Internal tension

Okubo, S., Fukui, K. (1996). Complete stress-strain curves for various rock t5q)cs in uniaxial tension. International Journal ofRockMechanics and Mining Sciences Geomechanics Abstracts, 33,549-556. doi 10.1016/0148-9062(96)00024-1... 

Brara, A., Klepaczko, J. R. (2007) Fracture energy of concrete at high loading rates in tension, International Journal of Impact Engineering, 34 424-35. 

Beuth, J. L. (1992), Cracking of thin bonded films in residual tension. International Journal of Solids and Structures 29, 1657-1675. 

Flow Past Deformable Bodies. The flow of fluids past deformable surfaces is often important, eg, contact of Hquids with gas bubbles or with drops of another Hquid. Proper description of the flow must allow for both the deformation of these bodies from their shapes in the absence of flow and for the internal circulations that may be set up within the drops or bubbles in response to the external flow. DeformabiUty is related to the interfacial tension and density difference between the phases internal circulation is related to the drop viscosity. A proper description of the flow involves not only the Reynolds number, dFp/p., but also other dimensionless groups, eg, the viscosity ratio, 1 /p En tvos number (En ), Api5 /o and the Morton number (Mo),giJ.iAp/plG (6). 

G. Luxa and co-workers. Item D. Paschen CurveforSF, 1975 CIGRE International Conference on Earge High Tension Electrical Systems. 

Foam Inhibitors. Methyl sihcone polymers of 300-1000 mm /s(= cSt)) at 40°C are effective additives at only 3—150 ppm for defoaming oils in internal combustion engines, turbines, gears, and aircraft appHcations. Without these additives, severe churning and mixing of oil with air may sometimes cause foam to overflow from the lubrication system or interfere with normal oil circulation. Because sihcone oil is not completely soluble in oil, it forms a dispersion of minute droplets of low surface tension that aid in breaking foam bubbles. 

The atoms and molecules at the interface between a Hquid (or soHd) and a vacuum are attracted more strongly toward the interior than toward the vacuum. The material parameter used to characterize this imbalance is the interfacial energy density y, usually called surface tension. It is highest for metals (<1 J/m ) (1 J/m = N/m), moderate for metal oxides (<0.1 J/m ), and lowest for hydrocarbons and fluorocarbons (0.02 J /m minimum) (4). The International Standards Organization describes weU-estabHshed methods for determining surface tension, eg, ISO 304 for Hquids containing surfactants and ISO 6889 for two-Hquid systems containing surfactants. 

Grease Retention, Wrinkle Resistance, and Durable Press. On bending or creasing of a textile material, the external portion of each filament in the yam is placed under tension, and the internal portion is placed in compression. Thus, the wrinMe-recovery properties must be governed in part by the inherent, tensional elastic deformation and recovery properties of the fibers. In addition to the inherent fiber properties, the yam and fabric geometry must be considered. 

Evidence suggests that there is a threshold tensile stress at which void nucleation occurs and spall fracture initiates. Materials subject to transient internal tensions can support tensile stresses significantly in excess of this threshold level, however. Such behavior is a consequence of kinetics and inertia associated with the nucleation and growth of voids during spall. A fairly large body of experimental and theoretical literature on spall phenomena exists and many aspects of the effect are reasonably well understood. Review articles on spall (Curran et al., 1977 Davision and Graham, 1979 Curran, 1982 Meyer and Aimone, 1983 Novikov, 1981) provide access to most of the literature on the subject. 

There are four commonly occurring states of stress, shown in Fig. 3.2. The simplest is that of simple tension or compression (as in a tension member loaded by pin joints at its ends or in a pillar supporting a structure in compression). The stress is, of course, the force divided by the section area of the member or pillar. The second common state of stress is that of biaxial tension. If a spherical shell (like a balloon) contains an internal pressure, then the skin of the shell is loaded in two directions, not one, as shown in Fig. 3.2. This state of stress is called biaxial tension (unequal biaxial tension is obviously the state in which the two tensile stresses are unequal). The third common state of stress is that of hydrostatic pressure. This occurs deep in the earth s crust, or deep in the ocean, when a solid is subjected to equal compression on all sides. There is a convention that stresses are positive when they pull, as we have drawn them in earlier figures. Pressure,... 

Further chapters cover in detail the characteristics and applications of galvanic anodes and of cathodic protection rectifiers, including specialized instruments for stray current protection and impressed current anodes. The fields of application discussed are buried pipelines storage tanks tank farms telephone, power and gas-pressurized cables ships harbor installations and the internal protection of water tanks and industrial plants. A separate chapter deals with the problems of high-tension effects on pipelines and cables. A study of costs and economic factors concludes the discussion. The appendix contains those tables and mathematical derivations which appeared appropriate for practical purposes and for rounding off the subject. 

The hydraulieally tensioned, radial-fit bolt (Figure 6-32) replaees the traditional turbine shaft eoupling bolt and is reusable. The main body of the bolt is threaded at eaeh end and has a slight taper on the eenter seetion, whieh engages with the similarly internally tapered sleeve and the two nuts. The bolt is taper-bored at eaeh end to aeeept the puller that is part of the hydraulie tensioning system. 

At present there is only one commercially available tissue adhesive with approved on-label indications for skin closure. 2-Octyl-cyanoacrylate (Dermabond, Ethicon, Inc., Somerville, NJ) is presently indicated for skin closure in wounds which are not under extreme tension. This tissue adhesive is approved for topical skin application only. It is not indicated for internal use. The material is useful in closing traumatic skin lacerations [4,5] after wounds have been thoroughly cleaned as well as for minimally invasive surgical incisions and even larger surgical incisions in elective cases. The cyanoacrylate is applied while the skin... 

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