scholarly journals Effects of Water on Natural Stone in the Built Environment—A Review

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 459
Author(s):  
Carlos Alves ◽  
Carlos A. M. Figueiredo ◽  
Jorge Sanjurjo-Sánchez ◽  
Ana C. Hernández
Keyword(s):  
Built Environment ◽  
Salt Crystallization ◽  
Salt Weathering ◽  
Laboratory Studies ◽  
Physical Damage ◽  
Stone Conservation ◽  
Running Water ◽  
Freeze Thaw ◽  
Clastic Rocks ◽  
The Impact

The present work reviews studies with information on the effects of water by itself on stones of the built environment both to assess the impact of this substance and to discuss possible implications for conservation. The analysis concerns empirical results from previous publications dealing with the effects, on several rock types, of freeze–thaw, wetting, erosion by running water and substances resulting from the water–stone interaction. Laboratory studies have shown that water freezing can cause physical damage even in low porosity rocks. As far as we know, this is the first review that considers comparative laboratory studies of freeze–thaw and salt crystallization on the same rock specimens, and these point to lower erosive effects than salt weathering, as freeze–thaw can provoke catastrophic cracking. Wetting has shown strong damaging effects on some fine-grained clastic rocks. Erosive features have been reported for rain exposition and for some fountain settings albeit, in these field studies, it could be difficult to assess the contribution of pollutants transported by water (this assessment could have meaningful implications for stone conservation, especially in fountain settings). Water also interacts with stone constituents, namely sulfides and soluble salts, releasing substances that could impact those stones. Sulfides are a relatively frequent issue for slates and granites, and our observations suggest that for this last rock type, this issue is mostly associated with the presence of enclaves and, hence, avoiding the surface exposition of such enclaves could solve the problem.

scholarly journals NaCl-related weathering of stone: the importance of kinetics and salt mixtures in environmental risk assessment

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Sebastiaan Godts ◽  
Scott Allan Orr ◽  
Julie Desarnaud ◽  
Michael Steiger ◽  
Katrin Wilhelm ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Data Analysis ◽  
Salt Crystallization ◽  
Assessment Procedure ◽  
Climatic Data ◽  
Salt Weathering ◽  
Climate Data ◽  
Salt Mixture ◽  
Salt Mixtures ◽  
The Impact

AbstractSalt 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.

scholarly journals NaCl-Related Weathering of Stone: The Importance of Kinetics and Salt Mixtures in Environmental Risk Assessment

2020 ◽  
Author(s):  
Sebastiaan Godts ◽  
Scott Allan Orr ◽  
Julie Desarnaud ◽  
Michael Steiger ◽  
Katrin Wilhelm ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Data Analysis ◽  
Salt Crystallization ◽  
Assessment Procedure ◽  
Climatic Data ◽  
Salt Weathering ◽  
Climate Data ◽  
Salt Mixture ◽  
Salt Mixtures ◽  
The Impact

Abstract 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 were much 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 0.5 hour 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 and to illustrate a methodology with specific points of interest to quantify salt crystallization cycles in realistic environments as a risk assessment procedure that can be applied to climate data. The results are the basis for future work to improve the accuracy of salt risk assessment by including the kinetics of salt mixtures. This will improve the understanding of past and future salt weathering mechanisms and enable scientifically informed conservation strategies.

scholarly journals Freeze–Thaw and Salt Crystallization Durability of Silica Acid Ester Consolidated Porous Limestone from Hungary

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 824
Author(s):  
Zita Pápay ◽  
Nikoletta Rozgonyi-Boissinot ◽  
Ákos Török
Keyword(s):  
Tensile Strength ◽  
Water Saturation ◽  
Sodium Sulphate ◽  
Salt Crystallization ◽  
Strength Increase ◽  
Stone Conservation ◽  
Initial Strength ◽  
Freeze Thaw ◽  
Fine Grained

The durability of consolidated highly porous limestones was tested after salt and freeze–thaw cycles. Three porous limestone lithotypes that were commonly used in construction in the Central-European region during previous centuries were selected for the tests. Specimens of Miocene limestone were consolidated with four different types of ethyl silica-based consolidants (KSE 100, KSE 300, KSE 300 E, KSE 300 HV). After consolidation, the samples were exposed to freeze thaw cycles and salt crystallization tests. Water saturation under atmospherically pressure, capillary water absorption and splitting tensile strength were measured on treated and untreated samples to assess change attributed to consolidation in the open porosity and mechanical parameters. The increase in the tensile strength of the medium-grained samples was higher than that of the consolidated fine-grained lithotypes. The effect of consolidation treatment was very different in terms of pore-size distribution as obtained by Mercury intrusion porosimetry (MIP). Untreated and consolidated samples were subjected to 10 cycles of sodium sulphate crystallization (EN 12370) and 10 freeze–thaw cycles (EN 12371) tests. Experiments concluded that in addition to the initial strength increase after the conservation, the modified pore structure is the crucial factor to evaluate the long-term efficiency of stone conservation.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

The Impact of Zoning and Built Environment Characteristics on Transit, Biking, and Walking

2019 ◽  
Vol 11 (1) ◽  
pp. 108-129
Author(s):  
Andrew G. Mueller ◽  
Daniel J. Trujillo
Keyword(s):  
Land Use ◽  
Built Environment ◽  
Discrete Choice ◽  
Travel Behavior ◽  
Choice Model ◽  
Mode Choice ◽  
Land Use Regulation ◽  
Policy Action ◽  
Development Goals ◽  
The Impact

This study furthers existing research on the link between the built environment and travel behavior, particularly mode choice (auto, transit, biking, walking). While researchers have studied built environment characteristics and their impact on mode choice, none have attempted to measure the impact of zoning on travel behavior. By testing the impact of land use regulation in the form of zoning restrictions on travel behavior, this study expands the literature by incorporating an additional variable that can be changed through public policy action and may help cities promote sustainable real estate development goals. Using a unique, high-resolution travel survey dataset from Denver, Colorado, we develop a multinomial discrete choice model that addresses unobserved travel preferences by incorporating sociodemographic, built environment, and land use restriction variables. The results suggest that zoning can be tailored by cities to encourage reductions in auto usage, furthering sustainability goals in transportation.

scholarly journals KUALITAS AIR SUNGAI DI KAWASAN WISATA PANTAI PETITENGET, KEROBOKAN KABUPATEN BADUNG BALI

2018 ◽  
Vol 12 (2) ◽  
pp. 226
Author(s):  
Wayan Budiarsa Suyasa ◽  
Sri Kunti Pancadewi G. A ◽  
Iryanti E. Suprihatin ◽  
Dwi Adi Suastuti G. A.
Keyword(s):  
Water Quality ◽  
Structural Changes ◽  
Pollution Index ◽  
Basic Structure ◽  
Physical Damage ◽  
E Coli ◽  
Pollutant Source ◽  
Quality Category ◽  
Index Value ◽  
The Impact

In order to maintain the environmental carrying capacity of coastal tourism, this research was conducted to determine the condition of river water environmental pollution in the Petitenget beach area and pollutant source activities. Determination of water quality is carried out by analyzing the water quality taken at several sampling points in the four rivers that lead to the Petitenget beach. Determined the pollution index value (IP) of the physical chemical and biological pollution parameters. The results showed that the four rivers that flow into the Petitenget Beach area had been contaminated with indications of pH, BOD, COD, ammonia, Coliform and E. coli which exceeded water quality category III class quality (PerGub Bali No 16 Year 2016). The four rivers are included in the criteria of severe contamination. The four rivers have experienced physical damage or structural changes that have very high discharge fluctuations both in quantity and quality. Slimy basic structure, smelly and slum aesthetic waters. While the indication of the impact of pollution is waste water which is directly discharged into the river from hotels, restaurants, homestays, commercial centers and settlements.

Stock Market Volatility and Terrorism: New Evidence from the Markov Switching Model

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Faheem Aslam ◽  
Hyoung-Goo Kang ◽  
Khurrum Shahzad Mughal ◽  
Tahir Mumtaz Awan ◽  
Yasir Tariq Mohmand
Keyword(s):  
Stock Market ◽  
Significant Risk ◽  
Market Volatility ◽  
Terrorist Attacks ◽  
Stock Market Volatility ◽  
Markov Switching Model ◽  
Physical Damage ◽  
Stock Market Returns ◽  
Switching Model ◽  
The Impact

AbstractTerrorism in Pakistan poses a significant risk towards the lives of people by violent destruction and physical damage. In addition to human loss, such catastrophic activities also affect the financial markets. The purpose of this study is to examine the impact of terrorism on the volatility of the Pakistan stock market. The financial impact of 339 terrorist attacks for a period of 18 years (2000–2018) is estimated w.r.t. target type, days of the week, and surprise factor. Three important macroeconomic variables namely exchange rate, gold, and oil were also considered. The findings of the EGARCH (1, 1) model revealed that the terrorist attacks targeting the security forces and commercial facilities significantly increased the stock market volatility. The significant impact of terrorist attacks on Monday, Tuesday, and Thursday confirms the overreaction of investors to terrorist news. Furthermore, the results confirmed the negative linkage between the surprise factor and stock market returns. The findings of this study have significant implications for investors and policymakers.

Using Deep Learning to Understand Travel Demands in Different Urban Districts

2021 ◽  
pp. 036119812199458
Author(s):  
Shunhua Bai ◽  
Junfeng Jiao
Keyword(s):  
Built Environment ◽  
Travel Behavior ◽  
Prediction Accuracy ◽  
Travel Demand ◽  
Short Term Memory ◽  
Future Research ◽  
Demand Forecast ◽  
Time And Space ◽  
The University ◽  
The Impact

Travel demand forecast plays an important role in transportation planning. Classic models often predict people’s travel behavior based on the physical built environment in a linear fashion. Many scholars have tried to understand built environments’ predictive power on people’s travel behavior using big-data methods. However, few empirical studies have discussed how the impact might vary across time and space. To fill this research gap, this study used 2019 anonymous smartphone GPS data and built a long short-term memory (LSTM) recurrent neural network (RNN) to predict the daily travel demand to six destinations in Austin, Texas: downtown, the university, the airport, an inner-ring point-of-interest (POI) cluster, a suburban POI cluster, and an urban-fringe POI cluster. By comparing the prediction results, we found that: the model underestimated the traffic surge for the university in the fall semester and overestimated the demand for downtown on non-working days; the prediction accuracy for POI clusters was negatively related to their adjacency to downtown; and different POI clusters had cases of under- or overestimation on different occasions. This study reveals that the impact of destination attributes on people’s travel demand can vary across time and space because of their heterogeneous nature. Future research on travel behavior and built environment modeling should incorporate the temporal inconsistency to achieve better prediction accuracy.

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