Topic

A mathematical model that represents several physical and mental behaviors has been developed to enable the phenomenological description of basic functions of immune systems. This development is part of a continuing effort to improve the autonomy of robots and spacecraft by use of computational methods...

A mathematical model of a quantum analog-computing device that would simulate the human decision-making process has been developed. Like the immune-inspired- computing model described in the preceding article, this model is intended to contribute to improvement in the autonomy of robots and spacecraft.

A little-known parametric form of an infinite impulse response (IIR) filter has been found to be useful in digital postprocessing of noisy test signals. The filter equation is: y(n) = α[x(n) + x(n – 1)] + γy(n – 1),

A report discusses tests of finger seals, which were described in “Pressure- Balanced, Low-Hysteresis Finger Seal” (LEW-16840), which appears on page 52 in this issue. Like a labyrinth or brush seal, a finger seal is used (typically in a gas turbine) to minimize a leakage flow along a rotating shaft. The report describes...

A report discusses three designs of proposed low-power, zero-vibration coolers for infrared instruments planned to be flown aboard spacecraft to perform astrophysical observations far from Earth. The designs take advantage of the radiative precooling available in the projected deep-space operational...

A report presents an experimental study of time-resolved, temperature-dependent photoluminescence in InxGa1–x As/GaAs specimens containing In0.6Ga0.4As quantum dots (QDs) distributed at several different areal densities on a GaAs surface and capped with GaAs. The specimens were fabricated by...

A report presents a theoretical and experimental study of amplification in electronic circuits that include combinations of discrete light sources (e.g., lightemitting diodes) and photodetectors (e.g., reverse-biased photodiodes), which combinations perform essentially the same functions as...

This paper presents a study of area production in mixing layers undergoing transition to turbulence. These layers evolve from the mixing of two initially segregated counterflowing streams under supercritical conditions. The study may contribute to development of means to control area...

A report discusses the development of thin-shell curved mirrors comprised of metallic multilayer nanolaminate substrates that contain integral inplane actuators for controlling surface figure with micron-level precision. These mirrors, intended for incorporation into scientific imaging...

Missions to the surface of Mars pose unique thermal-control challenges to rover and lander systems. With diurnal temperature changes greater than 100 °C, the presence of a Mars atmosphere, and limited power for night-time heating, the thermal-control engineer is faced with a fundamental...

A computational process converts a sequence of digitized video images of the same scene into stabilized, coregistered images of an area of interest within the scene. The process corrects for motion of the area of interest or of the camera (as manifested by rotation, translation, and/or...

A report presents a study of the complexity of an algorithm that performs model-based diagnosis of a complex hardware system. [In model-based diagnosis, an algorithm detects logical inconsistencies between observational data and a description (mathematical model) of the system.] In the study, the problem of...

Twelve reports present concepts for the design of structural and functional systems, subsystems, and components of the proposed TransHab module — an inflatable, lightweight habitation module that would be used by crewmembers of the International Space Station and would serve as a prototype of habitation...

This report describes a study of threedimensional, temporal mixing layers between different fluids initially flowing at different velocities under supercritical conditions. The study involved direct numerical simulations by use of a validated mathematical model of high-pressurefluid...

A proposed infrared CO2 sensor, operated in conjunction with suitable readout, data-processing, and control circuitry, could be calibrated repeatedly during operation to compensate for changes in sensor response induced by such phenomena as aging and changes in temperature. The sensor would...

A solid-state sensor was developed that measures the concentrations of one or more gases of interest in a mixture of gases. This simple solid-state sensor produces a voltage signal that is sensitive to CO concentration from percent to ppm (parts per million) levels. It was intended originally for use in...

A technical report enunciates the concept of a hierarchy of sensor classes (meaning transducers, associated circuitry, and embedded software) that have different levels of intelligence, and discusses issues pertaining to the development of sensors of the highest level of intelligence, called cognitive. The other...

The NASGRO 3.0 computer program is an advanced version of a program used by NASA and the European Space Agency for fracture-control analysis of space-system structures and other hardware. The prior version, NASA/FLAGRO 2.0, was described in “Updated Fatigue-Crack-Growth and...

SEQ_GEN is a component of the Sequence Subsystem computer program, which assists in generating a sequence of commands to be executed by a control computer aboard a spacecraft to perform scientific observations and supporting engineering actions in response to requests by numerous users. SEQ_GEN assists a...

Closed Loop Accounting Management System (CLAMS) is a computer program for Web-based distribution and tracking of memoranda within an organization. An item for distribution is entered by a user who has administrative access. The item is assigned to affected users, to whom e-mail messages are...