共查询到20条相似文献，搜索用时 109 毫秒
1.
《文物保护研究》2013,58(2):99-110
AbstractThe deterioration of stone monuments in urban atmospheres mainly involves corrosion by acid solutions. Thus the characterization of the material is of great importance in the understanding of stone decay. In this work, samples were taken from the balcony of the Metropolitan Cathedral (Mexico City), from three different areas of the facade of the National Museum of Tepotzotlán (NW of Mexico City) and also, for comparison, new fresh stone from the quarries of Chiluca and Los Remedios. Mineralogical, petrographic, chemical and structural analyses were carried out on all the samples, and a relationship was established between the degree of decay and the stone characteristics, such as porosity, specific surface area and calcium content. The characterization of the type of stone also influences the selection of conservation treatments. 相似文献
2.
《文物保护研究》2013,58(4):190-192
AbstractThree methods of consolidating stone have been compared using Maastricht limestone as the substrate. They are: impregnation with polymer (Paraloid B 72) from solution; impregnation with a mixture of monomers followed by (a) γ-ray polymerization or (b) free-radical initiated thermal polymerization. The best results were obtained with the third method. 相似文献
3.
ABSTRACTAmong more than 600 decorated tumuli in Japan, we focused on Hinooka tumulus in Fukuoka prefecture. In order to preserve the stone chamber and paintings, a reinforced concrete shelter was built in 1964 on the stone chamber. From the preservation point of view, one of the main problems in the shelter is condensation on the ceiling especially in winter. In order to understand the mechanism of the formation of condensation in the shelter for Hinooka tumulus and to consider countermeasures to prevent it, the thermal environment inside the shelter was investigated by in situ measurements and computer simulations. Since the relative humidity inside the shelter is almost 100% throughout the year, it turned out that dew condensation tends to occur especially in winter when the temperature on the surface of the ceiling becomes low. The results obtained by computer simulation suggests that the amounts of condensation on the surface of the ceiling can be reduced if the thermal insulation of the roof is increased by adding materials which do not attract pests. Synthetic heat insulation material is one of the candidate materials for reducing condensate on the ceiling of the shelter for the Hinooka tumulus. 相似文献
4.
《文物保护研究》2013,58(2):105-112
AbstractThe degradation of coupled building stones has been simulated in a laboratory chamber using an artificial acid rain solution (‘wet’ deposition) with wet/dry cycling. The reaction of individual and coupled stones with the artificial acid rain was assessed from the pH, and confirmed by measurement of calcium ion content in the run-off. For the coupled stones, it is evident that there is a build up of damaging reaction products in the region of the lower stone closely adjacent to the upper stone. This behaviour is related to the increased time of wetness due to retained solution, containing calcium ions from runoff and anion species from the artificial acid rain solution, which allows locally enhanced reaction with the lower stone and subsequent development of salts. Where Leinster granite is the lower stone of the couple, calcium ions in the run-off from the upper stone, Portland limestone, accumulate in these regions, leading to the eventual development of gypsum in the near-surface regions of the granite, with extensive resultant degradation. The laboratory chamber allows rapid ranking of various stone combinations in the couple, and early insight into the degradation process which may ultimately assist in the development of conservation procedures. 相似文献
5.
《文物保护研究》2013,58(3):118-126
AbstractA series of corroded stone specimens from Salzburg monuments was examined by electron-probe microanalysis. The crusts arose from environmental effects, in the case of marble primarily from SO2. Deterioration phenomena can be correlated with stone surface features. 相似文献
6.
《文物保护研究》2013,58(1):53-58
AbstractThe presence of soluble salts in stone does not always lead to decay. Salt crystallization can be disruptive or cementing depending upon the pore structure of the stone and the crystallization pressure that develops within the pores. In this paper pore measurements on six types of stone and calculated pressure values are used to explain the decay morphology, and to show the correlation between the observed alteration processes and the crystallization pressure, which depends upon the pore-size distribution. 相似文献
7.
《文物保护研究》2013,58(3):102-107
AbstractBorobudur was constructed around 800 a.d. and abandoned in the 10th century. The history of its rediscovery in the early 19th century and subsequent restoration are discussed. An outline is given of various factors leading to the present preservation programme. The structure of the monument is described. Borobudur recalls the most elementary form of a stupa but is also a replica of the universe in Buddhist cosmology.The monument measuring 123 meters at its base is c. 31 meters high and has 504 statues and eleven series of bas-reliefs consisting of 1460 scenes; the total length of the sculptured surface is c. 3 km. The foot of the monument with the lowest series of reliefs was hidden by the ancient builders by a stone encasement. The significance and function of Borobudur are discussed from an historical point of view. 相似文献
8.
《文物保护研究》2013,58(4):228-238
AbstractA procedure for collection of decay rate data from stone samples exposed in actual environmental conditions is described. This provides precise weekly decay rate data. Data were collected for 16 consecutive months for 200-year-old weathered and freshly quarried Portland stone. Problems with the use of an acrylic sheet as a control were encountered and overcome. It is suggested that glass is a better control surface. Decay rates of new and old stone differed, with new stone typically being 60–70mg/m2/day. Close agreement was found between new stone replicates. Rates for old stones were much more variable and ranged from 90–270mg/m2/day. Differences were also found in the relative contributions of solution and particulate loss to total loss between the two stones. 相似文献
9.
《文物保护研究》2013,58(4):178-186
AbstractA radioactive tracer has been used to monitor the deposition of lime, that occurs when friable limestone is treated with a lime poultice and multiple applications of limewater. It has been shown that more than half the lime deposited is in the outer 2mm of the stone. Further into the stone, the amount deposited is so small that no consolidating effect can reasonably be expected. 相似文献
10.
11.
12.
《文物保护研究》2013,58(4):242-248
AbstractDilute solutions of epoxy resins have been used successfully in the past to consolidate deteriorated, porous stone. However, the appearance change (darkening, yellowing) on curing has proved to be a deterrent to the wider use of these materials by conservators. In the study reported here, it is shown that solvent washing to remove surface-deposited resin and exposure to sunlight are effective methods for restoring the original visual appearance of consolidated outdoor stone. 相似文献
13.
《文物保护研究》2013,58(3):163-170
AbstractThere is a need for a simple, rapid method which can be used with a minimum of equipment to evaluate whether microbial populations may pose a potential risk to the integrity of stone incorporated into buildings and works of art. Fluorescein diacetate (FDA) and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT) were compared for detection of microbial activity on stone, using both pure cultures of bacteria from stone and also natural stone samples. Both compounds could detect activity of bacteria and other microorganisms isolated from stone. INT-formazan was produced only by intact microorganisms whereas FDA was cleaved by extracellular enzymes as well. Use of FDA with stone samples was successful but INT required extended incubation times which gave little indication of in situ activity. A positive correlation was found between rapid cleavage of large amounts (> 15μg per gram stone) of FDA and production of INT-formazan after extended incubation periods. FDA was therefore found to be more appropriate as an indirect measure of metabolic activity of microbial populations on stone. The simplicity of the method makes it suitable for use by non-scientific personnel, with a minimum of scientific equipment, to identify stones at risk from active microbial populations. 相似文献
14.
《文物保护研究》2013,58(1):30-40
AbstractThe Kitora tumulus, which is thought to have been built around the late seventh to early eighth century, has beautiful mural paintings which were executed directly on a very thin layer of plaster in the stone chamber. When the paintings were found, the plaster was partly detached from the stone wall and the murals were therefore considered to be likely to fall off the wall with a casual touch or stimulation. Therefore, it was decided to detach the mural paintings and to store them flat and under controlled environmental conditions. This was initiated immediately after the excavation of the tumulus in 2004. However, fungal growth and biofilm development were observed within the stone chamber during the relocation work. In 2005, small holes containing black substances were observed on certain areas of the ceiling plaster, and following investigation an acetic acid bacterium, Gluconacetobacter sp., was isolated from the black substances. The bacterium was also isolated from the ceiling, floor, and east wall in the stone chamber in 2008 after the relocation of most of the paintings had been completed. These bacteria were shown to decompose calcium carbonate (CaCO3), one of the primary components of the plaster, and to produce organic acids such as acetic acid. Additionally, they were observed to decrease the pH of the culture media significantly in the presence of ethanol and glucose. This is the first example of the characterization of acetic acid bacteria isolated from decayed plaster paintings, and it is likely that microbes such as these bacteria have been involved in the deterioration of the plaster. Chemicals to treat microbes in the Kitora tumulus during the relocation work were selected on the basis of their antimicrobial efficacy, low potential to cause adverse effects on the paintings, and low level of toxicity to humans, depending on the condition of the plaster or stone in each area. However, some chemicals, especially ethanol, may act as a carbon source, which could encourage the growth of microbes and thereby the production of acids by the microbes when diluted to a low concentration or in a degraded state. Moreover, prior contamination by other microbial species in the form of a biofilm could also encourage the growth of the acetic acid bacteria by providing low-molecular-weight organic materials as a nutrient source. 相似文献
15.
16.
《文物保护研究》2013,58(4):183-193
AbstractA method for the detection of egg white in binding media by immunofluorescence was tested on laboratory samples. Although the fluorescence was weak, results were found to be reproducible. Tests were then carried out on a series of ancient paintings and polychromies dating from the twelfth century onwards. Some of these samples, including certain blues from Van Eyck's Mystic Lamb, gave a positive response for egg white. 相似文献
17.
Simona Raneri Jacopo Crezzini Simona Arrighi Francesco Boschin Ilaria Alfieri Germana Barone 《文物保护研究》2013,58(5):298-309
ABSTRACTThe surface texture of a stone represents a sensitive parameter in evaluating its conservation state. In monuments and sculptures, in fact, external agents continuously alter the appearance of stones, determining peculiar weathering patterns and modifying properties such as retention of water and particles, interaction with light, color, and finishing. The application of protective coatings also determines changes in surface appearance of a stone, usually evaluated and monitored by color change tests. Surface metrology methods offer the possibility to quantify these changes, evaluating the impact of external agents (natural, i.e. weathering, and artificially, i.e. protective coatings) on natural stones. In this research, we demonstrate the potential of surface areal measurements in describing the evolution of weathering processes and the effects of protective treatments on porous stone materials. The obtained results suggest that the extent of the modifications is related to the scale of observation (small- vs. large-scale undulations, i.e. roughness and waviness, respectively), with an overall increase of surface roughness as the weathering proceeds. Unexpectedly, coatings based on nanoparticle dispersions increase the topographic height parameters, due to the absence of a homogeneous film. 相似文献
18.
《文物保护研究》2013,58(1):49-58
AbstractBlack weathering layers on stone often contain iron. This is particularly true for the Turonian sandstones which were used extensively in architecture and sculpture in Saxony. In order to obtain more knowledge about the oxidic iron phases, samples were collected in the city of Dresden. Mineralogical and analytical characterization was provided for the black layers and the supporting stone. Material originating from Cotta and Posta stone was submitted to Mössbauer spectroscopy. After ample comparisons of Mössbauer parameters and evaluation of infrared spectra it was concluded that the predominant neogenic iron phase is not iron(III) oxide hydrite (ferrihydrite) Fe2O3·1·8H2O or jarosite KFe3(SO4)2(OH)6 or goethite α-FeO(OH) but a defectively ordered precursor of this last compound, characterized by different environments of the iron(III) ions. By the reducing action of organic matter, magnetite Fe4O4 is formed and this contains up to 45% of the iron present in a black layer. 相似文献
19.
《文物保护研究》2013,58(4):268-277
AbstractThe analysis of the surface ablation of the removal of lichens from stone by use of a free-running pulsed Er:YAG laser (erbium-doped yttrium, aluminium, garnet crystal) at a wavelength of 2.94 μm demonstrated the complete destruction of the lichen cell wall. In this paper these results are confirmed, and experiments are described which seek to determine the physical/chemical mechanism of the ablation process using pyrolysis gas chromatography–mass spectrometry (pyrolysis GC-MS), highperformance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR) and fluorescence microscopy. 相似文献
20.
《文物保护研究》2013,58(4):298-313
AbstractFive different methods for cleaning the limestone façades on what was originally the Workers Hospital in Madrid are analyzed in this paper. Due to the pollution in the surrounding air, just 20 years after a prior cleaning operation, sulfate crusts had developed on the entire stone surface of the building. The gypsum mortar used in the original masonry constituted an additional source of sulfur. Limestone is a traditional building material in Madrid and its surroundings. The petrography, mineralogy and petrophysical properties of the biomicrite, pelmicrite and biopelmicrite varieties of limestone identified in the hospital walls were determined. Analysis of a black layer on the stone surface showed that it consisted primarily of sulfate crusts. The cleaning methods tested were alkaline gels (sodium hydroxide and potassium hydroxide), pressurized hot water, glass bead blasting and latex peeling. The criteria for assessing the effectiveness and potential risks of the various cleaning systems included changes in the chromatic parameters of the stone, the formation of alteration products (i.e. salts) and modification of the stone surface. The stones cleaned with the three most effective methods, together with a rain-washed stone as a reference, were washed with water to generate an artificial runoff. The collected drain water was analyzed to determine the presence of any by-products from the cleaning process. The method found to be most effective and which caused the least alteration to the stone surface was glass bead blasting, particularly after adjustment of the bead size and pressure conditions used for the test. 相似文献