Conservation practices

A varnish is often appHed on top of the paint layers. A varnish serves two purposes as a protective coating and also for an optical effect that enriches the colors of the painting. A traditional varnish consists of a natural plant resin dissolved or fused in a Hquid for appHcation to the surface (see Resins, natural). There are two types of varnish resins hard ones, the most important of which is copal, and soft ones, notably dammar and mastic. The hard resins are fossil, and to convert these to a fluid state, they are fused in oil at high temperature. The soft resins dissolve in organic solvents, eg, turpentine. The natural resin varnishes discolor over time and also become less soluble, making removal in case of failure more difficult (see Paint and FINNISH removers). Thus the use of more stable synthetic resins, such as certain methacrylates and cycHc ketone resins, has become quite common, especially in conservation practice. 

Irrigation Erosion Control (Poljacrylamide), National Resources Conservation Service, Interim Conservation Practice Standard WNTC 201-4,1995. 

Extraction of Bertrandite. Bertrandite-containing tuff from the Spor Mountain deposits is wet milled to provide a thixotropic, pumpable slurry of below 840 p.m (—20 mesh) particles. This slurry is leached with sulfuric acid at temperatures near the boiling point. The resulting beryUium sulfate [13510-49-1] solution is separated from unreacted soflds by countercurrent decantation thickener operations. The solution contains 0.4—0.7 g/L Be, 4.7 g/L Al, 3—5 g/L Mg, and 1.5 g/L Fe, plus minor impurities including uranium [7440-61-1/, rare earths, zirconium [7440-67-7] titanium [7440-32-6] and zinc [7440-66-6]. Water conservation practices are essential in semiarid Utah, so the wash water introduced in the countercurrent decantation separation of beryUium solutions from soflds is utilized in the wet milling operation. 

Hence, the need for new perspectives has been called for in the study of the adoption and diffusion of sustainable agriculture, with focus on access to, and quality of information (Lovejoy and Napier 1986), the perception of innovations, and the institutional and economic factors related to adoption (Alonge and Martine 1995). Some studies have concluded that it is likely that the successful adoption of conservation practices would be influenced more by a farmers attitude and perception, than any other factor (Alonge and Martine 1995). 

The farmers are well aware of the erosion risk and they try to stabilize soils after failure by dewatering the sites and by conservation practices that include the use of... 

Poor soil-conservation practices in the early 1900s contributed to the loss of much topsoil to wind storms thick with dust. 

Although erosion is not serious in some cases at velocities as high as 10-15 ft/sec, conservative practice in the absence of specific knowledge limits velocities to 5-6 ft/sec. 

For conservative practice, these leakages may be taken as supplementary to those from Eq. (7.59). Other practices allow 5 Ib/hr for each agitator stuffing box of standard design special high vacuum mechanical seals with good maintenance can reduce this rate to 1-2 Ib/hr. 

Oreszczyn, T., Cassar, M. and Fernandez, K. (1994) Comparative study of air-conditioned and non air-conditioned museums. Preprints of the Contributions to the Ottawa Congress, Preventive Conservation-Practice, Theory and Research. The International Institute for Conservation of Historic and Artistic Works IIC, Ottawa, Canada, pp. 144—8. 

We must have an appreciation for the problems of our curator colleagues and work in collaboration with them. We hope they in turn will be concerned for and become knowledgeable in matters of preservation. It is not necessary for either curator or conservator to become a scientist, but understanding the concepts, methods, and language of science will help them both not only to work with scientists but also to know how to ask the right kind of questions or define with precision the particular problems they may wish them to investigate. The more precise the definition of the problem, the more likelihood there is that the questions will lead to answers that can be relevant to actual conservation practice. 

Celluloses are similar to other linear polymeric materials in that they can possess one-dimensional order within an individual chain as well as three-dimensional order within an aggregate of chains. Increments in the levels of order occur during the isolation of native celluloses and also as a result of exposure to conditions that promote molecular mobility, such as elevated temperatures and immersion in plasticizing fluids. These increments generally result in embrittlement of the cellulosic materials. Similar effects are expected to occur upon aging of cellulosic textiles and papers over extended periods, and may be accelerated by hydrolytic cleavage of cellulosic chains. The implications of these effects for conservation practices, both with respect to recovery of function as well as in the assessment of deterioration, are reviewed. 

Another possible use of this methodology, which is also highly desirable, is the monitoring of ordinary conservation practices, such as cleaning, to determine if the time left is affected by the proposed treatment. Further possible uses include assessing the appropriateness of those treatments such as consolidation and deacidification that have been designed to change the time left to determine if, and to what extent, it has been extended or shortened by the treatment. 

Other financial incentives include bonuses for conservative practice style, usually in conjunction with incentives for quality, access, and patient satisfaction. Still another mechanism is for physicians to share some of the financial risk for hospital care. 

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