Spheres glass

Microspheres provide the lowest possible surface area to volume ratio. Glass microspheres are widely used. The chemical composition of glass beads for A glass is Si02, AI2O3, CaO, 

and K2O, and their diameters range from 30 pm to 750 pm. Their characteristics are refractive index = 1.51, density 2.48 g/cc, hardness 5.5 Moh s scale, thermal expansion coefficient 8.47 x 10 /°C from 20 °C to 300 °C, dielectric constant - of 12.2 at 1 Kh and 23 C. Glass spheres have been used in reflective applications, such as highway signs and markers since they were introduced in the mid 1960s. 

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Marlow and Rowell discuss the deviation from Eq. V-47 when electrostatic and hydrodynamic interactions between the particles must be considered [78]. In a suspension of glass spheres, beyond a volume fraction of 0.018, these interparticle forces cause nonlinearities in Eq. V-47, diminishing the induced potential E. 

In Figure 5.24 the predicted direct stress distributions for a glass-filled epoxy resin under unconstrained conditions for both pha.ses are shown. The material parameters used in this calculation are elasticity modulus and Poisson s ratio of (3.01 GPa, 0.35) for the epoxy matrix and (76.0 GPa, 0.21) for glass spheres, respectively. According to this result the position of maximum stress concentration is almost directly above the pole of the spherical particle. Therefore for a... 

Various other substances have also been used in tests. Robens, for example, with glass spheres 20 to 60 pm in diameter, obtained a BET area (taking = 16-2 A ) which was only 5 per cent higher than the... 

MicrobaUoons have been used for gap filling, where the spheres dampen sound or vibration in the stmcture. In the medical area, microbaUoons have been evaluated as a skin replacement for bum victims and phantom tissue for radiation studies. An important appHcation is in nitroglycerin-based explosives, in which microbaUoons permit a controUed sequential detonation not possible with glass spheres. 

Another polyolefin of interest is polystyrene, a clear, brittle plastic that, by itself, is rarely used in composites. However, several copolymers and alloys of polystyrene with acrylonitrile or butadiene have been used with fiber glass or glass spheres to form composites (7). 

Jackson and Calvert [Am. Inst. Chem. Eng. J., 12, 1075 (1966)] studied the collection of fine fuel-oil-mist particles in beds of V2-iu glass spheres, Raschig rings, and Berl and Intalox saddles. The mist had a mass median particle diameter of 6 Im and a standard deviation of 2.0. The collection efficiency as a function of particle size and gas... 

The reinforcing filler usually takes the form of fibres but particles (for example glass spheres) are also used. A wide range of amorphous and crystalline materials can be used as reinforcing fibres. These include glass, carbon, boron, and silica. In recent years, fibres have been produced from synthetic polymers-for example, Kevlar fibres (from aromatic polyamides) and PET fibres. The stress-strain behaviour of some typical fibres is shown in Fig. 3.2. 

Hasegawa and Sato Glass sphere pressurized C5H12 0.3-30 0.8-1.7 2.7-15 110-413... 

Experimental Work. Few experiments measuring the blast from exploding, gas-filled pressure vessels have been reported in the open literature. One was performed by Boyer et al. (1958). They measured the overpressure produced by the burst of a small, glass sphere which was pressurized with gas. 

The failure of systems with dispersed fillers (exemplified by polystyrene plus glass spheres with different treatment) was studied by subjecting specimens to deformation in the microscope field [255,256]. Where adhesion was good the cracks were observed to be formed near the glass sphere pole, in regions corresponding to the maximum deformation, where adhesion was poor, anywhere between the pole and the equator. It was discovered that microcracks began to... 

Kato (K3) measured so-called critical gas velocities corresponding to the complete suspension of solids, and presents a graphical correlation of the results for glass spheres (diameters from 0.074 to 0.295 mm), magnetite particles (particle size from 0.038 to 0.175 mm), and sand particles (particle size 0.147 to 0.295 mm). 

This design was closely followed in the experimental model and in the later instruments. The experimental model (October, 1940) had as test body a dumbbell of two thin-walled glass spheres 4 mm. in diameter sealed to a glass rod 6 mm. long. A silica fiber 8 fi in diameter was stretched between the prongs of a silica fork, and the glass dumbbell was cemented with shellac to the middle of the fiber, perpendicular to it. A plane glass mirror 2 mm. square was also cemented near the middle of the fiber. The suspension was balanced... 

Epstein, M. S. Velapoldl, R. A. Blackburn, D. Evaluation of Luminescent Glass Spheres as Calibration Standards for Micro-spectrofluorimetry National Bureau of Standards Gaithersburg, MD Annual Task Report to Food and Drug Administration, 1984, 1985, 1986 also, paper to be submitted. 

The aim of the work was the development of a technique to deposit enzyme LB films on the surface of small glass spheres and to test the enzymatic activity of such samples before and after thermal treatment. 

Borosilicate glass spheres with a diameter of 2 mm were used as substrates for the deposition. 

G. H. Medley, Jr., J. E. Hasten, R. L. Montgomery, I. D. Martindale, and J. R. Duda. Field application of lightweight, hollow-glass-sphere drilling fluid, y Petrol Technol, 49(11) 1209-1211, November 1997. 

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