Bacteria from black crusts on stone monuments can precipitate CaCO3 allowing the development of a new bio-consolidation protocol for ornamental stone

2020 ◽  
Vol 153 ◽  
pp. 105031
Author(s):  
M. Andreolli ◽  
S. Lampis ◽  
P. Bernardi ◽  
S. Calò ◽  
G. Vallini
Keyword(s):  
Stone Monuments ◽  
Ornamental Stone ◽  
Black Crusts

Resistance to Synthetic Seawater Aggression of Clay Ceramics Incorporated with an Ornamental Stone Residue

2014 ◽  
Vol 798-799 ◽  
pp. 269-274 ◽  
Author(s):  
Gustavo de Castro Xavier ◽  
Jonas Alexandre ◽  
Paulo César de Almeida Maia ◽  
Fernando Saboya Albuquerque ◽  
Leonardo Gonçalves Pedroti ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Standard Procedure ◽  
Degradation Process ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Synthetic Seawater ◽  
Internal Expansion ◽  
Ornamental Stone ◽  
Clay Ceramics ◽  
Chloride Salts

Clay ceramic materials exposed to a marine environment may be subjected to complete degradation due to the presence of chloride salts in the air. The exposition allows the chloride to penetrate in structural pores causing an internal expansion, which eventually split the ceramic apart. In open air, the solar radiation as well as the rain and wind contribute to accelerate the degradation process. In the present work the laboratory assisted degradation of clay ceramics incorporated with a granite residue from ornamental stone processing was evaluated by synthetic seawater aggression according to standard procedure. The amount of incorporated residues, up to 10 wt % and the ceramic firing temperature, up to 900°C, were variable conditions statistically analyzed by factorial planning. Degradation wetting-drying tests were conducted up to 6 months. The results showed that the linear shrinkage of the residue-free ceramics do not stabilize during the test period for any firing temperature. By contrast, the residue-incorporated ceramics tend to stabilize after 4 months. In addition, a decrease in water absorption and flexural strength was observed in same speciemens.

THE NEW RADIOCARBON DATASET FOR TRILITH MONUMENTS OF SOUTHEASTERN ARABIA

Radiocarbon ◽  
2020 ◽  
pp. 1-11
Author(s):  
R Garba ◽  
P Demján ◽  
I Svetlik ◽  
D Dreslerová
Keyword(s):  
Iron Age ◽  
Temporal Patterns ◽  
Temporal Analysis ◽  
Coastal Plains ◽  
Spatial And Temporal Patterns ◽  
Two Phase ◽  
Stone Monuments ◽  
South Central ◽  
Geographical Expansion ◽  
Spatio Temporal

ABSTRACT Triliths are megalithic monuments scattered across the coastal plains of southern and southeastern Arabia. They consist of aligned standing stones with a parallel row of large hearths and form a space, the meaning of which is undoubtedly significant but nonetheless still unknown. This paper presents a new radiocarbon (14C) dataset acquired during the two field seasons 2018–2019 of the TSMO (Trilith Stone Monuments of Oman) project which investigated the spatial and temporal patterns of the triliths. The excavation and sampling of trilith hearths across Oman yielded a dataset of 30 new 14C dates, extending the use of trilith monuments to as early as the Iron Age III period (600–300 BC). The earlier dates are linked to two-phase trilith sites in south-central Oman. The three 14C pairs collected from the two-phase trilith sites indicated gaps between the trilith construction phases from 35 to 475 years (2 σ). The preliminary spatio-temporal analysis shows the geographical expansion of populations using trilith monuments during the 5th to 1st century BC and a later pull back in the 1st and 2nd century AD. The new 14C dataset for trilith sites will help towards a better understanding of Iron Age communities in southeastern Arabia.

scholarly journals Protection of Stone Monuments Using a Brushing Treatment with Ammonium Oxalate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 379
Author(s):  
Domagoj Mudronja ◽  
Frederik Vanmeert ◽  
Stjepko Fazinic ◽  
Koen Janssens ◽  
Darko Tibljas ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Treatment Time ◽  
Protective Coatings ◽  
Ammonium Oxalate ◽  
Protective Layer ◽  
Thick Layer ◽  
Calcite Dissolution ◽  
X Ray ◽  
Stone Monuments ◽  
Surface Corrosion

Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-μ-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-μ-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5–15 µm on the less porous stone, while a 20–30 µm thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.

Comparing the bioremoval of black crusts on colored artistic lithotypes of the Cathedral of Florence with chemical and laser treatment

2011 ◽  
Vol 65 (6) ◽  
pp. 832-839 ◽  
Author(s):  
Eleonora Gioventù ◽  
Paola Franca Lorenzi ◽  
Federica Villa ◽  
Claudia Sorlini ◽  
Maria Rizzi ◽  
...  
Keyword(s):  
Laser Treatment ◽  
Black Crusts

scholarly journals On the observation of sun and stars made in some British stone circles

1908 ◽  
Vol 80 (538) ◽  
pp. 285-289 ◽  
Keyword(s):  
Special Class ◽  
Royal Society ◽  
Striking Difference ◽  
Stone Monuments ◽  
Made In

In previous communications to the Royal Society, I have shown that if we consider the sun’s declination at the quarter-days of the May year and at the solstices, and also the changes due to precession in the places of five or six of the more conspicuous stars visible, at any epoch, in these latitudes we are able to account for the alignments investigated in the stone monuments in Cornwall and Devon. The present paper deals with a special class of circles in Aberdeenshire in which the method of indicating alignments shows a striking difference. The Cornish method was that still set out in the instructions for the erection of the Gorsedd circle of the Welsh Eisteddfod, the sighting, or directing, stones were placed some distance outside the circle. In Aberdeenshire the method employed was to place a long, recumbent stone generally between two of the upright stones of the circle itself and to obtain the direction of the rising sun or star by sighting across the circle at right angles to the length of the recumbent stone.

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