Specimen ambient temperature

The specimens have been cleaned according to the NFA 09.521 standard, dried at ambient temperature 5 minutes, immerged 10 minutes in the penetrant and hung up 10 minutes. The excess penetrant has been removed at the washing unit. The developer has been applied immediately after the drying, and the indications examination has been performed 5, 10 and 20 minutes after the developer application. 

Thickness. The traditional definition of thermal conductivity as an intrinsic property of a material where conduction is the only mode of heat transmission is not appHcable to low density materials. Although radiation between parallel surfaces is independent of distance, the measurement of X where radiation is significant requires the introduction of an additional variable, thickness. The thickness effect is observed in materials of low density at ambient temperatures and in materials of higher density at elevated temperatures. It depends on the radiation permeance of the materials, which in turn is influenced by the absorption coefficient and the density. For a cellular plastic material having a density on the order of 10 kg/m, the difference between a 25 and 100 mm thick specimen ranges from 12—15%. This reduces to less than 4% for a density of 48 kg/m. References 23—27 discuss the issue of thickness in more detail. 

The addition of Vamac B-124 to ethyl cyanoacrylate has a more pronounced effect on peel strength, both at ambient temperature and after thermal exposure. After 24 h at ambient temperature, the peel strength of the rubber-toughened formulation is almost 40% greater than the control formulation A without rubber. After heating the test specimens for 2 h at 121°C, the peel strength of formulation A, is almost non-existent, while that of C has increased significantly, as seen in Fig. 7. 

Aqueous environments Neutral chloride solutions do not corrode titanium alloys at ambient temperatures, and smooth statically loaded specimens of susceptible alloys do not exhibit failure. In order to nucleate cracking it appears probable that the protective oxide film on alloys must be destroyed and its repair must not occur. If this breakdown occurs then cracking is observed in susceptible alloys. Consequently, the type of test and the type of specimen employed in any selected test are both important considerations, particularly in alloys exhibiting low susceptibility. 

The role of the stress in embrittlement and stress-corrosion processes has been examined in some detail by employing the slow strain-rate technique . Specimens of alloy 7179-T651 tested in air or in vacuum after pre-exposure to water at 70° C or in water at various potentials at ambient temperature exhibited a reversible embrittlement in excess of that arising from testing in moist air . The embrittlement was attributed to hydrogen absorption, and recovery was thought to be due to loss of hydrogen (particularly under vacuum) or to diffusion to traps. Potentiostatic tests revealed... 

Strictly the terms brittle and tough fracture can only be applied to failure under carefiilly specified test conditions. That is to say that the statement that a glassy polymer, such as poly(methyl methacrylate), undergoes brittle fracture at ambient temperatures needs qualifying test conditions must be stated. These are usually that the material has been formed into a dumbbell shaped specimen. 

The state of the surface of a brittle solid has been found to exert a considerable influence on the mechanical behaviour observed it is at least as important as the underlying molecular constitution in this regard. The presence of microscopic scratches, voids, or other imperfections will seriously weaken the tensile strength of specimens of glassy polymer, such as poly(methyl methacrylate) at ambient temperatures. 

Volume fraction of network in specimen swollen with benzene at ambient temperature. 

In point of fact, when considering the weathering performance of plastic materials, there exists even more interplay between weathering factors than the factors noted above, such as the ambient temperature, temperature of the actual specimens under exposure and the humidity during exposure of the materials. If the... 

Tensile tests on cured BCB oligomer were done at ambient temperature on dry and saturated dogbone shaped specimens. The results are shown in Table I. 

A necessary preface to a description of the procedure is that the solvent and the precipitant must be purified to exhaustion by contact with successive specimens of the acid to be purified. The acid A is dissolved in the minimum amount of solvent S. The precipitant P is then added under isothermal conditions to the solution until roughly one half to three quarters of A has been precipitated. At this stage there is a three-phase system present (vapour and two liquids) with three (or more) components (A, S, and Imp where Imp denotes an impurity), and the impurities are partitioned between A and the mixture of S and P. This mixture is separated from A by decantation or syphoning, A is redissolved in S and reprecipitated by the addition of P. At all stages of this process the mixtures must be stirred efficiently but so gently that an emulsion is not formed. It happens quite often that an acid A with a melting point near or above ambient temperature will start to crystallise after the first or second extraction. 

In order to investigate the UV Stability of ABS, specimens were exposed in a weatherometer. The ambient temperature of 30°C ensured that the mechanism of UV degradation was not interfered by thermal effects The specimens were exposed under accelerated conditions for 3 months, with periodic assessments of their performance (62). 

The DMA was operated in the fixed frequency mode at 1 Hz and a peak-to-peak amplitude of 0.06 mm. A DuPont Liquid Nitrogen Cooling Apparatus (LNCA-II) was used to achieve sub-ambient temperatures. The temperature profile used was a ramp to — 20°C, soak for 5 min, and then ramp at 5°C/min to 220°C. Three specimens were tested for each blend. 

For optical microscopy, hairy root specimens were fixed with 3 % formaldehyde in 50 mol m phosphate buffer (pH 6.8) for 1 h at ambient temperature. Cross-sections of the specimen were prepared using a sliding microtome equipped with a specimen-freezing stage. The sections were examined with microscopes under conventional or fluorescent light (excitation wavelengths of 520-550 nm and emission wavelength of >580 nm). 

The guarded hot plate is a standard instrument for measuring the relative thermal resistance of textiles as heat flows from a heated plate in contact with the textile and dissipates into still air at a lower ambient temperature via radiation, conduction, and convection. By design, it minimizes errors due to edge heat losses and validates the total quantity of heat flowing through the specimens. Convection and surface radiation can be controlled by use of a hood (2j+). Simpler devices such as the Reeves warmth tester and a chamois-covered copper cylinder also measure thermal... 

The collection of plant tissue is quite different from animal tissue collection. The discussion of collection of plant and animal tissue by Dessauer et al.2S is detailed and helpful. However, the recommendations for procedures unique to plant tissue collection are somewhat misleading and outdated, especially when tropical collections are involved. Plant tissue can now be collected and transported as either fresh tissue (leaves and/or shoot cuttings) or preserved tissue the latter either as cryopreserved tissue (liquid nitrogen or dry ice) or as dried tissue (air-dried, herbarium-dried, lyophilized, or chemically dried). Ambient-temperature liquid chemical preservation techniques (such as those routinely done for herbarium plant specimens in the tropics) so far have been ineffective in maintaining adequate yields of high-quality DNA.15 It should be stressed again that the manner of collecting plant tissue is dictated by several other factors what macromolecule (DNA, RNA, or isozymes) will be examined, what type of nucleic acid extraction method will be used (or, more impor-... 

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