Rates of deterioration of Portland limestone in an urban environment

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.     

Epoxy resin-consolidated stone: appearance change on aging

Abstract

Dilute 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.     

Investigation of the Er:YAG Laser at 2.94 μm to Remove Lichens Growing on Stone

Abstract

The 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.     

A comparison of methods for the measurement of microbial activity on stone

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.     

Relative Humidity—Variation with Temperature in a Case Containing Wood

Abstract

Daylight and accelerated ageing tests on a series of clear epoxy resins are described and the results discussed in terms of their tendency to yellow on exposure to light. Some factors important in the yellowing process are described. A series of dyestuffs which disperse easily in epoxy resin to give transparent casts with good light-fastness is reported.     

THE CONSERVATION OF PYRITIC STONE ANTIQUITIES

Abstract

The occurrence and identification of ‘fossil disease’ in stone artifacts is described, together with details of techniques for the stabilization and consolidation of the specimens.     

Regulation

AMERICAN REGULATORY FEDERALISM & TELECOMMUNICATIONS INFRASTRUCTURE edited by Paul Teske (Hillsdale, NJ: Lawrence Erlbaum, 1995—$36.00, ISBN 0–8058–1615–1, 167 pp.)

CROSSROADS ON THE INFORMATION HIGHWAY: CONVERGENCE AND DIVERSITY IN COMMUNICATIONS TECHNOLOGIES (Institute for Information Studies, The Aspen Institute, Wye River Conference Centers, PO Box 222, Queenstown, MD 21658—$10.00, paper, ISBN 0–89843–164–6, 166 pp.)

MASS MEDIA LAW: CASES AND MATERIALS by Marc A. Franklin and David A. Anderson (Westbury, NY: Foundation Press, 1995—price not given, ISBN 1–56662–256–5, 802 pp.)

BROADCAST REGULATION: A REVIEW OF ‘94, A PREVIEW OF ‘95 (National Association of Broadcasters, 1771 N St. NW, Washington, DC 20036—$25 to BEA members; $65 to NAB members; $110 list price, paper, no ISBN given, 250 pp.)     

The Measurement of Film Thickness and of Solvent Action on Supported Films

Abstract

An efficient and simple method for the vacuum impregnation of stone is described, based on the formation of an airtight jacket around the object allowing a vacuum to be applied to the surface and acting as a wick for the consolidating material.     

THE USE OF THE AIRBRASIVE PROCESS FOR CLEANING ETHNOLOGICAL MATERIALS

Abstract

Ethnological specimens of many different materials can be dry cleaned mechanically by means of a grit-spraying unit. Plain and painted leather, corroded metal, beadwork, metallic embroidery, wood, ivory, bone, basketry, some paper, pottery, shell, some textiles and stone are items which can be cleaned with less disturbance to the surface than is often occasioned by the use of other methods. A specimen constructed of several materials may be cleaned by this one method rather than by several, thereby also avoiding the use of water, solvents or other chemicals. The powdered abrasives used are calcium magnesium carbonate, sodium bicarbonate, glass beads, and several grades of aluminium oxide. Silicone carbide powder is used occasionally for very hard corrosion products on metal.     

Characterization of stone from the Metropolitan Cathedral and from the facade of the National Museum at Tepotzotlan,Mexico

Abstract

The 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.     

An Ethnographic Study of Attitudes Influencing Faculty Collaboration in Library Instruction

SUMMARY

Numerous surveys over the years have found that faculty value librarians more for their reference work, often described as “service,” than for their contributions to teaching; that 55–85 percent of faculty report using no LI with their classes; and that faculty have various reasons for not using librarian-provided instruction. This study differs from its predecessors by focusing specifically upon faculty who use LI heavily with their courses and interviewing them about why they use LI and what they value about it. Understanding these faculty members' values regarding LI, as expressed in their own words, can assist librarians in promoting course-integrated instruction.     

An examination of the value of the re-forming technique in practice

Abstract

The varnishes of 166 paintings were examined, before and after re-forming, by means of mixtures of cyclohexane, toluene and acetone having systematically increasing solvent power. The examination proves that re-forming facilitates the solubility of aged traditional natural resin varnishes. 54% of the varnishes were removed, after re-forming, with toluene and even ‘milder’ solvents.     

Investigation of acetic acid bacteria isolated from the Kitora tumulus in Japan and their involvement in the deterioration of the plaster of the mural paintings

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.     

Creating Collaborative Workstations for Reference and Public Use in Academic Libraries

ABSTRACT

The current focus on libraries as place involves the collaborative needs of library users for features such as movable furniture, group work areas, and amenities such as coffee shops. Additional attention needs to focus on how the technology infrastructure can support collaborative work in academic libraries. The one-user-one-machine setup common in many academic libraries does not do this. A collaborative workstation that is inexpensive and readily assembled is described along with equipment needs and costs. The impact of such a collaborative workstation for both reference work and public use is discussed.     

German communication books

CONVERGENCE: THE JOURNAL OF RESEARCH INTO NEW MEDIA TECHNOLOGIES (John Libbey &; Co., 13 Smiths Yard, Summerley St., London SW 18 4HR, England—various rates ranging from $32 for individuals by surface mail to $90 for institutions by air mail, ISSN 1354–8565)

TELECOMMUNICATIONS RESEARCH RESOURCES: AN ANNOTATED GUIDE by James K. Bracken and Christopher H. Sterling (Mahwah, NJ: Lawrence Erlbaum, 1995—$36.00/17.50, ISBN 0–8058–1886–3 hard, 0–8058–1887–1 soft, 173 pp.)

PUBLIC ACCESS TO THE INTERNET edited by Brian Kahin and James Keller (Cambridge, MA: NIT Press, 1995—$40/20, ISBN 0–262–11207–8 hard, 0–262–61118‐X, 390 pp.)

COMPUTER PIONEERS by J.A.N. Lee (IEEE Computer Society Press, 10662 Las Vaqueros Circle, P.O. Box 3014, Los Alamitos, CA 90720–1264— $54.00, ISBN 0–8186–6357‐X hardcover, 0–8186–6356–1 microfiche, 816 pp.)

WIRELESS AND SATELLITE TELECOMMUNICATIONS: THE TECHNOLOGY, THE MARKET &; THE REGULATIONS by Joseph N. Pelton (Upper Saddle River, NJ: Prentice Hall PTR, 1995—price not given, ISBN 0–13–140493–8, 277 pp.)     

3. ELECTRONIC MEDIA

NARRATIVES AND SPACES: TECHNOLOGY AND THE CONSTRUCTION OF AMERICAN CULTURE by David E. Nye (New York: Columbia University Press, 1997—$45.00/17.50, ISBN 0–231–11196–7 hard, 0–231–11197–5 paper, 224 pp., index)

NEW MEDIA TECHNOLOGY: CULTURAL AND COMMERCIAL PERSPECTIVES by John V. Pavlik (Boston: Allyn and Bacon “Allyn &; Bacon Series in Mass Communication,”; 1998 [2d ed.]—$24.00, paper, ISBN 0–205–27093‐X, 400 pp., glossary, bibliography, index)

CULTURES OF INTERNET: VIRTUAL SPACES, REAL HISTORIES, LIVING BODIES edited by Rob Shields (London and Thousand Oaks, CA: Sage Publications, 1996—$69.95/22.95, ISBN 0–8039–7518‐X hard, 0–8039–7519–8 paper, 196 pp., index)

VISUAL CULTURE: AN INTRODUCTION by John A. Walker and Sarah Chaplin (Manchester, England: Manchester University Press / New York: St. Martin's Press, 1998—$79.95/24.95, ISBN 0–7190–5019–7 hard, 0–7190–5020–0 paper, 231 pp., index, appendix, black and white illustrations and photographs, summaries at end of each chapter)     

SOME ASPECTS OF THE CONSERVATION OF WORKS OF ART IN BUILDINGS OF NEW CONCRETE

Abstract

This paper deals with the materials used in conservation treatments in the first half of the twentieth century for the preservation and consolidation of wooden art objects from the Saxony region in Germany. The use of such materials must be seen as early attempts to find a conservation treatment for wood. The documentation of conservation treatments provides a reference to the application of oils and oil–resin mixtures. The results from the chemical analysis of samples of historic preservatives from the beginning to the middle of the twentieth century (so-called 'Puckelin') carried out by gas chromatography–mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) analysis confirm the use of tung oil as a drying oil, whereas the use of linseed oil cannot be excluded. Colophony and, probably, amber varnish were used as resinous constituents. There are indications that a conservation material dating from the second half of the twentieth century most likely contained rapeseed oil.     

Mineralogical-chemical Alteration and Origin of Ignimbritic Stones Used in the Old Cathedral of Nostra Signora di Castro (Sardinia,Italy)

ABSTRACT

The pyroclastic rocks belonging to the Late Eocene-Miocene volcanic activity that occurred in Sardinia between 38 and 15 Ma ago were widely used as construction materials in several Romanesque churches of the easternmost Logudoro area, as well as in large parts of the Sardinia territory. In this work, the ancient Cathedral of Nostra Signora di Castro (twelfth century) was taken as a representative case study. There is no historical or archaeological evidence of ancient quarries. Based on the geochemical, petrographic, and volcanological data on several samples from an extensive field area (approximately 150?km²), a geographical zoning of the volcanics has been recognised. In the Oschiri sector, there are three different sub-zones, which can be identified with different volcanic rocks: less fractionated rocks (Differentation Index ～70–78); intermediately fractionated rocks (D.I. ～76–79); and more fractionated rocks (D.I. ～77–82). To identify the origin of the ignimbrite rocks of the Church of Nostra Signora di Castro, two statistical methods were used: stepwise linear discriminant and canonical analysis. Moreover, to define the geochemical transformation processes induced by the alteration, a comparative study of concentrations of major and trace elements measured by XRF and SEM-EDX analyses on the surface portion and the innermost areas of the stone was made.     

National and international policies for preservation

Abstract

The aim of the study is to measure the effects of information resources and services of a regional information resources centre (NR CRI Library, Umudike), on the work of agricultural scientists within South Eastern Nigeria. The adequacy and relevance of resources and services were also examined.

One hundred and forty-one copies of a structured, self-administered questionnaire were sent to 140 scientists and one Head Librarian. Ninety-nine (70%) were retrieved and analysed. Data were also generated from intervies and a randomly selected sample, from documentary sources and observations. Analysis focused on library use, resources, services, effects of use on performance, relevance and adequacy of resources and services. Simple analytical tools such as graphs, charts and tables were used to elucidate library use, operations, benefits, effects of use on performance, relevance and adequacy of resources and services.

Results showed that research objective (20%) was the most common reason why scientists sought information and that information “effectively improved” the work of 73% of scientists. It also showed that among six other technical determinants that are essential for agricultural research, the importance attributed to the contribution of information to the success of research varied between groups of scientists. This trend was also observed in the amount of work achieved by scientists with the use information. The highest (20·4%) showed respondents who accepted that 31–40% of their research work was achieved with the use of information. The     

Telecommunications

SATELLITE COMMUNICATION SYSTEMS edited by B. G. Evans (London: The Institution of Electrical Engineers “Telecommunications Series 38,”; 1999 [3rd ed.]—$120.00, ISBN 0–85296–899‐X, 727 pp., photos, tables, charts, diagrams, appendices, index)

TELECOMMUNICATIONS DEPARTMENT MANAGEMENT by Robert A. Gable (Norwood, MA: Artech House, 1999—$79.00, ISBN 0–89006–650–7,398 pp., diagrams, acronyms, bibliography, index)

GLOBAL WIRELESS STANDARDS GUIDE (Telecommunications Industry Assn., 2500 Wilson Blvd., Suite 300, Arlington, VA 22201–3834—$14.95, paper, no ISBN number given, 58 pp.)

CONNECTIONS: SOCIAL AND CULTURAL STUDIES OF THE TELEPHONE IN AMERICAN LIFE by James E. Katz (New Brunswick, NJ: Transaction Publishers, 1999—$34.95, ISBN 1–56000–394–4,364 pp., tables, charts, notes, index)

MASTERS OF THE WIRED WORLD: CYBERSPACE SPEAKS OUT edited by Anne Leer (London: Financial Times/Pitman Publishing, 1999—price not given, ISBN 0–273–63559‐X, 419 pp., photos, diagrams, index)

DESKTOP ENCYCLOPEDIA OF THE INTERNET by Nathan ]. Muller (Norwood, MA: Artech House “Telecommunications Library,”; 1999—price not given, ISBN 0–89006–729–5, 558 pp., photos, diagrams, charts, tables, acronym list)

INTRODUCTION TO TELEPHONES AND TELEPHONE SYSTEMS by A. Michael Noll (Norwood, MA: Artech House, 1999 [3rd ed.]—price not given, ISBN 1–58053–000–1, 373 pp., photos, diagrams, glossary, bibliography, index)

NEW INTERNATIONAL CARRIERS: THE GUIDE TO INTERNATIONAL TELECOMMUNICATIONS CARRIERS ASIA‐PACIFIC EDITION, 1999 (1999—$595.00, paper, ISBN 1–88614247–3, 235 pp., maps, charts, tables, index); and

NEW INTERNATIONAL CARRIERS: THE GUIDE TO INTERNATIONAL TELECOMMUNICATIONS CARRIERS EUROPE EDITION, 1999 (1999—$595.00, paper, ISBN 1–886142–18–1, 377 pp., maps, charts, tables, index)

INFORMATION WARFARE: PRINCIPLES AND OPERATIONS by Edward Waltz (Norwood, MA: Artech House, 1999—price not given, ISBN 0–89006–511‐X, 397 pp., tables, diagrams, endnotes, index)