Continuous immersion

So aluminium alloy is good it resists all the fluids likely to come in contact with it. What about GFRP The strength of GFRP is reduced by up to 20% by continuous immersion in most of the fluids - even salf water - with which it is likely to come into contact but (as we know from fibreglass boats) this drop in strength is not critical, and it occurs without visible corrosion, or loss of section. In fact, GFRP is much more corrosion-resistant, in the normal sense of loss-of-section, than steel. 

A comprehensive table of corrosion rates in sea water has been compiled by LaQue . This appears to show no obvious dependence of corrosion rates on the geographical location of the testing site, and few of the rates depart widely from an average of 0-11 mm/y. It is suggested that a figure of 0-13 mm/y may be taken as a reasonable estimate of the expected rate of corrosion of steel or iron continuously immersed in sea water under natural conditions, in any part of the world. 

In considering the requirements of paints for marine use it is necessary to distinguish between the, parts of ships that are subject to different conditions of service. The exterior area of ships may be diyided broadly into three parts the bottom, which is continuously immersed in the sea b) the... 

At the request of an international petroleum company, a major manufacturer and supplier of down-hole equipment performed tests of the various elastomers commonly used in the construction of packers and other oil field tools. Seven of the nine most commonly used thermoplastic materials were found to be completely inert to TKPP solutions. The test included continual immersion in saturated TKPP for 21 days at 280°F. Only two elastomers, Vi-ton and Fluorel, showed any adverse reaction. O-rings made from these two elastomers showed minor cracking at the termination of the test. A listing of the elastomers that tested inert to TKPP solutions include nitrile, saturated nitrile (HNBR), Aflas, Kalrez, PEEK, Glass-filled Teflon, and Ryton. Several of these elastomers are attacked or degraded by conventional clear completion fluids containing calcium and zinc halides. The inertness of commonly employed elastomers to TKPP is an important advantage for TKPP fluids in normal operations. 

Atlantic salmon, Salmo salar, fertilized eggs, continuous immersion in 92.5 Bq 137Cs/L or 185 Bq "Sr/L Brown trout, Salmo trutta Increased mortality of embryos and fry 10... 

Fertilized eggs continuously immersed in No effect on hatch or developmental 10... 

The permeation of water into polymers is particularly slow and can require a very long time to reach equilibrium. ISO 62 [17] provides for continuing immersion until equilibrium is reached and describes how the equilibrium uptake can be estimated from results at lower times by assuming that the absorption process follows Fick s laws. 

Continuous immersion of the fabric in a dyebath and removal of the excess of liquor by squeezing or suction (padding). 

Table 7-5. Percentage of initial a radioactivity dissolved from Pu02 particles each week after continuous immersion or subjection to 4 day/3 day wet/dry cycles (Mewhinney et al., 1987).

Continuous immersion of these CHEMFETs in aqueous solution for 8 weeks showed only a minor decrease in the slope to 54 mV.(pK+) 1. This surprizing stability might be due to the bond formation of the membrane between the silanol groups and the gate oxide. 

Test Method for Durability of Sealants Exposed to Continuous Immersion in Liquids... 

The bake systems demonstrate excellent resistance to alkalies including sodium hydroxide at concentrations up to 73%. Generally the temperature resistance to continuous immersion is suitable up to 200°F (93°C). 

The acid resistance of epoxy phenolics to continual immersion conditions would generally be poor to fair. Special formulations are available to provide resistance to dilute sulfuric, hydrochloric, nonoxidizing mineral acids, and fatty acids. Many systems are available for resistance to spillage and fumes from most acids with the exception of nitric, formic, chromic or hydrofluoric. 

Accelerated testing was performed by immersing polyurethane liner specimens in water at several elevated temperatures. Periodically, the samples were removed from their respective water baths, dried and then subjected to hardness and compressive stress-strain measurements. An Arrhenius relationship was employed to estimate the expected life of the pads under the severe condition of being continually immersed in water at 35 C. The pads were considered to have failed when their compressive stress fell to 80 percent of the original value. 

However, some archaeological wooden artifacts have survived, at least in part. Before discovery, most of these objects have either been in a relatively dry environment, frozen, or continuously immersed in water. These conditions limit the moisture, air, or temperature needed for the growth of decay, and thus they prolong the life of the wood. 

The thickness of the encapsulating layer has been taken from Tannenberger to be 0.2 fj,m. The resistance of the insulating layers were calculated from the recorded voltammograms obtained between 1.0 V and —1.0 V in the solution immediately after the thermal curing step and then at various intervals during continuous immersion in 0.1 M NaCl. The resistivity was calculated using the determined value of the insulator thickness. The initial resistivity was 1.2 X 10 ft cm and after the period of 10 days was decayed to 0.3 X 10 ft cm. 

Protected against submersion. Suitable for continuous immersion in water. 

Urethanes are not high temperature polymers. Continuous service applications at more than about 100°C are not recommended. They are subject to hydrolysis other materials should be considered in applications which involve long-term continuous immersion in water. They undergo autoxidation on thermal or ultraviolet activation. Poly(ester-urethanes) are subject to microbiological degradation. 

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