Showing papers by "RAND Corporation published in 1970"

Inelastic Analysis of a Unidirectional Composite Subjected to Transverse Normal Loading

Abstract: Composite material behavior is divisible into three distinct re gimes, linear elastic response up to the elastic limit, inelastic be havior beyond the elastic limit and up to that point at which first failure occurs locally, and subsequent crack propagation and total composite failure. The first regime has been thoroughly explored in previous investigations, while the second is the main topic of the present paper. The third is briefly discussed and is a subject under investigation.Utilizing a finite element analysis, numerical results are obtained for composite behavior beyond the elastic limit and up to first failure. Examples representative of several actual material systems are presented and discussed in detail.Results indicate that extensive local yielding and redistribution of stresses can occur in a composite with very little indication of such behavior being apparent by observation of the total stress- strain response of the composite alone. Thus, the establishment and interpretation of design crit...

Transient scattering from conducting cylinders

Abstract: A method for determining the fields scattered by arbitrarily shaped cylindrical conducting structures with a transient incident wave is described. The transient scattering problem is reduced to the solution of a time domain integral equation which in turn is solved directly in the time domain by means of a digital computer. The approximate electromagnetic impulse response for a number of cylindrical scatterers is calculated using this method.

Speed command and throttle control system for aircraft

Abstract: Aircraft control apparatus for providing pitch guidance to the pilot during the takeoff acceleration phase between rotation airspeed and steady climbing speed in accordance with Federal Airworthiness Standards for takeoff safety speeds. The steady climbing target speed is determined from computed values of actual coefficient of lift of the aircraft compared to a reference value of coefficient of lift which is programmed in accordance with the number of operating engines, existing thrust to weight ratio, flap position, and leading edge slat extension. The pitch guidance is derived from a control equation which generates a regulating signal for driving the pitch command pointer of an attitude flight director display. Pitch guidance is provided for the pushover acceleration mode during which the aircraft''s takeoff flap-slat configuration is retracted and the aircraft is stabilized on a new climb path at a preset airspeed. Pitch guidance is also provided for a missed approach procedure. Further provision is made for the automatic or manual control of engine throttles to maintain an optimum thrust condition or to maintain a pilot set airspeed, including override means whereby a minimum safe speed based on flap position and computed gross weight will override the selected speed if it is below the computed minimum. An additional override is provided to inhibit pilot selection of airspeeds which are above structural limitations of the flaps. The system requires speed control parameters which are computed by apparatus which provides a measure of the angle of attack and coefficient of lift of an aircraft without external probes or vanes, which measure is derived from computations involving measurements of aircraft longitudinal acceleration, normal acceleration, vertical speed, calibrated airspeed, Mach number, and positions of the movable aerodynamic surfaces which affect the coefficient of lift of an airplane. Supplementary outputs of the computer are signals proportional to acceleration along the flight path, thrust over weight ratio, gross weight of the airplane, potential flight path angle of the airplane, and actual flight path angle.

Multilayer printed circuit electrical interconnection device

Abstract: A METHOD AND APPARATUS FOR ESTABLISHING INTERCONNECTIONS BETWEEN CONDUCTIVE LAYERS IN MULTILAYER PRINTED CIRCIUT ASSEMBLY WHEREIN A SOLDER COATED COMPRESSION TYPE COIL SPRING IS INSERTED INTO AN APERTURE IN AN INSULATING SUBSTRATE WHICH IS POSITIONED BETWEEN THE LAYERS OF CIRCUITRY WHICH IS TO BE INTERCONNECTED. UPON HEATING, THE SOLDER MELTS TO PERMIT THE SPRING TO EXPAND AND THEREBY ESTABLISH CONTACT BETWEEN THE CONDUCTED SURFACES. WHEN THE SOLDER AGAIN COOLS, A POSITIVE AND EXTREMELY RELIABLE CONNECTION IS ESTABLISHED.

Searching for the Multiplier in One-Constraint Optimization Problems

Abstract: One-constraint optimization problems are approached via Lagrange multipliers. Sequential search schemes for generating suitable trial multiplier values are compared, and it is shown that, in general, the minimax sequential search is bisection. For certain applications, it pays to design search procedures that take advantage of special structure, such as recursively defined functions. An efficient, one-pass search procedure based on bisection for a multi-item, multi-echelon inventory problem is also presented.

Card module and end wall treatment facilitating heat transfer and sliding

Abstract: An electrical packaging arrangement is described wherein individual electrical components are mounted on printed wiring boards with the body of the components in physical contact with heat sink strip members also located on the printed wiring boards. These heat sink strip members terminate at the edge of the board and the board is adapted to be inserted into slots provided in a frame member such that the frame member acts as a heat sink. The invention resides in providing a coating of a material having properties of high thermal conductivity and a low coefficient of friction between the heat sink strips on the edge of the board and the frame member. In practice, it is found that a coating of Teflon between the edge of the boards and the frame member provides excellent results.

Direction finder system

Abstract: A high frequency radio direction finder receiver system of the over-lapping lobe switching type utilizes an array of lineal antenna elements formed of crossed multiple-element receiver antenna systems sharing one directly coupled receiver antenna element in common. Lobe switching is afforded through bias voltage control of a characteristic of the elements by semiconductor switching circuits.

Keyboard apparatus with moisture proof membrane

Abstract: An electromechanical keyboard for use with a typewriter or other computer type data entry device designed to meet stringent environmental specifications. The electrical switches employed on the keyboard are totally enclosed in a metal compartment and are actuated through a deformable membrane such that moisture and dust cannot deleteriously affect the switches. Because the switches are contained within a metal compartment, a high degree of RFI shielding is afforded so that radiated emanations are low.

Numerical models of a tropical cumulus cloud with bilateral and axial symmetry1

Abstract: Two versions of a numerical model for cumulus convection are compared. One is symmetrical about a vertical plane, the other about a vertical axis. It is found that the axisymmetric model grows more vigorously than the other and more realistically represents the relations between updraft and downdraft, the shape, and other characteristics. The previous findings of Ogura are generally confirmed and extended.

Visual pulmonary meter

Abstract: A pocket-sized pulmonary meter which includes a hollow cylindrical chamber for slidably receiving a piston. A breathing tube assembly communicating with one end of the cylindrical chamber forms a flow passageway terminating with a mouthpiece through which a patient can exhale into the cylindrical chamber and correspondingly move the piston by this expiratory force. An air exit regulator is provided at the other end of the cylindrical chamber and has calibrated registering apertures to selectively vary the rate at which air can escape from the chamber and will thus control resistance to piston movement. The breathing tube may further include an adapter for introducing an inhalator. In an alternate embodiment the device is provided with a slidable gate valve and adapter for securing a medicament dispenser whereby rotation of the mouthpiece will selectively operate the valve and will permit either inhalation of the medicine or exhalation into the cylindrical chamber.

Counter emf commutated self-starting brushless d.c. motor

Abstract: The stator windings of a brushless DC motor are energized through individual silicon controlled rectifiers arranged in a ring counter circuit which is triggered from a pulse source. When the motor is to be started, an AND gate forces the first pulse to trigger a specific silicon controlled rectifier. The AND gate then permits subsequent pulses to be steered to various silicon controlled rectifiers in the desired sequence. The pulse source is synchronized through an OR gate coupled to receive signals from each stator winding. When a given silicon controlled rectifier is turned off, the corresponding stator winding is deenergized. The motion of the rotor, however, induces a counter EMF in the deenergized winding. This counter EMF is applied through the OR gate to synchronize the pulse source.

Collision avoidance display apparatus for maneuverable craft

Abstract: Collision avoidance display apparatus that provides indicia representative of present positions of intruding vehicles as well as predicted tracks thereof. Each track terminates in a region representative of the area to be avoided to assure passing the corresponding intruding vehicle by at least a predetermined distance. These displayed indicia provide information for assessing maneuvers to avoid collision with the intruding craft.

Automatic terminal bridge control system

Abstract: Apparatus for aligning one or more motorized terminal bridges to one or more doors in a vehicle enabling the loading and unloading of passengers and freight. The apparatus includes control circuits responsive to signals from a remotely located control panel which provides drive signals used in the initial positioning of each bridge. An electro-optical device in each bridge is locked onto a reflective type material affixed to the vehicle in the vicinity of each door. Transducers mounted in various sections of the bridges determine the spatial position of the bridges with respect to the terminal after initial positioning. The transducers cooperate with the electrooptical device to produce drive signals that steer and control the speed of each bridge until pressure contacts on each bridge indicate precise alignment with each door.

Digital waveform generator

Abstract: A digital waveform generator for providing digital waveforms particularly of the sinusoidal type. The invention comprises means for providing a sequence of digital numbers whose values vary in accordance with the phase versus time function of the sinusoidal waveform to be generated. The function of time may be linear or nonlinear in accordance with the desired waveform. The sequence of numbers is utilized to address a digital memory wherein is stored the digital sinusoidal functional values corresponding to the digital phase values. As the sequence of phase numbers addresses the memory in accordance with the function of time, the corresponding sequence of sinusoidal numbers are provided by the memory, thus generating the desired digital waveform. Two embodiments are disclosed, one of which utilizes two registers for controlling the frequency and phase, respectively, of the output waveform. The other embodiment utilizes a difference equation computer to approximate the phase function by a recursively generated polynomial function of time.

Solutions for a stochastic model of neuronal spike production

Abstract: Equations for a random-walk model describing the production of nerve impulses have been derived for the general case in which noisy depolarizations of the membrane potential are subject to a force that tends to restore the potential to an equilibrium, or “resting,” value. This model, corresponding to the Ornstein-Uhlenbeck process, was developed previously to account for observed patterns of firing in neurons in which the membrane potential starting from a fixed value undergoes a one-dimensional random walk and triggers an impulse when its value reaches the critical “threshold value.” Identifying neuron firing intervals with the first-passage time distribution for the associated random walk allows us to predict the interval statistics for a neuron from parameters associated with input to the neuron and certain parameters intinsic to the neuron itselt. The equations for the random-walk model have been solved by several techniques, permitting, for the first time, direct comparison between the output of the model and empirically observed interval distributions.

Measurements of the stability of bleached photographic phase holograms.

Abstract: Although efficient high quality, bleached holograms have been made using photographic film, the tendency of the bleach products to darken upon exposure to light seriously limits their usefulness in many practical situations. Nevertheless, the great sensitivity of photographic emulsions makes their use in holography highly desirable. To shed light on the problem of stability, relative measurements of light induced darkening were made on heavily exposed plates bleached to yield one of the reaction products: silver chloride, silver bromide, silver iodide, and silver ferricyanide. We have found that the resistance of the emulsion to darkening increases significantly as the molecular weight of the halide ion is increased. Efficient, high quality, silver iodide holographic gratings usable over the wavelength range from 450 nm to 1200 nm, have been made which exhibit complete immunity to darkening when exposed to white light. Representative measurements of holograms made on Agfa 8E70 plates using the more stable emulsions are presented.

Prolegomena to policy sciences

Abstract: Establishment of policy sciences as a new supradiscipline involves a scientific revolution, requiring fargoing innovations in basic paradigms. Particularly essential are: (1) Integration between various disciplines, and especially of social sciences with analytical decision approaches; (2) bridging of the “pure” vs. “applied” dichotomy; (3) acceptance of tacit knowledge as a scientific resource; (4) changes in interface between science and values; (5) broad time perspectives; (6) focus on metapolicies; (7) commitment to policymaking improvement; and (8) concern with extrarational and irrational processes, such as creativity. Unique subjects of policy sciences, opened up by these paradigms, include, among others: (a) Policy analysis, which involves critical changes in systems analysis so as to permit application to complex policy issues; (b) policy strategies, involving determination of postures and main guidelines for specific policies, such as on degrees of incrementalism vs. innovation and on attitudes to risks; and (c) policymaking system redesign, including evaluation and improvement of the policymaking system, e.g., through changes in one-person-centered high-level decisionmaking, development of politicians, and institutionalization of social experimentation. Development of policy sciences requires many innovations in research, teaching, and professional activities. It constitutes a main effort to reconstruct the role of intellectualism and rationality in human affairs and, therefore, justifies intense efforts.

New variational principle in electromagnetics

Abstract: A new variational principle that applies to a wide class of electromagnetic problems is presented. This principle has the distinctive characteristic of always producing linear algebraic equations when the Rayleigh-Ritz procedure is applied using a trial field composed of a linear combination of variational parameters. The new technique is applied to a general class of antenna problems, and is specialized to the case of a dielectrically coated slot antenna. Experimentally observed admittance values at X band are presented and compared with theoretical predictions.

Apparatus for measuring frequency modulation noise signals and for calibrating same

Abstract: Apparatus is provided for the measurement of frequency modulation noise on the carrier signal output of a low-noise, low-power, high-frequency diode oscillator under test. An auxiliary injection phase-locked oscillator, driven by the oscillator under test, is used to provide a signal of sufficient level for operation of a high-frequency discriminator used for noise measurement. The auxiliary oscillator may additionally be used for calibration of the discriminator preliminary to taking noise measurements.