(redirected from contact surface)
Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.
Related to contact surface: Surface 2


1. Geometry
a. the complete boundary of a solid figure
b. a continuous two-dimensional configuration
a. the uppermost level of the land or sea
b. (as modifier): surface transportation



a fundamental geometric concept with different meanings in different branches of geometry.

(1) A high-school geometry course considers planes, polyhedrons, and some curved surfaces. Each of the curved surfaces is defined in a special way— most often as a set of points that satisfy certain conditions. For example, the surface of a sphere is the set of points at a specified distance from a given point. The concept of a surface is merely exemplified rather than defined. Thus, a surface is said to be the boundary of a solid or the trace of a moving curve.

(2) The mathematically rigorous definition of a surface is based on the concepts of topology. The principal concept here is that of a simple surface, which may be represented as a part of a plane that is subject to continuous deformation— that is, to continuous extension, compression, or bending. More precisely, a simple surface is the image of the interior of a square under a homeomorphic, that is, a one-to-one and bicontinuous, mapping. This definition can be expressed analytically as follows. Introduce Cartesian coordinates u, v in the plane and x, y, z in space. Let S be the (open) square whose points have coordinates satisfying the inequalities 0 < u < 1 and 0 < v < 1. A simple surface is the homeomorphic image in space of the square Sʹ. The surface is given by means of formulas x = Φ (u, v), y = ψ(u, v), z = x(u, v), which are called its parametric equations. For different points (u, v) and (u ʹ, vʹ) the corresponding points (x, y, z) and (xʹ, yʹ, zʹ) must be different, and the functions Φ(u, v), ψ(u, v), and x(u, v) must be continuous. The hemisphere is an example of a simple surface. The sphere, however, is not a simple surface. Further generalization of the concept of a surface is consequently necessary. If a neighborhood of each point of a surface is a simple surface, the surface is said to be regular. From the standpoint of topological structure, surfaces as twodimensional manifolds are divided into several types, such as closed and open surfaces and orientable and nonorientable surfaces.

The surfaces investigated in differential geometry usually obey conditions associated with the possibility of using the methods of the differential calculus. These are usually smoothness conditions, such as the existence of a tangent plane or of curvature at each point of the surface. These requirements mean that the functions Φ(u, v), ψ(u, v), and x (u, v) are assumed to be once, twice, three times, or, in some problems, infinitely differentiable or even analytic. Moreover, it is required that at each point at least one of the determinants

be nonzero.

In analytic and algebraic geometry, a surface is defined as a set of points whose coordinates satisfy an equation of the form

(*) Φ(x, y, z) = 0

Thus, a given surface may or may not have a graphic geometric image. In this case, in order to preserve generality, we speak of imaginary surfaces. For example, the equation

X2 + y2 + z2 + 1 = 0

defines an imaginary sphere, although real space contains no point with coordinates satisfying this equation. If the function Φ(x, y, z) is continuous at some point and has at this point continuous partial derivatives ∂Φ/ ∂x, ∂Φ/ ∂y, ∂Φ/∂z, at least one of which does not vanish, then in the neighborhood of this point the surface defined by equation (*) will be a regular surface.


The outer part (skin with a thickness of zero) of a body; can apply to structures, to micrometer-sized particles, or to extended-surface zeolites.
A subset of three-space consisting of those points whose cartesian coordinates x, y, and z satisfy equations of the form x = ƒ(u, v), y = g (u, v), z = h (u, v), where ƒ, g, and h are differentiable real-valued functions of two parameters u and v which take real values and vary freely in some domain.


(1) See Surface tablet, Surface Book, Surface Studio and PixelSense.

(2) In CAD, the external geometry of an object. Surfaces are generally required for NC (numerical control) modeling rather than wireframe or solids.
References in periodicals archive ?
NASDAQ: PURE ), creator of the patented silver dihydrogen citrate (SDC) antimicrobial, today announced that research conducted by scientists at the University of Arkansas demonstrates the superior efficacy of PURE Hard Surface over quaternary ammonia for cleaning and decontaminating food contact surfaces.
To evaluate it, we define a metric point, namely PRI, indicating whether the palm of object would rotate with respect to the contact surface [S.
While the area of the iron chills' contact surface practically had no influence on the solidification time of the test casting, the volume, representing heat capacity of the chill, was the only significant factor (Fig.
PURE Hard Surface provides an unparalleled combination of safety, efficacy and efficiency with its dual function as both a disinfectant and a food contact surface sanitizer.
Their research indicates that UV polymerization may effectively bind the enzymes, with retained activity, to a food contact surface to act as bioactive packaging.
IV-7 Ultimate Germ Defense for Food Contact Surfaces[TM] harnesses the same broad-spectrum disinfecting power as Ultimate Germ Defense combined with registration by the US EPA for food contact surface sanitization while maintaining the EPA Category IV rating.
Also included are fabrication criteria to eliminate or reduce the number of cracks and crevices where product residues may lurk, sufficiently large radii in internal angles to prevent soils from being retained, product contact surface textures that facilitate the removal of soils, and the ability to easily disassemble the equipment for cleaning and inspection as necessary.
Key statement: The windshield molding incorporates an extruded strip of elastomeric material, such as Alcryn or Raupren melt-processible rubber, at the contact surface of the molding where a windshield primer is applied to the glass prior to the installation of the molding.
Environmental Protection Agency (EPA) registration for its SDC-based disinfectant and food contact surface sanitizer.
Responding to customer feedback, InstantGlaze II is a lower-viscosity, softer material that squeezes down during application to increase contact surface with the window, while offering the same green strength, reduced hold times and increased efficiency of InstantGlaze I, according to the manufacturer.