author apos s presentation of material

... knowledge of kinetics is valuable because it leads to prediction of the rates of materials processes of practical importance Analyses of the kinetics of such processes are included here as an alternative ... Conditions 3.5 Stress and Diffusion 3.5.1 Effect of Stress on Mobilities 3.5.2 Stress as a Driving Force for Diffusion: Formation of Solute-Atom Atmosphere around Dislocations 3.5.3 Influence of Stress ... engineering Many processes are of interest, including changes of size, shape, composition, and structure In all cases, the system must be out of equilibrium during these processes if they are to occur...

Ngày tải lên: 27/06/2014, 23:20

... rightmost side of a k-stratum consists of a series of shrinks first, followed by a series of growths By Lemma 3.6 (2c4), these shrinks are a part of the horizontal strip gained in the k-stratum Also ... and our assumption on the positions of X and Y Now in the sliding phase, each of these k s either stays put, moves left, or moves up When the sliding is finished, the tableau must be semistandard; ... bumping phase, nor is any cancelled This assures that, when sliding starts, the bottoms of the 1st through cth columns are still occupied by k s, as was the case before the bumping starts, by (2c3)...

Ngày tải lên: 07/08/2014, 08:22

... town is in an incredible state of preservation It offers some of the most densely concentrated sights in Vietnam with its old streets bordered with ancient houses and assembly halls, its pagodas, ... the year this small city is bustling with tourists Lots of tourists also means lots of hawkers, cyclo drivers and children selling chewing gum It sometimes seems impossible to walk more than 10 ... a great diversity of ecosystems including offshore coral reefs, freshwater swamp forests, mangrove forests, small freshwater lakes, and sandy beaches.The climate of Ha Long Bay is tropical, being...

Ngày tải lên: 08/08/2014, 11:22

... general, this consideration holds for all autoimmune diseases Psychiatric presentation of primary SS also suggests that mental disorders not occur only as a response to a psychological distress or a ... the present article, we report two cases of mental disorders as clinical presentations of primary SS, suggesting that psychiatrists should keep in mind that SS can be a potential cause of psychiatric ... neuropathological mechanisms of SS are unknown In CNS-SS, the most serious neuropsychiatric disorder appears to result from ischaemic damage caused by vasculitis [7], but the role of anti-Ro/SS-A alone or...

Ngày tải lên: 08/08/2014, 23:21

... attrition of EDM muscle following long-standing Kienböck s disease, but none of these authors reported these as the presenting complaints The original description of Vaughan-Jackson syndrome [1] was of ... full functionality of his hand and wrist Conclusions Kienböck s disease, though rare, is an important cause of spontaneous extensor tendon rupture Attrition rupture of tendons is a well-known problem ... was present over the dorsum of the proximal end of the space between the fourth and fifth metacarpal bones A diagnosis of spontaneous rupture of the extensors to the ring and little fingers was...

Ngày tải lên: 10/08/2014, 23:22

... knowledge of kinetics is valuable because it leads to prediction of the rates of materials processes of practical importance Analyses of the kinetics of such processes are included here as an alternative ... Conditions 3.5 Stress and Diffusion 3.5.1 Effect of Stress on Mobilities 3.5.2 Stress as a Driving Force for Diffusion: Formation of Solute-Atom Atmosphere around Dislocations 3.5.3 Influence of Stress ... engineering Many processes are of interest, including changes of size, shape, composition, and structure In all cases, the system must be out of equilibrium during these processes if they are to occur...

Ngày tải lên: 11/08/2014, 10:22

... gradients of an isotope of that material In this section we discuss self-diffusion of an isotopic species in a chemically homogeneous binary solution consisting of atoms of types and in the presence ... diffusion zone compared to the extent of the specimen in the diffusion direction, compatibility stresses are pure shear stresses, and if the stresses exceed the crystal 's yield stress, the onset of ... that species loses net mass and contracts On the other hand, the region initially richer in the more slowly diffusing species gains net mass and expands This process, which establishes a mass flow...

Ngày tải lên: 11/08/2014, 10:22

... effects of stress in isolation, we can study the main aspects of diffusion in stressed systems 3.5.1 Effect of Stress on Mobilities Consider again the diffusion of small interstitial atoms among ... and stress gradients exist, the stress will exert a force, as discussed in the following section 17The tensor nature of the diffusivity (mobility) in anisotropic materials is discussed in Section ... a single-crystal wire containing dislocations possessing Burgers vectors inclined at various angles to the stress axis The diffusion potential a t dislocations (each acting as sources or sinks)...

Ngày tải lên: 11/08/2014, 10:22

... methods for solving partial-differential equations We first discuss some fundamental-source solutions that can be used to build up solutions t o more complicated situations by means of superposition ... diffusion results in linear systems of diffusion equations A linear transformation of the concentrations produces a simplified system of uncoupled linear diffusion equations for which general solutions ... Therefore, as cy becomes small, or at short times t , or as D increases, c(0, t ) approaches CO For small a,surface desorption is compensated by diffusion from the bulk, so that c(0, t ) decreases slowly...

Ngày tải lên: 11/08/2014, 10:22

... dumbbells jump between the different types of sites The overall response of the crystal t o such a stress cycle is shown in Fig 8.16 When the stress uo is applied suddenly, the crystal instantaneously ... curves, as discussed in Section 9.2.3 Dislocations, grain boundaries, and surfaces can possess widely differing structures, and these structural variations affect their diffusivities to significant ... model for a standard anelastic solid serves this purpose; it consists of two linear springs, S and S2 , and a dashpot, D , which is a plunger immersed in a viscous fluid The dashpot changes length...

Ngày tải lên: 11/08/2014, 10:22

... 10 SMALL ATOMS (MOLECULES) IN GLASSY POLYMERS 239 with p arises from the successive saturation of the lower-energy sites as the concentration is increased This causes a progressive decrease of ... rates become significant, and significant climb is then possible Climbing dislocations act as sources and sinks for point defects This chapter establishes some of the basic kinetic features of ... difficulty Also, as might be expected, the diffusion on most surfaces is anisotropic because of their low two-dimensional symmetry When the surface structure consists of parallel rows of closely spaced...

Ngày tải lên: 11/08/2014, 10:22

... forces the efficiency is often relatively low Vicinal heterophase interfaces can act as overall sources (or sinks) for fluxes of solute atoms by the motion across their faces of line defects possessing ... INTERFACES AS SOURCES A N D SINKS FOR ATOMIC FLUXES The basic mechanisms by which various types of interfaces are able to move nonconservatively are now considered, followed by discussion of whether ... dissolution ledge spirals as discussed in Section 12.2.2 Probable observed examples of such dislocation growth or dissolution spirals on grain boundaries are shown in Fig 13.5 The rates of boundary...

Ngày tải lên: 11/08/2014, 10:22

... vapor of a crystal possessing vicinal faces The shape that the crystal assumes depends upon the number and rate at which ledges move across its surfaces When one of the surfaces consists of a series ... center The pressure due to this curvature therefore induces growth Grains with fewer than six sides show the opposite behavior, whereas grains with six sides possess flat sides and are static Figure ... vertex The grain structure during growth will generally consist of a distribution of grains possessing a range of sizes (volumes) and various numbers of faces and edges Plateau s laws will be obeyed...

Ngày tải lên: 11/08/2014, 10:22

... also scales as 1/X For surface diffusion, one of the cross-sectional area s dimensions is 6, the thickness of the high-diffusivity surface layer, independent of system size The remaining cross-sectional ... determination of the shear stress acting on each boundary segment EXERCISES 411 Solution Expressions for the shear stresses at the three types o f boundary segments may be obtained by the simultaneous solution ... rate of elongation of a wire possessing a bamboo-type grain structure is given in Section 16.1.3 An essential aspect of the analysis is the assumption that the stress-induced atomic transport...

Ngày tải lên: 11/08/2014, 10:22

... cluster, any shear stresses across it will be unrelaxed, since no interface sliding is possible in complete contrast to the case of the incoherent interface discussed above Eshelby treated systems ... case of phase transformations) is absent and the interface s core structure consists of all “bad material. ” It is generally assumed that any shear stresses applied across such an interface can then ... volume of the system is not constant, and substantial expansions or contractions of the phases present will occur which cannot be ignored These changes in volume will cause the phases to be displaced...

Ngày tải lên: 11/08/2014, 10:22

... kinetics of materials and averaging, and irreversible thermodynamics, and mechanisms of kinetic processes, construction of theories for, general description of, relation to classical thermodynamics, ... glide vs climb, 253 jogs, 262 kinks, 262 line tension of 257 dislocations in interfaces anticoherencv dislocations 598 as sources and sinks for atomic fluxes, 317 coherency dislocations, 598 dislocations ... kinetics, 267 dislocations as sinks for excess vacancies, 269 edge, mixed, and screw dislocations, 268 efficiency, 268 experimental observations, 269 formation of helical dislocations, 268, 279 osmotic...

Ngày tải lên: 11/08/2014, 10:22

... imaging of the brain, which may display atrophic alterations, mass lesions and hydrocephalus This explains the sometimes focal neurology secondary to solitary mass lesions, for example, generalised ... determination should be the next option [1] Although the molecular PCR assessment of cerebral biopsies has the highest diagnostic yield in neurological WD, its associated morbidity means that analyses of ... possible irreversible damage to the brain caused by WD disease of the CNS Figure pinal fluid acid-Schiff-positive cells obtained from cerebrosPeroxidase Peroxidase acid-Schiff-positive cells...

Ngày tải lên: 11/08/2014, 21:22

... knowledge of kinetics is valuable because it leads to prediction of the rates of materials processes of practical importance Analyses of the kinetics of such processes are included here as an alternative ... Conditions 3.5 Stress and Diffusion 3.5.1 Effect of Stress on Mobilities 3.5.2 Stress as a Driving Force for Diffusion: Formation of Solute-Atom Atmosphere around Dislocations 3.5.3 Influence of Stress ... engineering Many processes are of interest, including changes of size, shape, composition, and structure In all cases, the system must be out of equilibrium during these processes if they are to occur...

Ngày tải lên: 13/08/2014, 05:20

... effects of stress in isolation, we can study the main aspects of diffusion in stressed systems 3.5.1 Effect of Stress on Mobilities Consider again the diffusion of small interstitial atoms among ... gradients of an isotope of that material In this section we discuss self-diffusion of an isotopic species in a chemically homogeneous binary solution consisting of atoms of types and in the presence ... diffusion zone compared to the extent of the specimen in the diffusion direction, compatibility stresses are pure shear stresses, and if the stresses exceed the crystal 's yield stress, the onset of...

Ngày tải lên: 13/08/2014, 05:20

... class of initial and boundary conditions, the soluFor tion has theorems of uniqueness and existence as well as theorems for its maximum and minimum values Many texts, such as Crank s treatise ... In general, the properties of crystals and other types of materials, such as composites, vary with direction (i.e., macroscopic materials properties such as mass diffusivity and electrical conductivity ... DIFFUSION diffusion, whereas the small interstitial C atoms were mobile Si increases the activity of C in Fe Explain these results in terms of the basic driving forces for diffusion Solution As...

Ngày tải lên: 13/08/2014, 05:20