Public sphere

Examples of Public sphere in the following topics:

• Public Sphere and Civil Society

  • The public sphere is composed of voluntary associations that promote social capital and social cohesion while enhancing democracy.
  • The study of the public sphere centers on the idea of participatory democracy, and how public opinion becomes political action.
  • The basic belief in public sphere theory is that political action is steered by the public sphere and that the only legitimate governments are those that listen to the public sphere.
  • "Democratic governance rests on the capacity of and opportunity for citizens to engage in enlightened debate. " Much of the debate over the public sphere involves what is the basic theoretical structure of the public sphere, how information is deliberated in the public sphere, and what influence the public sphere has over society.
  • Voluntary associations, such as Elks Clubs, make up the public sphere.

• The Family Economy: Women and Children

  • "Separate spheres" refers to an ideology that defines and prescribes different realms for women and men.
  • The notion of separate spheres dictates that men, based primarily on their biological makeup as well as on the will of God, inhabit the public sphere—the world of politics, economy, commerce, and law.
  • In Politics, Aristotle described two separate spheres in Greek society: the home (oikos) and the city (polis).
  • Women were confined to the private realm of the oikos while men occupied the public sphere of the polis.
  • The publication also equated womanhood with motherhood and with being a wife, declaring that the "perfection of womanhood (...) is the wife and mother."

• Problems

  • Consider a sphere of ionized hydrogen plamsa that is undergoing spherical gravitational collapse.
  • The sphere cools by emission of bremsstrahlung radiation in its interior.
  • At $t=t_0$ the sphere is optically thin.
  • What is the total luminosity of the sphere as a function of $M_0, R(t)$ and $T_0$while the sphere is optically thin?
  • Give an implicit relation in terms of $R(t)$ for the time $t_1$ when the sphere becomes optically thick.

• Crystal Structure: Packing Spheres

  • Within a crystalline material, each atom can be thought of as a sphere.
  • These spheres are packed into unit cells.
  • Each sphere that participates in a crystal structure has a coordination number, which corresponds to the number of spheres within the crystalline structure that touch the sphere that is being evaluated.
  • For a sphere in the interior of a crystal lattice, the number of spheres contacting the sphere that is being evaluated is known as the bulk coordination number.
  • For a sphere at the surface of a crystal, the number of spheres contacting the sphere being evaluated is known as the surface coordination number.

• B.5 Chapter 5

  • Consider a sphere of ionized hydrogen plasma that is undergoing spherical gravitational collapse.
  • The sphere cools by emission of bremsstrahlung radiation in its interior.
  • At $t=t_0$ the sphere is optically thin.
  • What is the total luminosity of the sphere as a function of $M_0, R(t)$ and $T_0$ while the sphere is optically thin?
  • Give an implicit relation in terms of $R(t)$$t_1$ for the time $t_1$ when the sphere becomes optically thick.

• Gravitational Attraction of Spherical Bodies: A Uniform Sphere

  • For highly symmetric shapes such as spheres or spherical shells, finding this point is simple.
  • The contribution of all shells of the sphere at a radius (or distance) greater than $d$ from the sphere's center-of-mass can be ignored (see above corollary of the Shell Theorem).
  • Only the mass of the sphere within the desired radius $M_{sphere inside $d$) is relevant, and can be considered as a point mass at the center of the sphere.
  • That is, the sphere's mass is uniformly distributed.)
  • The surface area of a thin slice of the sphere is shown in color.

• Van de Graff Generators

  • One of these pulleys is surrounded by a hollow metal sphere.
  • Two electrodes are positioned near the bottom of the lower pulley and inside the sphere, over the upper pulley.
  • One comb is connected to the sphere, and another is connected to the ground.
  • The sphere acts as a Faraday shield, shielding the upper roller and comb from the electric field produced by charges on the outside of the sphere.
  • Final potential is proportional to the size of the sphere and its distance from the ground.

• Crystal Structure: Closest Packing

  • Imagine a single layer of spheres packed into the bottom of a unit cell.
  • Spheres in one layer align to fit in the hollows formed in the previous layer.
  • The third layer of spheres does not align with the first layer.
  • A CCP arrangement has a total of 4 spheres per unit cell and an HCP arrangement has 8 spheres per unit cell.
  • In order to find this, the volume of the spheres needs to be divided by the total volume (including empty spaces) occupied by the packed spheres.

• Poincaré Sphere

  • This result shows that the Stoke's parameters live on a sphere of radius $r\leq s_0$ where the extent of polarization $\Pi=r/s_0$.
  • This sphere of polarization is known as the Poincare sphere (Fig.2.1) and the location of the polarization on the sphere is related to the orientation of the polarization ellipse in Fig.2.1.
  • The two angles defined in Fig.2.1 related to the latitude ($2\chi$) and longitude ($2\psi$) of the polarization vector $(s_1,s_2,s_3)$ on the Poincare sphere.

• Limiting Effects of Diffusion on Size and Development

  • Consider a cell shaped like a perfect sphere: it has a surface area of 4πr2, and a volume of (4/3)πr3.
  • The larger the size of the sphere, or animal, the less surface area for diffusion it possesses.
  • The image illustrates the comparison of spheres of one to one thousand volume units.
  • The surface-to-volume ratio of a sphere decreases as the sphere gets bigger.
  • The surface area of a sphere is 4πr2 and it has a volume of (4/3)πr3 which makes the surface-to-volume ratio 3/r.