Hollow spheres thick-walled

As a second model we may consider a hollow sphere, with wall thickness t. A similar calculation leads to the following results ... 

A unique and considerably more elaborate multiaxial test employs a thick-walled hollow sphere test specimen which may be pressurized internally or externally with a nearly incompressible liquid. Figure 20 illustrates the essential features of the test device as described by Bennet and Anderson (5). The specimen is prepared by casting propellant in a mold fitted with a sand-poly (vinyl alcohol) mandrel inside the sphere which may be removed easily after curing. A constant displacement rate instrument drives the piston to pressurize the chamber and apply large deformations. The piston s total displacement volume is transferred to... 

Recently, Kinra and Ker 137) published data of the shear modulus of syntactic foams consisting of hollow glass spheres in a poly(methyl methacrylate) matrix. The glass spheres had a mean radius of 45 pm and a wall thickness of 1.2 pm. Reliable values are known for the shear modulus of the polymer G0, the shear modulus of glass Gs, and Poisson s ratio of the polymer G0 = 1120 MPa, Gs = 2800 MPa, and v0 = 0.35. Using these values, the upper curve 1 of Fig. 24 was calculated by Nielsen for the modulus of the foam as a function of the volume fraction of hollow spheres. These calculated values are, however, too high compared with the experimental values reported by Kinra and Ker. 

This is not surprising since the calculations are based on a perfectly uniform wall thickness of 1.2 pm for all spheres. In actual practice, as it was mentioned above, there are frequently thin spots in the glass shells, and some spheres have shells thinner than the mean value. Since the apparent modulus of the hollow spheres depends... 

Fig. 1.3 Steady, one dimensional conduction, a Temperature profile in a flat plate of thickness <5 = r2 — r, b Temperature profile in a hollow cylinder (tube wall) or hollow sphere of inner radius r and outer radius r2...

AgCLAD TW and Filament 32 - a thick-walled spheres and fiber coated with silver, respectively Metahte SG, CG, SF-20 - light hollow glass spheres coated with silver Toho Rayon Co., Ltd, Tokyo, Japan... 

The system consists of hollow spheres made up from the polymer poly-n-butylcyanoacrylate which are filled with a triglyceride oil component and dispersed in an aqueous phase in presence of a surfactant. While the capsule walls are only a few nanometers thick, the capsule radius varies between 100 and 200 nm. A cross-... 

Features Strong, hard, inert, thick-walled hollow spheres Properties Lt. gray spheres 1.3 p avg. particle size 7+ Hegman grind 0.01% retained on 325 mesh sp.gr. 2.3 g/cc (D153) bulking value 19.2 Ib/gal soften, pt. 1200 C pH 4.0-7.0 compr. str. > 60,000 psi hardness (Mohs) 7 99.4% spheres Zeeospheres G-400 [Zeelan]... 

This can readily be seen, on account of the relatively large thickness of the walls in these objects, with the hollow spheres formed from drops of the gelatin (positive)-nucleic add (negative) complex coacervate when indifferent salts are added to the medium. Fig. 23d. 

The G -h A + n shell of the objects depicted in Fig. 25f (p. 458) also give invagination after gela-tinization f —> g which again disappears after addition of distilled water. This is similarly the case with the gelatinized relatively thick walled G + N hollow spheres of Fig. 23 (d —e), see pag. 456. 

Hollow glass spheres (microballoons) have densities as low as 9 Ib/ft. For a given external diameter (normally 10-500 pm), the density is a function of the wall thickness, which, in turn, affects the mechanical strength of the hollow spheres. 

Another example of the piezoelectric composite stmctures either with 3-0 or 3-1 connectivity is the miniature piezoelectric hollow sphere transducer (Alkoy et al. 1997 Fernandez et al. 1996 Meyer et al. 1994). Technique allowing for the manufacturing of the extremely small thin-walled bubbles (1-6 mm in diameter and 80 xm wall thickness) from PZT slurry has been developed. Such bubbles could be electroded and poled either radially (3-0 coimectivity) or cylindrically (3-1 connectivity) if the hole is drilled through the bubble (Fig. 7.30). Composite stracture vibrates in radial (breathing) or in thickness mode. Effective hydrostatic piezoelectric coefficient as well as significantly enhanced with... 

FIGURE 12.6 (a) Illustration of the preparation of mesoporous Au-mesoporous carbon and silica capsules using glucose as carbon source. (From Kim, J. Y. et al., Chemical Communications, 790, 2003.) (b) TEM images of Au nanoparticles in microporous carbon hollow spheres prepared from dopamine as the carbon precursor. The carbon spheres were as large as the Au-silica template spheres, approximately 400 nm in diameter, and the carbon walls were A nm thick. (From Liu, R. et al., Angewandte Chemie-Intemational Edition, 50, 6799, 2011.)... 

Different phases of copper sulfide including covellite (CuS), digenite (Cui gS) and chalcocite (CU2S) were prepared as nanoscaled hollow spheres by reaction at the liquid-to-liquid phase boundary of a w/o-microemul-sion. The hollow spheres showed an outer diameter of 32-36 nm, a wall thickness of 8-12 nm and an inner cavity of 8-16 nm in diameter. The phase control was shown to be possible by adjusting the experimental conditions such as type and concentration of the copper precursor and concentration of ammonia inside of the micelle. 

Figure lb). These results indicate that the wall thickness depends on promoter of coating process. On the other hand, the spherical particles include larger size of particles than the hollow spheres shown in Figure Ic. 

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