Burying test

Meaney MJ (2001) Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations. Annu Rev Neurosci 24 1161-1192 Menard J, Treit D (1996) Lateral and medial septal lesions reduce anxiety in the plus-maze and probe-burying tests. Physiol Behav 60 845-853 Menzaghi F, Howard RL, Heinrichs SC, Vale W, Rivier J, Koob GF (1994) Characterization of a novel and potent corticotropin-releasing factor antagonist in rats. J Pharmacol Exp Ther 269 564-572... 

Test pipe for artificial reference (bO.Smm FBH whose burying... 

Tank installations with underground storage tanks and station piping should, if possible, be provided with conventional cathodic protection [3]. This is sometimes not possible because electrical separation cannot be achieved between the protected installation and other parts of the plant (see Section 11.4). The necessity for cathodic protection can be tested as in Ref. 13. In tank farms, a distinction should be made between coated, buried storage tanks and aboveground, flat-bottomed tanks in which the base contacts the soil. 

Cathodic protection cannot work with prestressed concrete structures that have electrically insulated, coated pipes. There is positive experience in the case of a direct connection without coated pipes this is protection of buried prestressed concrete pipelines by zinc anodes [38], Stability against H-induced stress corrosion in high-strength steels with impressed current has to be tested (see Section 2.3.4). 

All-plastic nonconductive pipe such as polyolefin is not recommended for handling nonconductive or semiconductive liquids except where it can be shown that the advantages outweigh any risks associated with external static ignition or leakage via pinholes, or where tests have demonstrated that the phenomena will not occur. Burying an all-plastic pipe prevents external... 

The slow rate of hydration for buried surfaces is desirable from a service point of view, but makes the study and evaluation of the durability of surface treatments difficult unless wedge tests (ASTM D3762) or similar tests are used to accelerate the degradation. As for the wedge test, the stress at the crack tip, together with the presence of moisture at the tip, make this a more severe test than soaked lap shear specimens or similar types and therefore a better measure of relative durability. 

Saponification Paints are most commonly used to protect steel from corrosion by seawater in marine applications and soil in the case of buried structures. Additional protection is often supplied by the application of cathodic protection to the steel. Any paint coating used in conjunction with cathodic protection must be resistant to the alkali which is produced on the steel at defect sites in the coating. The amount of alkali generated depends on the potential to which the steel is polarized. Some paint binders such as alkyds and vinyl ester are very susceptible to saponification, and should not be used on cathodically protected structures. Cathodic disbondment testing should be undertaken if the relevant information is not available. 

Electrolytic method This procedure is also known as the Williams Corfleld test d. It is based on loss of metal from iron electrodes buried in a water-saturated soil through which current from a 6-V battery is passed. It does not reflect field conditions and depends upon soil conductance under saturated conditions. 

Finally, it should be added that the extensive field tests made in the United States indicate that buried steel rusts less and less rapidly as time goes on, both as regards general attack and pitting. This can be illustrated by the typical results shown in Fig. 3.5. Field tests made in British soils by BISRA have not, however, exhibited the same tendency in these rusting has been roughly proportional to the duration of burial. 

In tests by BISRA, made over three years in a heavy clay soil at Binfield, additions of chromium and copper had no beneficial effect on the rusting of buried mild steel, as is shown in the following figures ... 

Additional evidence is available from tests made by the National Bureau of Standards on ten varieties of steel, which were buried in 15 typical American soils from 1937 to 1950The results showed that, with few... 

Stainless steels have not been widely used in applications where they are buried in soil, but some applications have involved underground service. Various stainless steels from the 13% Cr to the molybdenum-bearing austenitic types were included in the comprehensive series of tests in a variety of soils reported by Romanoff . High-chloride poorly-aerated soils proved most aggressive, but even here the austenitic types proved superior to the other metals commonly used unprotected. Of special interest is the fact that though corrosion was by pitting there was little or no increase in pit depth after the first few years. 

In tests carried out by the National Bureau of Standards in the USA specimens of copper alloys, lead, zinc and zinc alloys were buried at a number of different sites for periods varying from 11 to 14 years. The soils tested covered a pH range from 2-6 to 9-4 and resistivities ranged from 62 to 17 800 fi cm. The weight losses and maximum depths of pitting were recorded, and the results indicated that the most severe corrosion occurred in soils of poor aeration having high acid and soluble-salt contents. 

BISRA tests on galvanised steel pipe buried for five years at five different sites are described by Hudson and Acock The galvanised pipes resisted corrosion rather better than steel at all sites. Galvanised pipes of small diameter are frequently used to provide underground water services in farms and similar establishments, and little trouble is experienced. 

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