The role of stress

As commented earlier, the rate of loss of strength of a joint under environmental attack will usually be faster if a tensile or shear stress is present 145,126-130], albeit an externally applied stress or internal stresses induced by adhesive shrinkage (incurred during cure) or by adhesive swelling (due to water uptake) [131,132]. Such stresses render primary and secondary molecular bonds more susceptible to environmental attack and also probably increase the rate of diffusion and the solubility in the adhesive of the diffusing medium [133-135]. 

Of particular interest is whether there is a lower limit to the applied stress below which no environmental attack is observed and this has been investigated in some detail using a fracture mechanics approach [36,45,136,137]. The TDCB geometry (see Table 7.1), consisting of aluminium alloy beams bonded with an epoxy adhesive, has been widely employed and the commonly used experimental technique has been to place this specimen under an applied load in the environment of interest and monitor the rate and locus of crack growth. The typical observation is that the cohesive in adhesive starter crack does not 

Ingressing debondrng in interfacial regions, increasing with time 

From such data as that shown in Fig. 8.26 it was concluded that there was a minimum value of Gic, denoted Giscc, below which slow crack growth would not occur in aqueous environments. Such a minimum value implies that there is a 

However, from theoretical considerations of the mechanisms of attack a clearer picture emerges. Recalling Equation 7.8, the adhesive fracture energy, Gic, may be expressed by  

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Piazza, P. V. and Le Moal, M. The role of stress in drug self-administration. Trends Pharmacol. Sci. 19 67-74, 1998. 

Canesi, L. et al., Signalling pathways involved in the physiological response of mussel hemocytes to bacterial challenge the role of stress-activated p38 MAP kinases, Devel. Compar. Immunol., 26, 325, 2002. 

Rodent Models and the Elucidation of the Role of Stress on the Exacerbation... 

RODENT MODELS AND THE ELUCIDATION OF THE ROLE OF STRESS ON THE EXACERBATION OF DISEASE... 

Buss, I.O., Rasmussen, L.E. and Smuts, G.L. (1976) The role of stress and individual recognition in the function of the African elephant s temporal gland. Mammalia 40, 437—451. 

Nencini P, Ahmed AM, Anania MC, Moscucci M, Paroli E. (1984). Prolonged analgesia induced by cathinone. The role of stress and opioid and nonopioid mechanisms. Pharmacology. 29(5) 269-81. 

Figure 5.7 The role of stress caused by lattice mismatch between SAM and substrate illustrated in (a) and (b) by a cross-section of a SAM (x-z plane), indicated adsorption sides (x-y plane) and the molecule-substrate interaction potential V where the solid circles indicate the energy of an adsorption site for a particular SAM molecule, (a) For rigid molecules, stress is mainly released by defect formation in SAM, which results in a layer of rather low crystallinity and small domains, (b) Molecules...

Shellne, Y.I. (2000) 3D MRI studies of neuroanatomlcal changes in unipolar major depression the role of stress and medical com-orbldlty. Biol Psychiatry 48 791-800. 

Baertschi SW. The Role of Stress Testing in Pharmaceutical Product Development, presented at the American Association of Pharmaceutical Scientists Midwest Regional Meeting, Chicago, IL, May 20, 1996. 

A synergistic effect between the role of stress and environmental agents such as O3, SO2 and NO2 on degradation of the mechanical properties of Nylon fibers has been observed. This... 

This integral representation has the advantage that its formulation does not require an appeal to models based on dashpots and springs, and it is purely formal. Alternatively, the roles of stress and strain could be reversed, giving... 

Hydrogen diffusion within metals is also known to be governed by the stress-strain state therein. Roughly, it may be considered that hydrogen diffuses in metals obeying a Fick type diffusion law including additional terms to account for the effect of the stress-strain state. Concerning the role of stress, this is... 

Mulholland, S.E., Lee, S., McAuliffe, D.J. and Doukas, A.G. (1999) Cell loading with laser generated stress waves the role of stress gradient . Pharm. Res. 16, 514-518. 

The importance of psychological factors in the pathogenesis of PUD remains controversial. Clinical observation suggests that ulcer patients are adversely affected by stressful life events. However, results from controlled trials are conflicting and have failed to document a cause-and-effect relationship. It is possible that emotional stress induces behavioral risks such as smoking and the use of NSAIDs, or alters the inflammatory response or resistance to HP infection. The role of stress and how it affects PUD is complex and probably mnlti-factorial. 

Patients who deny the role of stress have a poorer prognosis (Sparks et al. 1994b). 

These equations are plotted in Figure 7-2. They are formally identical to the compliance response of a Voigt element in series with a spring when the entire model is subjected to a sinusoidal stress. The complex dielectric constant is thus the analogue of the complex compliance, with the electric field playing the role of stress and the electric displacement 4 7rcr playing the role of strain. 

With the X-ray technique described stresses in polymer wear films can be measured. One could incorporate a pin-on-disk friction device within the opening of the X-ray camera and conduct in situ measurements. The stresses developed in the film with repeated passes, increasing load, varied sliding speeds and polymer compositions can be measured. This could lead to a better understanding of the role of stresses in polymers on their wear behavior. 

During the doping of the glass, the emerging stresses are also accompanied by the relaxation processes. They are reflected in the reduction of the role of stresses in the changes of the... 

R. Oltra, V. Vignal, Recent advances in local probe techniques in corrosion research—analysis of the role of stress on pitting sensitivity, Corros. Sci. 49 (2007) 158—165. 

When grouting pressure exist in the seepage channel, the role of stress in micro cracks shown in Fig 3, the slurry pressure at the end face of the channel into the formula (1) can be obtained ... 

Bhandari, S. (1979). On the role of stress waves and quasi-static gas pressure in rock fragmentation by blasting. Acta Astronautica, 6, 365-383. doi 10.1016/0094-5765(79)90104-8doi 10.1016/0094-5765(79)90104-8... 

Steigerwald EA, Schaller FW, Troiano AR. The role of stress in hydrogen induced delayed failure. Trans. Metall Soc. AIME, 1960 218 832-841. 

The tendency for this information to remain uncoupled is prevalent. For example, the connection between bearing capacity and movement (consolidation) is not so obvious to the students - analyses are performed as two standalone activities that are not connected or related in any way. Therefore, considerable time and effort is spent in the learning seminars trying to unify these concepts. The role of stress history, overconsolidation, rate of loading, particle size distribution and soil classification in both the strength and compressibility ofthe soil are debated. In addition. 

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