓度日较差呈显著的正相关关系,即库房内工作人员越多,温度日较差越大;柜内VOC容易富集,浓度更高,建议放置活性炭等吸附材料;光照和紫外线强度极低,当前经书柜整体有利于保存。