Moisture penetration

Type and specifications on fan driver, gear types, pow er voltage, phase, cycles. Motors should at least meet specifications equivalent to totally enclosed, fan cooled, or if in explosive hazardous area, TEFC Class I, Group D (except this not acceptable in hydrogen or acetylene atmosphere). Due to moisture conditions around this equipment, it should be protected against moisture penetration and corrosion. 

Since full analyses are carried out, a lot of data are generated. Every parameter is reviewed for trends that signal product aging or outright decomposition of the active principle this can be as cosmetic in nature as discoloration or as potentially hazardous as buildup of toxic derivatives. If the drug substance is an ester, for example, hydrolysis, particularly if moisture penetrates the primary packaging material, will decompose the compound into its acid and alcohol components. From a pharmaceutical or medical viewpoint, even if there is no toxicity issue involved, this will result in a loss of bioavailability. Even this is to be avoided because subpotency introduces therapeutic uncertainty and can go as far as lethal undertreatment. 

A barrier to prevent moisture penetration along the interface... 

Epoxy glasses aged at 140 °C were subjected to 40 °C/98 % relative humidity moisture penetration. Figure 31 shows the results of this transport experiment. We observed both a decrease of initial sorption kinetics as well as a decrease of equilibrium sorption level as a function of aging time. This supports the idea that during sub-Tg annealing, the resin contrasts and densities, resulting in decreased free volume. 

Initial studies indicated that sulfur alone was not adequately resistant to moisture penetration. However, it was discovered that the addition of an oil wax sealant over the... 

Cathodic disbondment is associated with over-the-ditch applications of tape and, to a lesser extent, with shop- or railhead-applied tape. Moisture penetration into the overlap is also a potential problem. For this reason, and to minimize damage during handling, a double wrap is preferred. The potential problems with polyethylene tape have been avoided in many cases, and there is a long history of successful applications. 

Apack s Canadian subsidiary is promoting use of its composite in hot- and cold-drink disposable cups to replace EPS. Apack Canada s cups are foamed to 0.2 g/cc density, reportedly providing better insulation than paper cups. A co-polyester coating prevents moisture penetration, permits quality printing, and provides enough insulation (in hot cups) to dispense with costly paper sleeves. The sprayed-on coating uses a blend of an Eastman co-polyester and a second biodegradable resin to get a balanced viscosity. 

Cerium(lV) compounds with suitable reducing agents, readily initiate the redox polymerization of, for example, vinyl monomers [22]. This property is used to initiate graft polymerization of vinyl monomers onto cellulose, wool, starch, cotton, etc. in order to, e.g. improve mechanical strength, resist moisture penetration and reduce micro-organism attack. 

High air humidity is not the only reason for microbial growth indoors. Microbial growth is often caused or at least promoted by moisture penetration through building materials. The causes of moisture penetration can be divided into construction flaws or user errors. Thermal bridges and defective isolation are considered as construction flaws. 

As it seems reversed- phase systems favour the use of the chromatographic method when determining the Henry constants. However, when polar adsorbents and nonpolar eluent are used while study the adsorption, there is always the danger that some moisture penetrates from the eluent on to the adsorbent resulting in a gradual decrease of the retention time of the compounds under investigation. 

SiNx/ acryl-passivated TFTs were measured after 3-hour humidity-temperature test. Fig. 11 (right) shows transfer curves before and after the humidity-temperature test. The threshold voltage shift was 1 V after 3-hour humidity-temperature test. It was reduced compared to the threshold voltage shift of the single acryl passivated TFT (2.8 V). 50 nm-thick SiNx could somewhat prevent moisture penetrating into TFT. 

The effect of passivation layer on the performances of a-Si H TFT imder mechanical stress was investigated. The acryl-passivated TFT could endure mechanical stress better than the SiNx-passivated TFT. However, a larger threshold voltage shift was observed for the acryl-passivated TFT when a humidity-temperature test was carried out. The hybrid passivation, which was composed of SiNx and acrylic polymer was proposed. It secured the degradation of electrical performances under the mechanical stress and somewhat prevented moisture penetrating into TFT. 

Figure 6 shows the performance of encapsulated devices under the highly accelerated stress test which utilizes the following conditions 145°C, 85% relative humidity, 37 psig, and electrical bias. The bias on this test is cycled specifically, the bias is initially off to allow for full moisture penetration and then turned on. These cycles are repeated throughout the test. The stable bromine CEN compound took 2500 hours to reach 50% failure rate, compared to the standard resin compound at 1900 hours. 

Verify that all lubricants such as oil and grease are kept in clean, sealed containers so that no dust or moisture penetrates and the oxidizing effect of the air is minimal. 

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