Environmentally-induced stone decay: the cumulative effects of crystallization–hydration cycles on a Lincolnshire oopelsparite limestone     

Belinda J. Colston  David S. Watt  Helen L. Munro   《Journal of Cultural Heritage》2001,2(4)

An investigation has been undertaken at St Andrew’s church, Walpole St Andrew, Norfolk, to establish the underlying causes of the observed stone decay to the upper parts of the six stone piers. The stone decay was first recorded in the early 1930s. The salt-contaminated masonry within the church has been shown to undergo severe salt decay during the summer, with little damage occurring over the winter months. The south aisle piers have been shown to decay 2.5 times faster than the north aisle piers. Although crystallization–hydration cycles have been identified, the rate of decay is at its greatest when the cycling is relatively infrequent. This was not the expected trend. Furthermore, it has been shown that during extended periods where the ambient relative humidity is less than 75%, the rate of decay reaches a maximum. It is the length of this ‘drying’ period that apparently has the greatest influence on the rate of decay and could explain the significant difference in the rate of decay between the south and north aisle piers. The results have serious implications for passive conservation, where it is often recommended to lower the ambient relative humidity to well below the equilibrium relative humidity of the salt contaminant, to avoid crystallization–hydration cycles. Since, at the time of building, the church was situated on the coast, it is possible that the sodium chloride contamination occurred during the building process (1440–1520), particularly since the area was prone to sea-flooding at this time. Alternatively, the salt could have been applied as a treatment during the general restoration of 1897. Whatever the source of the salt, it seems likely that the ambient environment was changed by the insertion of a sealed floor in 1897, which could account for the onset of the salt decay.  相似文献   

Characterizing Literacy: A Study of Western and Indian Literacy Experiences     

David R. Olson 《Interchange》2005,36(3):344-345

  相似文献   

The universities, scientific research and the national interest in Latin America     

Vessuri HM 《Minerva》1986,24(1):1-38

  相似文献   

Measures of excellence: the search for the gold standard.     

V H Holtz 《Journal of the Medical Library Association》1986,74(4):305-314

Questions concerning some of the values we hold as librarians and the goals, standards, and other evaluation tools we derive from them are discussed in the context of the history of our profession and the present period of rapid change. The concepts of stable and changing paradigms and of "scientific communities" provide the foundation for consideration of how a changing conceptual framework can affect values and their application in the evaluation process. One of many possible scenarios for the future is briefly outlined to demonstrate how some traditional values may fare.  相似文献   

A commentary on the last illness of Sir William Osler     

Segall HN 《Osler Library newsletter》1985,(50):1-3

  相似文献   

Review of criteria used to measure library effectiveness     

E Evans  H Borko  P Ferguson 《Bulletin of the Medical Library Association》1972,60(1):102-110

This article reports the results of a survey of literature on measures of library effectiveness. This survey led to the formulation of six criterion concepts (accessibility, cost, user satisfaction, response time, cost/benefit ratio, and use). The advantages and disadvantages of each method of measurement are discussed. Several points which became clear during the analysis are discussed. First, there is a relative lack of concern with the rationale behind the evaluation process, although the results invariably lead to a confused interpretation when there is no clear understanding of the purpose of an evaluation. Second, the total library system is rarely considered; instead, each evaluation criterion is taken in isolation rather than as part of the whole. Third, the library's preservation function has not been considered at all.  相似文献   

Summary report of a study of academic medical library statistics     

V M Pings  E E Olson  R H Orr 《Bulletin of the Medical Library Association》1969,57(3):233-238

  相似文献   

The hospital library committee: its composition and tasks     

F Schiller  G H Merritt 《Bulletin of the Medical Library Association》1967,55(3):321-323

Since a sizeable hospital must have a library, it must have a library committee. Like all hospital committees, this one is to help maintain standards of medical care and to mediate between staff and administration. Unlike others, it clusters around one elected member (the chairman) and one employee (the librarian). A dynamic librarian can, and should, influence and inspire the committee's deliberations; and must be able to depend upon the support of the physician members of the committee.  相似文献   

Centralization vs. decentralization in medical school libraries     

Crawford H 《Bulletin of the Medical Library Association》1991,79(2):194

  相似文献   

The marcia C. Noyes award     

Pizer IH 《Bulletin of the Medical Library Association》1991,79(3):339

  相似文献