Integrated and Predictive Systems for Preventive Conservation

ABSTRACT

Forecasting the dynamics of alteration in materials, in particular the timescale of degradation, is relevant to preventive conservation, and great deal of effort has gone into developing new models for the kinetics of physical and chemical phenomena affecting materials. Creating monitoring systems able to assess the evolution of degradation processes that inform intervention programs is necessary to ensure the protection of historical and artistic heritage. The Research Unit for Integrated and Predictive Systems (SIP) is presented: it develops new tools and algorithms to study the alteration of materials using non-invasive techniques and passive monitoring, as well as new mathematical models to predict how the surfaces of materials degrade with time. The paper focuses on the Arch of Augustus and presents initial results from two virtual sensors used to ‘monitor’ environmental conditions outdoors. These systems do not need a permanent, invasive network of sensors in situ. They rely instead on local infrastructure for measuring air quality, and adopt smart information fusion algorithms to predict the environment around the cultural heritage site. Virtual sensors can provide an effective control system that highlights specific conditions linked to specific forms of alteration.     

科技期刊增强科普功能建设面临的问题与路径思考

在新媒体时代,公众阅读兴趣与习惯发生变化,科技期刊若要进一步发展,则可以从增强科普功能的角度来探索有效路径。本文通过分析科技期刊增强科普功能的意义与优势,阐述当前科技期刊所要承担的社会责任。通过分析科技期刊在科普功能建设方面的不足,提出了相应的建设思路:突发事件时进行应急科普;对专业论著进行科普化解读;开设科普专栏;发行科普增刊;充分利用新媒体平台的功能;采用视觉化的科普方式;获取国家政策支持——以此实现科技期刊的经济效益与社会效益的双丰收。     

Mesocycles in conserving plastics

Analysis suggests that progress in conservation of plastics objects and artworks can be described by a series of overlapping mesocycles. Focus has been placed for periods of 5–10 years each on determining the degradation pathways in the 1990s, developing strategies to inhibit those pathways from the late 1990s and, since 2006 on actively stabilizing and treating the symptoms of degradation. The primary driving forces behind the direction and rate of progress within each of these three mesocycles have been different and specific. The controlling factor in understanding degradation pathways for heritage plastics has been the origin of the data describing lifetimes. By contrast, mesocycles in developing suitable storage and display microclimates for plastics have mirrored preventive conservation practices for natural polymeric materials. The rate of the third mesocycle, interventive conservation, has been driven by the need to balance the requirements for reversibility in conservation practices with the artist's intent and significance. Developments within each of the three mesocycles from the 1990s to date are discussed in this article. Environmental science and toxicology of waste plastics offer a novel source of information about real time degradation in terrestrial and marine microenvironments that seems likely to contribute to the conservation of similar materials in contemporary artworks.     

How can science connect with and contribute to conservation? Recommendations and reflections

This paper reports the conclusions and recommendations of the working group that synthesized the discussions on ‘How can science connect with and be of greater benefit to conservation practice?’ during the ICCROM Forum on Conservation Science. The author reflects on these findings from her own perspective and experiences, and places them in the context of two major shifts in heritage research: the first, a shift in focus from conserving materials to managing meaning. The second, a shift in organizational structures from single, centrally funded heritage institutions towards diffuse networks which include new players who have no direct responsibility towards heritage. Both shifts are taking place in an environment of decreased funding and increased accountability to society. Science and conservation connect and contribute to each other most effectively if they together contribute to the societal benefits of heritage. In this regard, heritage science strategies can stimulate collaboration, and direct science and conservation towards innovative, applicable outcomes. Moreover, they can promote a transdisciplinary approach which connects social, economic and business sciences and stakeholders. They should also ensure the creation of sustainable nodes for consolidating knowledge within these dynamic networks.     

Communicating conservation science

What are the key messages conservation science should communicate to the public? Although the profile of conservation science itself can be raised by talking about the process, most feel that the messages should concern what conservation science brings to the focus of its work – cultural heritage. However, it is no longer enough to focus on the needs of heritage in isolation. Demonstrating public benefit is crucial to persuade decision-makers to invest not only in the conservation of cultural heritage but also in the science that informs its care. Conservation science can research the significance of cultural heritage and how to enable access to it, but it now also needs to engage the public actively in its activities. This means continuing to use the traditional ‘hard’ sciences of physics and chemistry but also learning from and collaborating more with less familiar partners such as the social sciences, the medical sciences, and natural heritage to demonstrate how conservation science is good for people, and developing new methods of communication to do this. Conservation science needs to engage with the public not only as a subject for research but also as a means of doing the research, so the end also becomes the means. Public impact should be factored into conservation science projects, with training in communication and the principles of interpretation provided to those involved. A more fundamental shift may be required in the sector however, that puts people's benefit at the heart of conservation science as much as the benefit of the cultural heritage it engages with.     

Long-term changes in climate and insect damage in historic houses

Abstract

Insect pests are an important source of concern in historic houses as the larval stages in particular can feed on a variety of important heritage materials, causing significant and sometimes irreparable damage to collections. Damage to wood and textiles is a special problem. The lifecycles of insects are sensitive to climate and require relatively warm conditions. There has been a significant increase in the presence of insect pests within historic houses in the early twenty-first century. The reasons may include: warmer winters, widespread use of natural fibres, less potent insecticides, and occupation of new niches indoors. The interior climate, especially increasing warmth, offers the potential for greater insect growth and survivability. Modelling changes in the temperature and humidity within the Cartoon Gallery at Knole, southern England, for the period 1770–2100 suggests a dramatic increase in favourable temperature conditions through the current century.     

Frontiers of Preventive Conservation

ABSTRACT

This work considers areas where our present lack of knowledge curtails the effectiveness or efficiency of preventive conservation practice. Mixed media, especially archaeological metals and organics have incompatible requirements for relative humidity (RH). An approach based on understanding the risk versus RH for both materials and considering the showcase performance is elucidated as a solution. Pollution, both the mixed atmospheres around most cultural heritage and the complex, variable nature of deposited particles, are further areas in need of more research. Damage functions and measurement of object deterioration rates are investigated as a path forward, and examples are given.     

The Cathedrals of England: Environmental Performance,Conservation and Exhibitions

ABSTRACT

English medieval cathedrals are a group of buildings of exceptional significance and they contain collections of equal importance. Both the historic building fabric and the artefacts are vulnerable to environmental deterioration. However, unlike buildings owned by heritage organisations, the primary purpose of cathedrals is to further the Christian mission, and the conservation of the building and collections is required to be conducted within these constraints. Increasing visitor numbers and the installation of sophisticated exhibitions makes the task of conservation all the more demanding. Next to mechanical damage, environmental factors are the greatest source of deterioration to sensitive fabric and collections. However, until recently, there has been little systematic study of English cathedral environments and the effects of different uses and control measures. Detailed studies undertaken on 20 cathedrals in the past two decades have provided an insight into their environmental performance and how they differ as a group from many other historic buildings, as well as the passive conservation measures that can be implemented within their primary function.     

Conceptual Model for the Replacement of the Horn of a Nineteenth Century Phonograph

ABSTRACT

3D printing of missing parts of a cultural heritage artifact opens many possibilities and extends the challenges in the processes of intervention on cultural heritage assets. However, restoring these objects may not only mean the replacement of a missing element from its esthetic point of view, but restoring the function for which objects were created. In these processes, the replica of the object must be exact and of quality, but also specific. In this sense, the presented work is a multi-disciplinary attempt to reproduce the missing horn of a phonograph dated to the late nineteenth century. This phonograph belongs to the collection of the ‘Vicente Miralles Segarra’ Telecommunication Museum of the Universitat Politècnica de València. The objective was to recover its esthetic, didactic, and functional levels, i.e restoring its ability to emit sound. To this end, several models were printed with different materials, and the quality of the recorded sound with the different horns was evaluated, assessing their similarity to that obtained from an original horn.     

Enhancing Research Impact in Heritage Conservation

This paper examines how research impact is defined, measured, and generated – with a view to understanding how it can be enhanced within heritage conservation. It examines what is meant by ‘impact’ and how it can be promoted within heritage science through effective inter-disciplinary collaboration. Following a general examination of the current discourse concerning research impact, the study examined: (i) active research networks within heritage science; (ii) research planning and evaluation practices within heritage science; and (iii) the experiences of users (i.e. conservators and other heritage professionals) within research collaborations. Terminologies surrounding the notion of impact and the various phases of the research process were reviewed – from the initial identification of a knowledge gap to the eventual application of new findings in practice. Next, the reach and diversity of research collaborations (as identified through publication co-authorship) were studied to characterise the inter-disciplinary nature of heritage science and its connectedness to users. Findings showed substantial growth in international research collaborations over recent years, predominantly involving academic- and research-oriented institutions – although the engagement of heritage institutions has proportionally decreased. In addition, a worldwide survey of institutional planning and evaluation practices revealed a general reliance on processes driven by the interests of researchers – the systematic consideration of stakeholder opinion and evaluation of research outcomes being less common. Finally, a series of semi-structured interviews with senior heritage professionals explored their experience of collaborative research. The results identified key areas where strategic support is needed to promote user participation and enhance impact. These include training for research readiness, engagement, and impact for both researchers and users; better methods for needs and outcome assessment; affordable open access options and greater diversity of knowledge exchange opportunities. Finally, the need for ethical guidelines for responsible research, and greater emphasis on non-academic impact within research rating systems are discussed.     

Built-Heritage Multi-temporal Monitoring through Photogrammetry and 2D/3D Change Detection Algorithms

ABSTRACT

Cultural heritage assets are continuously exposed to risks and hazards. With the main aim to assess deterioration and improve conservation methods, the scientific community has proposed a variety of tools for the early identification of changes in heritage. Multidisciplinary approaches are common in heritage monitoring and conservation. This paper investigates the potential of change detection algorithms developed in remote sensing, and here applied at the monumental scale instead of the geo-spatial one. A monitoring methodology which integrates photogrammetry, 2D/3D change detection, and data interpretation is described and tested on the façade of the church of Stavros tou Missiricou (church of the Cross within the walls) in Nicosia, Cyprus.     

The inherent sharing of conservation decisions

Abstract

This paper provides an understanding of an under-explored aspect of the sharing of conservation decisions. In particular, it argues that conservation decisions are inherently shared in at least three senses. First, conservation is conceived as a field of shared values, principles, and decision-making methodology, and aspires to a universally shared ethic. This view is supported by the logical and ethical consistency of existing Codes of Ethics, and is made manifest with the aid of a conceptual model of what science is. Second, conservation decisions are conditioned by the identity of heritage entities. The values comprising the heritage identity of an entity transcend space and time boundaries; they are interrelated and interdependent and, as such, shared. Third, the benefits but also the harms stemming from conservation decisions and actions are distributed and shared among all people for whom the object of a conservation decision is heritage. As dictated by the do-no-harm principle, conservators have a duty to consider risks of such harms when making decisions.     

Cinnabar reviewed: characterization of the red pigment and its reactions

Abstract

In the majority of cases, the red color of cinnabar on objects of cultural heritage is well preserved, though turning black is often claimed and has been the subject of investigations. To evaluate conditions for the stability of the pigment and understand the reactions, in this paper the problem is approached from various viewpoints. First of all the natural form cinnabarite is compared with the artificially prepared pigment vermilion. This establishes a differentiation of types in terms of quality, depending on structural impurities. With regard to the pigment's reactions influencing the discoloration, the most commonly mentioned environmental factors, such as radiation or halogens, are evaluated. In relation to various usages, the pigment's structural stability is then viewed in connection with adjacent pigments, glues, and the substrate, which may lead to a brown or black coloration or even the release of mercury, whereas the color is preserved in most cases when used on lime or in ink and lacquer. Due to the materials’ properties, attention is drawn to the fact that discoloration to a brownish-black is not necessarily a sign of damage and harmful reaction products, but may indicate good preservation of the painted material, provided that the mercury can be bound in the substrate.     

Embodiment unbound: Moving beyond divisions in the understanding and practice of heritage conservation

Abstract

This contribution discusses how embodied heritage values operate within a context of heritage sites, and tangible and intangible embodiments of what is valued as heritage. This is partly intended to re-contextualize ideas of material and materiality that have recently undergone reconsideration in conservation and heritage discourse. The paper questions the claim that ‘Eastern’ and ‘Western’ philosophies of conservation are very different, and that they can be characterized as being concerned with intangible and tangible heritage, respectively. This is based on the assertion that influential preservation doctrines are as much a product of the context and practical situations as they are a product of different philosophies and cultures. Well-known examples from East and West are discussed to highlight the similarities, as opposed to the differences, in approaches. The article goes on to discuss the UNESCO definition of intangible heritage (2003), which conflates the intangible embodiment of values with the intangible values attributable to all heritage. As a way to contextualize this, the article considers embodiment of heritage values as a means to express both intangible and tangible heritage sites (since neither embodiment nor sites have to be physical). This is described by way of a simple, pre-existing communication model that moves from information source (which transmits the message) through the medium (the heritage site or object) to the audience (heritage user). These insights are intended to provide a balanced perspective that accommodates both the site and the embodied values in order to help make and justify conservation decisions.     

Differential thermal expansion as a cause of salt decay: literature review,experiments, and modelling of micro and macro effects on Ançã limestone

Salt decay is one of the harshest, most frequent, and more complex types of decay of porous materials in built heritage, including natural stones, ceramics, and mortars. In this article, we address the mechanism of thermal expansion, which is one of the least studied, yet most controversial, of those proposed over time to explain salt decay. We present a review of scientific literature on the topic, followed by a study of the effects of thermal expansion on a specific material, the well-known Ançã limestone. The study included experimental measurement of the linear thermal expansion coefficient of the Ançã, both in its natural state and with varying contents of sodium chloride, sodium sulphate, or sodium nitrate. The results show that this coefficient: (i) is significantly higher when the stone is contaminated with salt; and (ii) scales approximately with the amount of salt contained in the stone pores, regardless of the type of salt. Based on these results and on modelling of damage modes at the microscopic and macroscopic levels, respectively, we conclude that thermal expansion can cause powdering, disaggregation, or other types of decay consisting of internal loss of cohesion. However, it is not likely to cause exfoliation of salt-loaded layers.     

Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI® dosimetry

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air pollutants is less often measured or included in risk assessment. The MEMORI^® technology presented in this paper was developed as a tool for easy measurement and assessment of the general risk of degradation of heritage objects situated indoors due to indoor exposure to air pollutants. MEMORI dosimetry was performed in locations belonging to English Heritage and Tate (both located in London) and the National Archives of Norway in Oslo, to assess air quality. The related damage risk for collection objects and the protection offered by display and storage designs was assessed. A high level of acidic effect was observed inside a number of showcases, and a high level of oxidizing effect was observed in some room locations. Relatively simple mitigation measures, such as constructing tightly sealed showcases using low emitting materials, installing active carbon absorbing media inside a ‘microclimate’ frame, and using cardboard storage boxes for paper, significantly improved air quality. Overall, implementation of such measures is likely to improve the preservation of objects and reduce conservation costs.     

Plowing in Rocky Land: Organizational Culture, Managed Change, and Quality Improvement in Selected Romanian Post-Communist Libraries

Romanian libraries have had a rich heritage of collecting and preserving materials in the domains of national and foreign history, literature, art, and science. During the communist regime they served as propaganda tools for the government's Marxist ideology. In post-communist Romania, there is a desire among some librarians to promote change from a system of limited access to information to a more open system that focuses on quality improvement of library services, operations, and organization. In their efforts to overcome the communist legacy to libraries in their country, some Romanian librarians—with local resources and support from international agencies—are implementing western managerial styles and services. This case study reflects the results, assessments, and recommendations from a survey conducted at a workshop of selected Romanian librarians in August 1998. Considerations for the implementation of needed changes are also included.     

论图书馆学情报学研究中的模型方法

分析图书馆学情报学模型、模型方法的概念和图书馆学情报学模型的类型,论述图书馆学情报学模型研究的功能,总结构建图书馆学情报学模型的逻辑过程和方法论原则,概述模型方法在图书馆学情报学研究的应用领域,分析图书馆学情报学研究中模型方法应用的局限性与存在的问题。