Disc-shaped bodies

FIGURE 14J9 Log-log plot of wei it loss versus time for disc shaped Si powder green body made with different solvents and dried at different conditions (a) solvent-octanol, T = 200°C, Ni velocity 0.1 cm/sec (b) solvent-methanol, T = 80X , JV2 velocity 1.3 cm/ sec (c) solvent-acetcmitrile, T = 2TC N2 velodty 0 cm/sec. Takm from Castro et al. [25]. Reprinted by permission of the American Ceramic Society. 

The planets of our solar system probably formed from a disc-shaped cloud of hot gases, the remnants of a stellar supernova. Condensing vapours formed solids that coalesced into small bodies (planetesimals), and accretion of these built the dense inner planets (Mercury to Mars). The larger outer planets, being more distant from the sun, are composed of lower-density gases, which condensed at much cooler temperatures. 

Also within the cytoplasm and visible in the electron microscope and separable by appropriate centrifugation procedures, is a system of disc-shaped, membrane-bound channels, three to twelve in number, stacked together to form the Golgi bodies, so called after an Italian microscopist of the late nineteenth century. These Golgi bodies are especially well developed in cells which are specialized for the production and secretion of substances like hormones, and they may be involved in packaging substances prior to extrusion from the cell. 

Figure 4.45. Schematic diagram of spectro-photoelectrochemical reflection cell with slab window (1) metallic supporting frame (2) glass body of cell (3) CaF2 window (4) outer glass tube (5) thin internal tube holding working electrode (6) disc-shaped working electrode (7) micrometer gauge (8) Teflon holder (9) reference electrode (10) Pt counter electrode (11,12) plane mirrors. Reprinted, by permission, from J. Klima, K. Kratochvilova, and J. Ludvik, J, Electroanal. Chem. 427, 57 (1997), p. 58, Fig. 1. Copyright 1997 Elsevier Science S.A.

A crystal or pressed pellets of an insoluble salt can act as ion sensitive elements operating in much the same way as the salt dispersed in an inert matrix. The crystal is precision ground into a disc shape and fixed onto an electrode body. The manufacturing process is closety controlled to avoid the crystal developing an internal crack or leak. The crystal should also not have high resistance. Examples can be cited of the lanthanum fluoride electrode (measure fluoride) and silver chloride electrode (measures chloride). 

Human blood cells have a biconcave disc shape with an average diameter of 8.1 pm. They are roughly 2 pm thick at the outer edges and 1-pm thick in their center [16]. In a typical person, red blood cells (RBCs) have a coefficient of variation of approximately 11% [16]. Thus, the size distribution in this colloidal population can be considered relatively uniform. The outer surface of a red hlood cell is composed of a phospholipid bilayer membrane [16] similar to that of most eukaryotic cells. However, unlike most cells, RBCs do not divide or reproduce themselves. They are fabricated as individual particles elsewhere within the body [16] and are, thus, truly colloidal in nature. The colloidal nature of RBCs and their unique shape motivated us to fabricate metallic colloidal particles using them as templates. Several potential commercial applications are envisioned [1—10]. 

The properties of mixtures of phases depend on the distribution of the components. The concept of connectivity is useful in classifying different types of mixture. The basis of this concept is that any phase in a mixture may be self-connected in zero, one, two or three dimensions. Thus randomly dispersed and separated particles have a connectivity of 0 while the medium surrounding them has a connectivity of 3. A disc containing a rod-shaped phase extending between its major surfaces has a connectivity of 1 with respect to the rods and of 3 with respect to the intervening phase. A mixture consisting of a stack of plates of two different phases extending over the entire area of the body has a... 

The shape of the measuring body may vary. A simple form is that of a flat disc (see fig. 3.69). If the containing vessel rotates, a torque is exerted on the disc. It consists of a contribution from the viscous friction by the adjacent fluids above and below the disc and from the interface. For an air-liquid interface and the limits that 0/7 77 and a h. R, the torque T exerted on a rotating disc is given by Goodrich and Chatteijee. ... 

Stingrays are often mistaken for Manta Rays. Manta Rays are larger, reaching a much greater body width and have a diamond-shaped disc. Manta Rays lack a stinging barb are therefore relatively harmless. Their head also has odd fins that guide plankton into the mouth. 

Also Tablet. A compressed agglomerate made of particulate solids, specifically, in pharmacy, a small compact of a medicated particulate formulation usually in the shape of a disc or a flat polyhedral body. (See also briquette.) The process of forming tablettes. 

The main concept in this design was based on the already existing low-friction principle in the TJR field, using a metal alloy articulating with UHMWPE. The SB Charite artificial disc is made of three components, two of which are metal endplates that attach to the upper and lower vertebral body endplates by means of anchor teeth, and an UHMWPE sliding core that moves in between these two metal endplates. The endplates of the first two models of the SB Charite (1 and 11) were manufactured from 1-mm thick stainless steel. Specifically, the ones in model Type 1 were round and later evolved to an oval shape in model Type 11 (Buttner-Janz, Hochschuler, and McAfee 2003). 

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