Glass shaping

Fig. 3.7 Stages in the fabrication of a glass-ceramic, gas-tight, high current switch housing (a) the formed glass shape, (b) 18% Cr stainless steel (linear thermal expansivity 13 p.p.m. K ) flanges bonded to glass, (c) finished glass-ceramic component. The transparency of the disc (d) results from a very small grain size. (Courtesy of Advanced Ceramics Limited, UK.)...

A link is inserted and held in place with a wooden wedge made from a matchstick. The ends of the link are now softened in the flame and bent towards one another with tweezers. They are then joined and the worked glass shaped into a neat U, with a round carbon rod (Fig. 8.6e). 

Composition profiles are shown in Figure 14.12. Note the hour glass shape that asymptotes towards the vertical axes at the bottom of the column to meet the 400 ppm specification on the ethylbenzene purity. ... 

The first rotational state, J= 1, see 6.2.1, has a more complex shape imposed by the magnetic quantum numbers, M. The probability distribution function can be discussed in terms of two component shapes, which can be represented as a toroidal or ring-doughnut shape with its maximum probability in the x,y plane (horizontal) and, an hour-glass shape, with its maximum probability along the z axis, (vertical). (Recall that 6 is the angle between the normal to the x,y-plane (the z-axis) and the H—H axis.)... 

The hour-glass represents the Af = 0 state a dihydrogen molecule in this state is most likely (>64% probability) to be found within the ranges, 9 < 45° or > 135 . The direction of its horizontal component is equally probable in Notice that both the ring-doughnut and the hour-glass shapes occupy large volumes of space and considerable latitude is available in the values of 9. 

Fig. 6.6 Diagramatic representation of the probability distribution fiinction of the rotor. On the left, J = 0. On the right, J = 1, the solid lobe (the hour-glass shape) represents M= 0 and the wireframe (ring-doughnut) represents M= . ...

If the UCST and LCST curves are merged, the so-called hour glass shape is formed as can be seen in the... 

The effect of the variation of the molecular mass of the polymer on the equilibrium lines is comparable to the effect of gas concentration. This is due to the fact that small solvent molecules dissolve small molecules better than bigger ones. Thus, by increasing the molecular weight of the polymer, the immiscibility region is expanded. UCST and LCST move toward each other until they eventually merge to the hour glass shape. The effect of several variables on the location of the UCST and LCST is qualitatively illustrated in Figure 15.4. 

Figure 2. Demixing pressures for different concentrations a, b, c. Below each curve is the two-phase region. Depending upon the pressure, the system may display both UCST and LCST or hour-glass shaped region of immiscibility (A) only UCST (B) only LCST (C), or an island of immiscibility (D) in the temperature-composition plane. (See Figure 3).

The lost wax process of forming glass shapes has been used since the fifth century ce. Originally, the molten glass was poured into an outer mold made of beeswax, which could easily be removed. 

Type of data cloud points (hour glass shaped) ... 

The dilatometer should be made of borosilicate glass shape and dimensions are given in Fig. 6.2. The bulb of the dilatometer should have a volume of... 

---