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1.
《文物保护研究》2013,58(4):228-238
Abstract

A 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   

2.
《文物保护研究》2013,58(4):295-306
Abstract

A characterization method was designed to improve understanding of ancient mortars used in the land walls of Istanbul, Turkey. The mortars had hydraulic properties where slaked lime was the binder and crushed brick was the aggregate. For characterization purposes simple chemical and petrographic analyses may be sufficient. However, further scientific research based on instrumental analysis is needed for an understanding of ancient lime technologies, provenance of the materials and deterioration processes. Besides simple chemical and petrographic analysis, this paper describes the differential thermal analysis (DTA), inductively coupled plasma analysis (ICP), X-ray diffraction analysis (XRD), scanning electron microscope–energy dispersive X-ray analysis (SEM-EDX) and mercury intrusion tests that were conducted to evaluate the binders and aggregates of the samples. Their physical and mechanical properties were also determined, and salt decay is discussed. It was seen that limestone chips and river sand were used as aggregates, in addition to crushed brick. The brick dust served as an artificial pozzolanic additive. Salt decay originated from sea spray and air pollution.  相似文献   

3.
《文物保护研究》2013,58(1):53-58
Abstract

The 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   

4.
《文物保护研究》2013,58(3):163-170
Abstract

There 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   

5.
《文物保护研究》2013,58(1):30-40
Abstract

The 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   

6.
《文物保护研究》2013,58(1):49-58
Abstract

Black 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   

7.
《文物保护研究》2013,58(1):179-183
Abstract

This paper deals with the approach to the conservation of a Spanish-style saddle and anquera (rump cover) from Mexico City and Puebla, Mexico, respectively. The objects were originally bought by an English explorer for a journey and are described in his book. The saddle and anquera are made from vegetable-tanned cowhide with punched and embroidered decoration and metal fittings. The condition, of the leather was assessed scientifically. It exhibits a number of conservation problems, notably surface deterioration and detachment of several sections due to acid attack. Previous conservation treatments have caused the leather to become overstuffed with dressing, resulting in a weakening of the substrate. The conservation ofthe saddle will involve four main stages: removal of excess dressing, stabilization of the leather, consolidation of the friable surface and repair of torn and broken areas. The suitability of various stabilizing agents, consolidants and methods of application was evaluated using mechanical tests alone and accelerated aging and mechanical tests. Naturall y aged and degraded leather was used as an experimental substrate. The results were used to formulate the approach to the conservation of the saddle and anquera.  相似文献   

8.

Brasil em tempo de TV / BRAZIL IN THE ERA OF TV by Eugênio Bucci (São Paulo, Brazil: Boitempo Editorial, 1996—price not available, ISBN 85–85934–08–5, 183 pp.)

Medios de comunicación y democracia en El Salvador / COMMUNICATION MEDIA AND DEMOCRACY IN EL SALVADOR edited by Ricardo Bracamonte and Stefan Roggenbuck (San Salvador: Konrad Adenauer Foundation and Universidad Centroamericana, 1996—price and ISBN not available, 127 pp., bibliography)

Los procesos electorates en los medios de comunicación: Guía para el análysis de contenido electoral en Mexico / THE ELECTORAL PROCESS IN MEDIATED COMMUNICATION: A GUIDE FOR ELECTORAL CONTENT ANALYSIS IN MEXICO by Miguel Acosta Valverde and Luz Paula Parra Rosales (Mexico City: Academia Mexicana de Derechos Humanos, A.C. and Universidad Iberoamericana, A.C., 1995—no price available, ISBN 968–859–187–4, 270 pp., tables, charts, glossary, bibliography)

Al rescate de los medios: Desafío democrático para los comunicadores / RESCUING THE MEDIA: THE DEMOCRATIC CHALLENGE FOR COMMUNICATORS by Guillermo Orozco Gómez (Mexico City: Fundación Manuel Buendía and Universidad Iberoamericana, 1994—ISBN 968–6348–10–7, 160 pp., notes, bibliographies)

La industria de la telenovela: La productión de fictión en América latina / THE SOAP OPERA INDUSTRY: THE PRODUCTION OF FICTION IN LATIN AMERICA by Nora Maziotti (Buenos Aires: Editorial Paidós, 1996—price not available, ISBN 950–12–2707–3, 177 pp., notes bibliography)  相似文献   

9.
《文物保护研究》2013,58(3):171-176
Abstract

The weathering of stone monuments results in the leaching of calcite, with a consequent increase in porosity and decrease in integrity. A new method of consolidation uses organic matrix macromolecules extracted from Mytilus californianus shells to induce the precipitation of calcium carbonate within the pores of the stone. The procedure has been tested in the laboratory on samples of bioclastic limestone and dolostone, by measuring changes in total porosity, amount of water absorbed and superficial cohesion. The results appear to confirm the success of the treatment.  相似文献   

10.
ABSTRACT

Boundary walls are neglected but important parts of historic urban environments, and they are often prone to serious deterioration. Understanding moisture and salt dynamics within boundary walls can help infer the causes and dynamics of deterioration. This investigation investigates the patterns of moisture, salt, and deterioration on a 300 year old limestone boundary wall in Worcester College, Oxford. Multiple methods to assess moisture and salts within and across the wall (electrical resistivity tomography, handheld resistivity-based moisture meter, paper pulp poultices, scanning electron microscopy, inductively coupled plasma optical emission spectrometry, and ion chromatography of small scale sampling of deteriorated limestone) were used in conjunction with decay mapping of both sides of the wall. The salt weathering strongly correlates with severely weathered zones at the wall and salts, mainly sulfates, seem to be the main agent of decay processes. The combined results demonstrate that the environmental influences driving stone decay can differ on a very small scale even at a comparatively simple structure like a boundary wall, and that repairs can have adverse effects if the patterns of salt and moisture dynamics are not sufficiently known.  相似文献   

11.
ABSTRACT

Preventive conservation plans must include the collaboration of all the different departments within an institution to be able to diagnose the situation, provide proper maintenance, and allocate a budget. Preventive conservation entails understanding the collection’s needs, organizational culture, institutional priorities, and risk factors. Beyond the intervention of objects, the conservator is the creator of guidelines and the implementer of solutions. In this paper, need-based approaches are provided showcasing how tailor-built preventive conservation plans became merged into the backbone of everyday activities. In the Louis C. Morton Auction House in Mexico City, diagnosis tools were adapted, redefining conservation terms within a business-oriented model to guarantee success. In the National Museum of Art in Mexico, the sustainable preservation plan categorized actions within their realization capability. Tasks were allocated to different departments and suppliers; outsourcing, not the responsibility, but the commitment of continuity with service providers via contracts. At the Israel Museum in Jerusalem, the complex conservation projects have focused on high standard continuity. Motivating people to participate in the steady innovation, an encyclopaedic museum must have not only to conserve its collections, but also to serve as an international example.  相似文献   

12.
《文物保护研究》2013,58(3):118-126
Abstract

A 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   

13.
Ralph M. Jennings and Pamela Richard's How to Protect Your Rights in Television and Radio (Office of Communication, United Church of Christ, 289 Park Ave. South, New York 10010—price not given, paper)

Ted C. Smythe and George A. Mastroianni's Issues in Broadcasting: Radio, Television, and Cable (Palo Alto, Calif.: Mayfield Publishing Co., 1975—price not given but around $7.00 we learned from editors, paper)

James D. Secrest's Electronic Industries Association: The First 50 Years (Washington: EIA, 1974—price not given)

Ann M. Velia's KOB: Goddard's Magic Mast, Fifty Years of Pioneer Broadcasting (Las Cruces, N.M.: New Mexico State University Press, 1972—$6.95)

Harold Niven's Broadcast Education 1975: 14th Report (Washington: National Association of Broadcasters, 1975—$5.00, paper)

Broadcast Programming and Production (bimonthly/$7.00 per year, with first three issues free on request)

Joel L. Efrein, Cablecasting Production Handbook (Blue Ridge Summit, Pa.: TAB Books, 1975—$12.95)

NCTA is Over the Cable (Washington: National Cable Television Association, 1975—free on request, paper)

Community Antenna Television Journal (4209 N.W. 23rd St., Suite 106, Oklahoma City 73107)  相似文献   

14.
《文物保护研究》2013,58(2):105-112
Abstract

The 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   

15.
《文物保护研究》2012,57(1):59-64
ABSTRACT

We analyzed 53 historical textile samples from a collection of caftans and brocades dating between the sixteenth and nineteenth century in the Topkapi Palace Museum (TPM) by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Data were collected on the type, dimensions, elemental composition, and level of corrosion. The technique is presented in this work as an efficient and micro-destructive tool for the characterization of the structure of historical metal threads. SEM-EDX analysis for different energies was performed on a selection of gold and silver threads belonging to the historical textiles. The results were interpreted via laboratory prepared samples of gilt Ag and sulfur reacted Ag at different thicknesses for Au and Ag2S layers respectively. A series of Au–Ag alloys for different Au/Ag ratios were prepared for comparative analysis. The threads were made of metal strips wound around a silk core. Metal wires and flat strips were also used. The use of differential energies allowed for differentiating strips and wires made of homogeneous silver and gold alloys from the ones coated with a thin gold layer. Analysis of EDX data revealed that the Au film thickness was very thin (10–60?nm). Formation of Ag2S layers over the thin Au film as thick as 1.5?µm was taking place. Formation of thinner Ag2S layers over non-gilt Ag suggested different reaction mechanisms for gilt and non-gilt cases.  相似文献   

16.
ABSTRACT

Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol–gel, Ca(OH)2, and SiO2 nanoparticles. These were subjected to marine aerosol accelerated aging cycles and studied by several non-destructive tests and techniques to assess the stability of the products. Results show that weathering caused by salt crystallization is not inhibited but it is slowed down due to the enhancement of superficial mechanical properties (surface cohesion and micro-hardness) achieved after one month of treatments application. A high or low relative humidity of the consolidation environment significantly affects the final mechanical and aesthetical physical properties and therefore conditions the durability of the treated substrates, even producing higher damage than observed in the blank specimens, depending on the product.  相似文献   

17.
Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.  相似文献   

18.
《文物保护研究》2013,58(4):282-288
Abstract

A protocol for the characterization of proteins in paint media by immunofluorescent labelled antibodies is proposed. The main difficulties of the technique and their possible solutions are discussed. Positive results on egg white, in model samples, are reported.  相似文献   

19.
《文物保护研究》2013,58(1):130-132
Abstract

Original protective renderings have been the focus of numerous studies in recent years. Relevant literature, archival research and archaeological findings reveal that a number of mortar mixes or liquid substances were brushed on to protect and colour-unify the exterior ashlar-stone of many historic buildings. These coatings were of two types: common mortars, particularly improved with organic additives, and water-resistant filmforming substances. Economic cost, local supply, traditional practices and technological development are vital to an understanding of regional preferences for one mortar mix or material over another. The Cathedral of Leon is a mediaeval gothic temple from the thirteenth century, profusely remodelled throughout its history. In the sixteenth century, a new design of the courtyard partially enclosed a fifteenth-century exterior wall. Samples from the enclosed and exposed parts of this wall were examined. Analytical research suggests that the stone surface of this element received a treatment based on gypsum with organic additives. These organic products were fatty materials of the lipid type (tallow or lard) which reacted to form an insoluble, hydrophobic soap, at the same time providing the stone with its yellowish colour. The exceptional amount oflime registered in samples from the enclosed section has been considered a component of this surface treatment.  相似文献   

20.
《文物保护研究》2013,58(4):190-192
Abstract

Three 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   

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