Abstract: A computer-implemented method and system provide one or more primitive commands. Each primitive command when executed defines a shape of an object and accepts input data to specify one or more dimensions of the shape. When the dimensions are applied to the shape, a three-dimensional (3D) object that is a 3D part and/or a 3D feature is created. Input data is utilized by a selected primitive command to create a sketch as specified by a definition of the shape on a sketch plane that is automatically selected and to specify a transformation that creates the 3D object from the sketch.

Abstract: Automatically adding constraints between entities in a subject computer-aided design (CAD) model of a real-world object includes storing information regarding CAD model entities and related constraints in a computer database in which the CAD model entities belong to one or more components of the subject CAD model or other CAD models. The computer database is accessed to determine previously used constraints for at least one entity of a given component being added to the CAD model, and constraints are automatically added between at least one entity of the given component and another entity in the subject CAD model based on the previously used constraints.

Abstract: Automatically adding constraints between entities in a subject computer-aided design (CAD) model of a real-world object includes storing information regarding CAD model entities and related constraints in a computer database in which the CAD model entities belong to one or more components of the subject CAD model or other CAD models. The computer database is accessed to determine previously used constraints for at least one entity of a given component being added to the CAD model, and constraints are automatically added between at least one entity of the given component and another entity in the subject CAD model based on the previously used constraints.

Abstract: Creating an explicit feature used for construction of a computer-aided design model includes recognizing that model features form an implicit feature, presenting variations of the implicit feature, selecting one of the variations of the implicit feature, and creating the explicit feature. The explicit feature produces geometry that gives rise to the selected variation of the implicit feature. The computer-aided design model is constructed by generating the explicit feature after generating the model features that form the implicit feature.

Abstract: Creating an explicit feature used for construction of a computer-aided design model includes recognizing that model features form an implicit feature, presenting variations of the implicit feature, selecting one of the variations of the implicit feature, and creating the explicit feature. The explicit feature produces geometry that gives rise to the selected variation of the implicit feature. The computer-aided design model is constructed by generating the explicit feature after generating the model features that form the implicit feature.

Abstract: Automatically generating components of an object modeled in a three-dimensional modeling space by a computer aided design system includes positioning a plane in the three-dimensional modeling space to (i) logically subdivide the modeling space into a first division that includes an existing component and a second division in which a reproduction of the existing component is to be located and (ii) to define a reference geometry for creation of the reproduction of the existing component. A number of geometrically transformed components are computed by applying a series of different transformations to the existing component such that each transformed component has a different orientation. A reproduction of the existing component is constructed such that the existing component and the reproduction are symmetrical to each other with respect to the plane.

Abstract: An apparatus and process are disclosed for utilizing solar radiation and the energy contained therein for the carbothermic reduction of a metal oxide to a metal carbide. The apparatus comprises a reflective surface which collects and focuses solar radiation onto a focal mirror which consequentially reflects and focuses the solar light rays into a reaction chamber through a Fresnel lens and a transparent window provided on the chamber. The solar light rays are focused by the reflective surface focal mirror and Fresnel lens such that the energy absorbed by reactants in the reaction chamber is sufficient for the carbothermic reduction of the metal oxide.

Abstract: An apparatus and process are disclosed for utilizing solar radiation and the energy contained therein for the carbothermic reduction of a metal oxide to a metal carbide. The apparatus comprises a reflective surface which collects and focuses solar radiation onto a focal mirror which consequentially reflects and focuses the solar light rays into a reaction chamber through a Fresnel lens and a transparent window provided on the chamber. The solar light rays are focused by the reflective surface focal mirror and Fresnel lens such that the energy absorbed by reactants in the reaction chamber is sufficient for the carbothermic reduction of the metal oxide.

Abstract: Carbon fiber reinforced tantalum carbide composites are produced by vacuum infiltration of omni-weave carbon, e.g. three dimensional graphite, yarn preforms with an aqueous saturated solution containing tantalum fluoride and sucrose. Anhydrous ammonia is added under pressure, forming ammonium fluoride, which is removed by vacuum sublimation by application of heat. The resulting preform containing tantalum pentoxide and partially pyrolyzed sucrose is heated at high temperature and reduced pressure to decompose the sucrose to yield active carbon which reacts with the tantalum pentoxide to yield tantalum carbide and carbon monoxide.

Abstract: Carbon fiber reinforced tantalum carbide composites are produced by vacuum infiltration of omni-weave carbon, e.g. three dimensional graphite, yarn preforms with an aqueous saturated solution containing tantalum fluoride and sucrose. Anhydrous ammonia is added under pressure, forming ammonium fluoride, which is removed by vacuum sublimation by application of heat. The resulting preform containing tantalum pentoxide and partially pyrolyzed sucrose is heated at high temperature and reduced pressure to decompose the sucrose to yield active carbon which reacts with the tantalum pentoxide to yield tantalum carbide and carbon monoxide.