Elastic modulus dynamic

Nylon-6. Nylon-6—clay nanometer composites using montmorillonite clay intercalated with 12-aminolauric acid have been produced (37,38). When mixed with S-caprolactam and polymerized at 100°C for 30 min, a nylon clay—hybrid (NCH) was produced. Transmission electron microscopy (tern) and x-ray diffraction of the NCH confirm both the intercalation and molecular level of mixing between the two phases. The benefits of such materials over ordinary nylon-6 or nonmolecularly mixed, clay-reinforced nylon-6 include increased heat distortion temperature, elastic modulus, tensile strength, and dynamic elastic modulus throughout the —150 to 250°C temperature range. 

It is well known that for a given weight loss, thermal oxidation of graphite causes a larger reduction in strength and elastic modulus than radiolytic oxidation. Pickup et al. [78] showed the decrement in dynamic elastic modulus, E, due to thermal oxidation fitted an exponential relationship ... 

Rheologically, the BCC phase behaves as a solid, as expected, i.e. the dynamic elastic modulus is independent of frequency at high frequency in the linear... 

The dynamic elastic modulus (E ), the loss modulus (E"), and the tan 8 were measured simultaneously by the Rheovibron dynamic visco-elastometer model DDV-II (Toyo Measuring Instruments Co., Ltd.). Measurements were made at a frequency of 110 Hz, starting from —140°C and heating at 1°-2°C per minute until the samples became too soft to be tested. The readings were taken every 4°-8°C except in the transition zone when the readings were taken every 2°C. The sample chamber was kept dry by a stream of moisture-free nitrogen. 

Fig. 13. Reduced viscosity w. polymer concentration and dynamic elastic modulus vs. polymer concentration relationships. Left reduced viscosity measured at a shear rate of 3.4 sec. ...

In each case the attenuation of sound can be formally represented by defining a complex wavenumber, where the sound attenuation coefficient is the imaginary part of the wavenumber. The complex wavenumber also leads to the definition of a complex sound speed and a complex dynamic elastic modulus. 

If the setup makes it possible to measure the ultrasonic velocity only (or the dynamic elastic modulus), a similar technique can be developed for reconstruction the relaxation time and all other parameters characterizing the Jahn-Teller system. In this case we need two temperature dependences vg (T) (or cg (T)) the first one (denoted without superscript) obtained on the doped specimen and the second (superscript (2)) - on the un-doped. At high enough temperatures these dependences should be identical, while at low temperatures they should differ due to the Jahn-Teller effect. So, contribution of the Jahn-Teller system to the total dynamic modulus Acg may be written as... 

The resins in the friction dust area tend to be rigid and the flexibility and plasticity associated with the long alkyl chain of phenolic lipids have been used in natural rubber vulcanisation by for example incorporating crosslinking with phosphorylated cardanol (ref. 252). Unpolymerised CNSL phenols have been used in natural or diene rubber compositions for tyre treads to give an improved dynamic elastic modulus but with the same hardness as formulations without the phenolic addition (ref. 253). 

The dynamic elastic modulus of human hair has been reported to respond similarly to changes in relative humidity [27]. 

Frost resistance is determined by the number of freeze-thaw cycles that a particular concrete can withstand before reaching a given level of degradation. In general, the loss of mass or the decrease of dynamic elastic modulus are apphed as indexes of degradation. 

The value of tan 5 (at Tg) is lower for a filled elastomer than the pure elastomer (Medalia, 1978a Fletcher and Gent, 1984). This is due to the increase in dynamic elastic modulus of the filled compound for fhe higher temperature side of the Tg peak. The effect is governed by filler concenfration and loading. 

Static and Dynamic Elastic Modulus of Jointed Rock Mass... 

S.No. Sample/Inclinatlon P-wave Velocity, m/s S-wave Velocity, m/s Vp/Vs Dynamic elasticity modulus, GPa... 

Compressive strength ratio -Ratio of static elastic modulus Ratio of dynamic elastic modulus... 

Another exponential relations was established when the ratio of dynamic elastic modulus (E ) was plotted against the corresponding joint factor (Figure 16). For unconfined condition, the expression is as shown below. 

With the help of these equations the uniaxial compressive strength/elastic modulus of jointed rocks can be determined for known values ofjoint factor and uniaxial compressive strength/elastic modulus of intact rock. It is observed that the ratios of both static and dynamic elastic modulus decreases with an increase inthe jointfactorunder unconfinement. The test results of POP and the POP-cement mix specimens are given in Table 5. Figure 14 shows the experimental values of uniaxial compressive strength ratio versus joint factor along with a fitted curve. 

The plots of ratio of elastic modulus with the joint factor derived from the experimental data, for unconfined, are shown in Figure 15. The plots of ratio of dynamic elastic modulus with the joint factor are shown in Figure 16, which shows the variation of experimental values of uniaxial compressive strength ratio with joint factor for POP-... 

Figure 16. Ratio of dynamic elastic modulus versus joint factor...

Specimen Joint inclination parameter (n) Joint strength parameter (r) Joint frequency (Jn) Joint factor (Jf) Uniaxial compressive strength ratio (or) Ratio of elastic modulus (Er) Ratio of dynamic elastic modulus... 

INFLUENCE OF JOINTS ON STATIC AND DYNAMIC ELASTIC MODULUS... 

The influence of joints on static and dynamic elastic modulus was investigated based on the data provided in Table 4 and Table 5. Regression analysis was done for the data on ratios of static and dynamic elastic modulus of plaster of Paris (POP) specimen. Plaster of Paris-cement mix specimen and mixed data of plaster of Paris and Plaster of Paris-cement mix specimen. The curves were plotted for the ratio of static elastic modulus and dynamic elastic modulus for all the three groups of data. The plotted curves are shown in Figure 24 to Figure 26. Figure 24 shows the experimental values of ratio of static elastic modulus versus ratio of dynamic elastic modulus for POP specimens. Figure 25 shows the trend of ratio of static elastic modulus versus ratio of dynamic elastic modulus for POP-cement mix specimens. The plot of ratio of static elastic modulus versus ratio of dynamic... 

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