structure(redirected from radiopaque structure)
Also found in: Dictionary, Thesaurus, Medical, Legal, Financial.
- any arrangement of elements into a definite pattern. e.g. any institutionalized social arrangements (ROLES, ORGANIZATIONS etc.) e.g. the ‘educational’ or ‘occupational structure’ (see also SOCIAL STRUCTURE. STRUCTURAL-FUNCTIONALISM).
- the rules (or ‘deep structure’) underlying and responsible for the production of a surface structure (especially structures analogous to GRAMMAR) (see also LINGUISTICS, LÉVISTRAUSS). For GIDDENS (1984), for example, 'structure’ in this latter sense refers to ‘rules and resources’, implicated in the reproduction of social systems (see also STRUCTURATION, STRUCTURATION THEORY). The distinction (sense 1 and 2) drawn between 'surface’ and ‘deep structures’ is also an important one in STRUCTURALISM (senses 3 and 5).
A compromise between theories of structure and theories of meaning has often been attempted by social theorists. In the 1960s P. L. Berger and associates proposed a ‘dialectical’ theory of the 'social construction of reality’, in which 'social structure is not characterizable as a thing able to stand on its own, apart from the human activity that produced it’, but, once created, ‘is encountered by the individual (both) as an alien facticity (and) … as a coercive instrumentality’ (Berger and Pullberg, 1966). A humanly constructed reality only comes to take on the appearance of having been constructed by some external, non-human, force. GIDDENS’ more recent proposal that 'structures’ can always in principle be examined in terms of their structuration ‘as a series of reproduced practices’ (Giddens, 1976b), and that structures are ‘both constraining and enabling’, is another example of an approach offering a compromise between theories of action and theories of structure (see DUALITY OF STRUCTURE, STRUCTURATION, STRUCTURATION THEORY). see also STRUCTURE AND AGENCY.
the totality of stable relationships in an object that ensure its integrity and self-identity, that is, the preservation of basic properties despite various external and internal changes.
In a broader, looser sense, the concept of structure has been used in science and philosophy at least since the Middle Ages and has served as a means of defining the concept of form—meant as the structure or the organization of content. In its narrow sense, the concept of structure was first developed in chemistry, in the 19th century, with the emerging theory of the chemical structure of matter.
In 1890 the Austrian psychologist C. von Ehrenfels described what he called gestalt properties—perceptual structures that refer to the perceived object as a whole and that cannot be explained in terms of the properties of separate elements; such are, for example, the properties of a chord in music or of a melody that are preserved in transposition. This formulation gave impetus to research on the independent role of psychostructure, to which Gestalt psychology made a significant contribution. In the 20th century, the analysis of structural relationships and connections has become a prime concern in the study of language, of ethnic communities, of literature and art, and of culture as a whole. As a result, specific methods have been adopted in the study of different types of structure, as for example in structuralism, structural linguistics, structural literary analysis, and structural-functional analysis.
In modern science, the concept of structure is usually related to the concepts of system and organization. While there is no common agreement on the interrelations of these concepts, in most cases the concept of system is regarded as the broadest. System represents all the manifestations of a given complex object, including its elements and the arrangement of its parts as well as connections and functions; structure is only that which remains stable and relatively unchanged through various transformations of the system; and organization includes both the structural and the dynamic characteristics of a system that ensure its purposeful operation.
Given the essential role of structural links and relations, the study of structure has acquired major importance in a whole series of scientific problems. Not infrequently, this leads to an incorrect juxtaposition between structure and some other feature of an object—most often, its history—and thus to a virtual abso-lutization of a one-sided approach to the object. In reality, however, the structural and the historical approach are not mutually exclusive, since each is oriented to the study of connections of a particular type. On the one hand, then, it is perfectly legitimate to posit the question of independent study, for specific aims, of either the structure of an object (as in various ecological, linguistic, and sociological problems) or its history (where the processes of development of an object are the immediate subject of research). On the other hand, however, there is no barrier in principle between structural and historical research: at some point the study of structure inevitably makes it necessary to understand the laws governing structural changes as well—namely, the history of a given structure; and the study of history becomes strictly scientific only insofar as it succeeds in revealing the structure of a developing object and the structure of the developmental process itself. K. Marx’ study of the historical laws of society exemplified precisely such an organic relationship between the historical and the structural approach.
Dialectical materialism regards structure as a category that, while important for modern knowledge, can reveal its heuristic meaning only in close association with the entire system of dialectical categories.
REFERENCESSviderskii, V. I. O dialektike elementov i struktury v ob”ektivnom mire i vpoznanii. Moscow, 1962.
Val’t, L. O. “Sootnoshenie struktury i elementov.” Voprosy filosofii, 1963, no. 5.
Ovchinnikov, N. F. “Struktura i simmetriia.” In Sistemnye issledovaniia: Ezhegodnik—1969. Moscow, 1969.
Blauberg, I. V., and E. G. Iudin. Stanovlenie i sushchnost’ sistemnogo podkhoda. Moscow, 1973. Chapter 4, sec. 3.
N. F. OVCHINNIKOV and E. G. IUDIN
An arrangement of designed components that provides strength and stiffness to a built artifact such as a building, bridge, dam, automobile, airplane, or missile. The artifact itself is often referred to as a structure, even though its primary function is not to support but, for example, to house people, contain water, or transport goods. See Airplane, Automobile, Bridge, Buildings, Dam
The primary requirements for structures are safety, strength, economy, stiffness, durability, robustness, esthetics, and ductility. The safety of the structure is paramount, and it is achieved by adhering to rules of design contained in standards and codes, as well as in exercising strict quality control over all phases of planning, design, and construction. The structure is designed to be strong enough to support loads due to its own weight, to human activity, and to the environment (such as wind, snow, earthquakes, ice, or floods). The ability to support loads during its intended lifetime ensures that the rate of failure is insignificant for practical purposes. The design should provide an economical structure within the constraints of all other requirements. The structure is designed to be stiff so that under everyday conditions of loading and usage it will not deflect or vibrate to an extent that is annoying to the occupants or detrimental to its function. The materials and details of construction have durability, such that the structure will not corrode, deteriorate, or break under the effects of weathering and normal usage during its lifetime. A structure should be robust enough to withstand intentional or unintentional misuse (for example, fire, gas explosion, or collision with a vehicle) without totally collapsing. A structural design takes into consideration the community's esthetic sensibilities. Ductility is necessary to absorb the energy imparted to the structure from dynamic loads such as earthquakes and blasts. See Construction engineering, Engineering design
Common structural materials are wood, masonry, steel, reinforced concrete, aluminum, and fiber-reinforced composites. Structures are classified into the categories of frames, plates, and shells, frequently incorporating combinations of these. Frames consist of “stick” members arranged to form the skeleton on which the remainder of the structure is placed. Plated structures include roof and floor slabs, vertical shear walls in a multistory building, or girders in a bridge. Shells are often used as water or gas containers, in roofs of arenas, or in vehicles that transport gases and liquids. The connections between the various elements of a structure are made by bolting, welding or riveting. See Composite material, Concrete, Structural materials