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Salt related weathering of stones has been attributed to pressures exerted by repeated cycles of crystallization within pores. Relative Humidity (RH) is a key driver for dissolution and crystallization processes. Despite the prevalence of salt mixtures in natural environments, most experimental work has focused on single salts. Thus, the identification of salt mixture composition and their behavior is necessary to understand weathering. Thermodynamic calculations are used to analyze several thousand realistic salt mixtures found in weathered stone. We identify two common mixture types and their behavior. From at least 85 salt species theoretically present, 14 common salts are identified that occur most frequently and their critical RH points are discussed. These findings have wide-reaching implications for understanding salt weathering processes and informing the design of experimental stone weathering research.

Damage to porous materials in heritage buildings caused by salt mixture crystallization is driven by the surrounding environmental conditions. To understand the crystallization behavior of a mixed salt solution as a function of changing climatic conditions (i.e., relative humidity and temperature), excluding factors such as the internal pore structure, the thermodynamic model ECOS/RUNSALT is the only freeware available that requires simple input and includes the most relevant ions for heritage buildings and solids. We suggest the use of specific terminology and describe how to use the model and how to interpret the output, with emphasis on key limitations for which solutions are provided. When used correctly, the model output can be trusted, specifically when it is used to inform preventive conservation (e.g., environmental conditions in which salt crystallization cycles should not occur). However, salt mixture kinetics and the internal pore structure remain crucial parameters that are not considered in the model. These aspects need further attention to develop a better understanding and correctly model salt damage in relation to climatic changes.

Understanding salt mixtures in the built environment is crucial to evaluate damage phenomena. This contribution presents charge balance calculations applied to a dataset of 11412 samples taken from 338 sites, building materials showing signs of salt deterioration. Each sample includes ion concentrations of Na+, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42− adjusted to reach charge balance for data evaluation. The calculation procedure follows two distinct pathways: i) an equal adjustment of all ions, ii) adjustments to the cations in sequence related to the solubility of the theoretical solids. The procedure applied to the dataset illustrates the quantification of salt mixture compositions and highlights the extent of adjustments applied in relation to the sample mass to aid interpretation. The data analysis allows the identification of theoretical carbonates that could influence the mixture behavior. Applying the charge balance calculations to the dataset validated common ions found in the built environment and the identification of three typical mixture compositions. Additionally, the data can be used as direct input for thermodynamic modeling.

Multi-label Text Classification (MLTC) is the task of categorizing documents into one or more topics. Considering the large volumes of data and varying domains of such tasks, fully supervised learning requires manually fully annotated datasets which is costly and time-consuming. In this paper, we propose BERT-Flow-VAE (BFV), a Weakly-Supervised Multi-Label Text Classification (WSMLTC) model that reduces the need for full supervision. This new model (1) produces BERT sentence embeddings and calibrates them using a flow model, (2) generates an initial topic-document matrix by averaging results of a seeded sparse topic model and a textual entailment model which only require surface name of topics and 4-6 seed words per topic, and (3) adopts a VAE framework to reconstruct the embeddings under the guidance of the topic-document matrix. Finally, (4) it uses the means produced by the encoder model in the VAE architecture as predictions for MLTC. Experimental results on 6 multi-label datasets show that BFV can substantially outperform other baseline WSMLTC models in key metrics and achieve approximately 84% performance of a fully-supervised model., Comment: 8 pages, 4 figures

Collaboration between the two Joint Programming Initiatives “Cultural Heritage and Global Change” (JPI CH), and “Connecting Climate Knowledge for Europe” (JPI Climate) began in 2019 and led to the organisation of a joint workshop a year later. Following the recommendations in the workshop report, an expert working group was set up to scope research gaps and opportunities at the interface of cultural heritage and climate change, culminating in the publication of this White Paper. This strategic document is expected to support the two JPIs to generate policy-relevant research outcomes.

Climate change poses a threat to heritage globally. Decolonial approaches to climate change–heritage research and practice can begin to address systemic inequities, recognize the breadth of heritage and strengthen adaptation action globally., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Architecture and the Built Environment, History, Form & Aesthetics

Salt weathering is one of the most important causes of deterioration in the built environment. Two crucial aspects need further investigation to understand the processes and find suitable measures: the impact of different climatic environments and the properties of salt mixture crystallization. We demonstrate the importance of kinetics in quantifying crystallization and dissolution cycles by combining droplet and capillary laboratory experiments with climate data analysis. The results proved that dissolution times for pure NaCl are typically slower than crystallization, while thermodynamic modelling showed a lower RHeq of NaCl (65.5%) in a salt mixture (commonly found in the built heritage) compared to its RHeq as a single salt (75.5%). Following the results, a minimum time of 30 min is considered for dissolution and the two main RHeq thresholds could be applied to climate data analysis. The predicted number of dissolution/crystallization cycles was significantly dependent on the measurement frequency (or equivalent averaging period) of the climatic data. An analysis of corresponding rural and urban climate demonstrated the impact of spatial phenomena (such as the urban heat island) on the predicted frequency cycles. The findings are fundamental to improve appropriate timescale windows that can be applied to climate data and to illustrate a methodology to quantify salt crystallization cycles in realistic environments as a risk assessment procedure. The results are the basis for future work to improve the accuracy of salt risk assessment by including the kinetics of salt mixtures. [Figure not available: see fulltext.]

Research focusing on climate change and cultural heritage informs heritage management and policy. Fatorić and Seekamp assessed this field up to 2015, highlighting the need for periodic reassessment of the field given the observed growth and research that documents how cultural heritage contributes to climate change mitigation and adaptation. Five years on, this systematic review reflects on the state of the art by evaluating 165 publications (2016–2020) about cultural heritage and climate change. We find the field continues to grow, and remains rich in disciplinary and methodological diversity, but predominantly represents research in and about Europe. The number of publications about integrating cultural heritage into adaptation and mitigation are increasing but remain relatively few compared to those about physical impacts on individual buildings or sites. The impact of climate change on intangible heritage has rarely been the sole focus of recent research. Although researchers are increasingly situating their research in a wider context of opportunities and barriers, vague timescales, and unspecific references to changes in the natural environment are additional limitations. This review also identified a lack of international collaboration, highlighting the urgent need for global cooperation and knowledge exchange on climate change and cultural heritage., History & Complexity

Research focusing on climate change and cultural heritage informs heritage management and policy. Fatorić and Seekamp assessed this field up to 2015, highlighting the need for periodic reassessment of the field given the observed growth and research that documents how cultural heritage contributes to climate change mitigation and adaptation. Five years on, this systematic review reflects on the state of the art by evaluating 165 publications (2016–2020) about cultural heritage and climate change. We find the field continues to grow, and remains rich in disciplinary and methodological diversity, but predominantly represents research in and about Europe. The number of publications about integrating cultural heritage into adaptation and mitigation are increasing but remain relatively few compared to those about physical impacts on individual buildings or sites. The impact of climate change on intangible heritage has rarely been the sole focus of recent research. Although researchers are increasingly situating their research in a wider context of opportunities and barriers, vague timescales, and unspecific references to changes in the natural environment are additional limitations. This review also identified a lack of international collaboration, highlighting the urgent need for global cooperation and knowledge exchange on climate change and cultural heritage., History, Form & Aesthetics