Spherical conduction

In [43], the carbon cage was represented as a classical infinitesimally thin spherical conducting sphere. Methods of classical physics were used to determine the dipole polarizability ad co) of the sphere. Accordingly,... 

The potential energy of an bn (point chargee) in the field of a spherical conducting particle carrying i elementary charges is... 

Fig. 9. Size dependence of electron affinities (EA) of vanadium clusters. The abscissa is proportional to the reciprocal of the cluster radius. The solid line shows the predicted values by the spherical conducting drop model BA = Woa — c /(2fl), where IVoo is the work function of a bulk metal. The model well explains the experimental data above n 10. ...

Fig. 11 The Induced current pattern on the spherical conducting shell due to the plasma tilt. Ref. [22]...

Usually, a composite filled with large specific ratio fibers or flakes has a lower percolation threshold than that filled with spherical conductive particles. The fillers with a high aspect ratio may also increase the tendency to form the co-continuous phases in polymer blend matrices [10]. These morphology-property relationships imply that if the conductive filler is preferential, or even totally localized in the minor phase or its surface (a-polymer) of a polymer blend, and the conductive filler/a-polymer blend is elongated or oriented to form conductive in situ microfibrils in the polymer matrix ([3-polymer), the composite obtained may have high conductivity (construction of 3D conductive in situ microfiber... 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

The conductivity of a dilute emulsion can be treated by classic theory (see Maxwell [6]) assuming spherical droplets... 

The reaction vessel is situated inside a metal of high themial conductivity having a cylindrical, spherical, or other shape which serves as the calorimetric medium. Silver is the most suitable material because of its high themial conductivity, but copper is most frequently used. 

Figure 5 shows conduction heat transfer as a function of the projected radius of a 6-mm diameter sphere. Assuming an accommodation coefficient of 0.8, h 0) = 3370 W/(m -K) the average coefficient for the entire sphere is 72 W/(m -K). This variation in heat transfer over the spherical surface causes extreme non-uniformities in local vaporization rates and if contact time is too long, wet spherical surface near the contact point dries. The temperature profile penetrates the sphere and it becomes a continuum to which Fourier s law of nonsteady-state conduction appfies. 

However, conductive elastomers have only ca <10 of the conductivity of soHd metals. Also, the contact resistance of elastomers changes with time when they are compressed. Therefore, elastomers are not used where significant currents must be carried or when low or stable resistance is required. Typical apphcations, which require a high density of contacts and easy disassembly for servicing, include connection between Hquid crystal display panels (see Liquid crystals) and between printed circuit boards in watches. Another type of elastomeric contact has a nonconducting silicone mbber core around which is wrapped metalized contacts that are separated from each other by insulating areas (25). A newer material has closely spaced strings of small spherical metal particles in contact, or fine soHd wires, which are oriented in the elastomer so that electrical conduction occurs only in the Z direction (26). 

One-Dimensional Conduction Many heat-condrrction problems may be formrrlated into a one-dimensional or pserrdo-one-dimensional form in which only one space variable is involved. Forms of the condrrction eqrration for rectangrrlar, cylindrical, and spherical coordinates are, respectively,... 

Tests were conducted using an approximately 30-cm-diameter, 80-/rm-thick polycarbonate film with brass backing plate. A 50-mm-diameter spherical discharge electrode was used to initiate discharge of the charged film... 

Let us first consider the role of electrostatic forces. To do this, we will start with the simplest case of a spherical, uniformly charged, dielectric particle on a grounded, conducting planar substrate. 

The force of attraction, calculated from Coulomb s law, for a uniformly charged, spherical, particle in contact with a grounded, conducting substrate is simply... 

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