General Dynamics

About: General Dynamics is a company organization based out in Fairfax, Virginia, United States. It is known for research contribution in the topics: Signal & Propellant. The organization has 5722 authors who have published 5819 publications receiving 85768 citations. The organization is also known as: GD & General Dynamics Corporation.

Transverse injection surface emitting laser

Abstract: A semiconductor laser for emitting light transverse to the direction of current injection. The laser is fabricated from a substrate having planar top and bottom surfaces and an aperture formed therebetween. An optical cavity, formed upon the substrate top surface and aligned with the aperture, has co-planar top and bottom surfaces with dielectric mirrors formed thereupon. Contacts are formed adjacent the optical cavity for conducting current through the optical cavity in a direction substantially parallel to the optical cavity top and bottom surfaces. Current confinement layers are disposed in intimate contact with the optical cavity for confining current flowing in the optical cavity along a predetermined path extending between the contacts.

Solution of Highly Constrained Optimal Control Problems Using Nonlinear Programing

Abstract: HIS paper considers the solution of highly constrained optimal control problems using the nonlinear programing method of Fiacco-McCormick.1 Several authors2'3 have successfully applied the technique to constrained optimal control problems of a limited scope. The present paper expands the theory to encompass a general mathematical model for trajectory optimization capable of directly handling six types of equality and inequality constraints. The user-oriented model is designed to facilitate the rapid set up of a wide range of different simulations and provides for the simultaneous optimization of design parameters and continuous control variables. Accurate and efficient methods of unconstrained function minimization and linear search required to implement the Fiacco-McCormick method are discussed. Contents The general mathematical model presented provides a flexible skeletal framework for describing a wide spectrum of complex optimal control problems in terms of problem-oriented functions. The model is capable of incorporating two classes of independent variables which are to be chosen to extremize some objective function. Independent variables which are functions of time are termed dynamic control variables and are designated by uk(t). Independent variables which are constant with respect to time are termed design variables, dp. Trajectory sectioning is a device commonly used to provide flexibility in modeling. It is a method of subdividing the time history of a trajectory simulation into parts relevant to the description of the simulation. A section is defined as any portion of the trajectory in which the mathematical model is of a given form and the state variables xt(t) are continuous functions of time. Section endpoints are chosen to coincide with points at which the differential equations of motion, the control model, or the trajectory constraints change form ; or at which the state variables experience a discontinuity. If the subscript) denotes the trajectory section, then the general optimal control problem is to

Multi-layer stitched blanket insulation

Abstract: A multi-layer blanket insulation adapted of use in an aerobrake intended to assist in the return of a space vehicle from a higher earth orbit to a low earth orbit for recovery and possible reuse. Between two face sheets of a cloth material highly resistant to elevated temperatures are interposed a layer of a flexible insulative material and a layer of non-porous foil. The insulation is stitched together into a predetermined pattern. A backside stiffener may be secured to the back face by a layer of a suitable cloth material.