The mantle

In use, a mantle of ice is frozen onto the outer surface of the thermometer weU. A common way to do this is to fiU the weU with cmshed dry ice until the mantle achieves a good thickness. Descriptions of the technique for doing this are given in several pubHcations and in manufacturers Hterature. The temperature of the water triple point is 0.01°C, or 273.16 K, by definition. In practice, that temperature can be realized in the ceU within 0.00015 K of the definition. In contrast, a bath of ice and water for producing the temperature 0°C is difficult to estabHsh with an accuracy better than 0.002°C. 

The bubble model (Kunii and Levenspiel, Fluidization Engineering, Wiley, New York, 1969 Fig. 17-14) assumes constant-sized bubbles (effective bubble size d ) rising through the suspension phase. Gas is transferred from the bubble void to the mantle and wake at... 

The outer shell of the earth, consisting of the upper mantle and the crust (Figure I4. lO), is formed of a number of rigid plates. These plates are 20 in number and are shown in Figure 14.1 I. Of these, six or seven are major plates, as can be seen in the map. The edges of these plates define their boundaries and the arrows indicate the direction of their movement. These plates contain the continents, oceans and mountains. They almost float on the partially molten rock and metal of the mantle. The outer shell, known as the lithosphere, is about 70 to 1,50 km thick. It has already moved great distances below the etirth s surface, ever since the earth was formed and is believed to be in slow and continuous motion all the time. The plates slide on the molten mantle and move about lO to 100 mm a year in the direction shown by the arrows. The movement of plates is believed to be the cause of continental drifts, the formation of ocean basins and mountains and also the consequent earthquakes and volcanic eruptions. 

The movement of these plates can ies with it continents, ocean basins and mountains. Scientists believe that convection currents are generated as a result of great heat within the earth, as illustrated in Figure 14. lO. Below the crust, the hot rocks and metal in liquid form rise to the crust, cool and sink into the mantle causing a turbulence through heat convection. The hot rocks become hardened at the surface of the mantle and push the crust which is part of the hug plates that are afloat the mantle. This movement of plates can cause the following ... 

When the plates move away from each other, the molten rock from the mantle fills the gaps between them to form oeean basins. 

If the plates pull down, they would sink into the mantle and melt to form ocean basins. Some of the molten rock of these plates may travel to the earth s surface through the crevice so formed due to heat convection and cause a volcano. 

Heating mantles. These consist of a flexible knitted fibre glass sheath which fits snugly around a flask and contains an electrical heating element which operates at black heat. The mantle may be supported in an aluminium case which stands on the bench, but for use with suspended vessels the mantle is supplied without a case. Electric power is supplied to the heating element through a control unit which may be either a continuously variable transformer or a thyristor controller, and so the operating temperature of the mantle can be smoothly adjusted... 

Fig. 3.1.2 The apparatus used in 1956 for the methanol extraction of Cypridina luciferin. The dried Cypridina (500 g) is extracted at a temperature lower than 40°C with refluxing methanol under reduced pressure for two days. The atmosphere inside the apparatus is completely replaced with hydrogen gas that was purified by its passing through a quartz tube containing red-heated copper fragments. The temperature of the mantle heater is adjusted, the system evacuated, and then all stopcocks are closed. The extraction with refluxing methanol continues for many hours without any further adjustment. From the author s 1957 notebook.

To avoid confusion with the shells of the shell model of the nucleus we shall refer to the layers of spherons by special names the mantle for the surface layer, and the outer core and inner core for the two other layers of a three-layer nucleus. 

Those subshells that occur (are occupied) with only the value 1 for the quantum number n contribute only to the outer layer of spherons (the mantle). 

Those subshells that occur with two values of n contribute to the mantle and the next inner layer, and so on. 

Thus for the neutron configuration ls22s2lp6ld103s22p62d10l/14lp18(lA 11/2)12 we assign Is2 to the inner core (2 neutrons), 2s2lp6ld10 to the outer core (18 neutrons), and the remainder (62 neutrons) to the mantle. 

The Assignment of Nucleons to Layers by Use of the Packing EquaMon.—Equation (1) has been applied in the assignment of neutrons to the mantle, outer core, inner core, and innermost core (for N very large), with the results shown in Figure 2. 

Fig. 2.—A diagram showing the ranges of values of the neutron number N in which successive uubsubshells of the mantle, outer core, and inner core are occupied by neutrons, as calculated with use of the packing equation. Observed values of spin and parity of odd N and odd Z nuclei are indicated by circles and squares.

The close-packed-spheron theory8 incorporates some of the features of the shell model, the alpha-particle model, and the liquid-drop model. Nuclei are considered to be close-packed aggregates of spherons (helicons, tritons, and dineutrons), arranged in spherical or ellipsoidal layers, which are called the mantle, the outer core, and the inner core. The assignment of spherons, and hence nucleons, to the layers is made in a straightforward way on... 

Let us consider the nucleus 44Ru3o. As discussed above, it is assigned 26 spherons, of which 22 are in the mantle and four in the core. From Fig. 3 we might assign 37 protons to the mantle and seven to the core. This assignment gives a mantle of 11 helions and 11 tritons and a core of three helions and one triton. 

Structures of this sort, with a mantle of helions and a core of neutrons, have minimum Coulomb energy. We may expect these structures to have the minimum neutron excess compatible with stability any more protons would be forced from the mantle into the core. In fact, 44RuB2 has the largest atomic number for which N — Z equals 8 for a stable isotope. 

Fig. 11. (Left) An outer core of 16 spherons surrounding an inner core of three, in a linear arrangement. (Right) The same core with a portion of the mantle of the elongated nucleus. (The difference in relative sizes of core and mantle spherons is exaggerated in this and some of the other figures.)...

I assume that in the process of fission both the mantle and the core undergo splitting. The core could split between the two middle rings, which would result in symmetric fission. 

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