Engineering topics
Publications and source records attributed to Gat, N..
Each material has unique spectral distribution that can be viewed as its fingerprint. Advanced hyper and ultra spectral sensors will produce large amount of data. Therefore, advanced capabilities are required that can effectively deal with large data cubes, possibly in real time.
This paper reviews the activities at OKSI related to imaging spectroscopy presenting current and future applications of the technology. The authors discuss the development of several systems including hardware, signal processing, data classification algorithms and benchmarking techniques to determine algorithm performance. Signal processing for each application is tailored by incorporating the phenomenology appropriate to the process, into the algorithms. Pixel signatures are classified using techniques such as principal component analyses, generalized eigenvalue analysis and novel very fast neural network methods. The major hyperspectral imaging systems developed at OKSI include the Intelligent Missile Seeker (IMS) demonstration project for real-time target/decoy discrimination, and the Thermal InfraRed Imaging Spectrometer (TIRIS) for detection and tracking of toxic plumes and gases. In addition, systems for applications in medical photodiagnosis, manufacturing technology, and for crop monitoring are also under development.
The GGSF is specifically designed to accommodate micro-g experiments that investigate long-term effects and interactions between submicron to centimeter size particles. The paper introduces the science disciplines and the type of experiments that are currently envisioned for the GGSF. The broad range of science and technology requirements are discussed, and the Space Station Freedom (SSF) accommodations, and available utilities are reviewed. Based on the requirements and the available accommodations, a facility conceptual design is outlined. The required subsystems are listed, and the rationale and considerations that lead to the selected approach, delineated. The present GGSF concept is that of a modular facility system comprising a flight rack and an array of fully compatible and interchangeable subsystems that are designed to meet a diverse set of science requirements. The modularity allows for future upgrade of various subsystems as technology evolves and for introduction of new modules to accommodate new or different experiments. These features are essential for a facility that is expected to be in service on board the SSF for 10 years or more.
Theoretical estimates and experimental measurements of the effects of sparks on ordered droplet motion are reported for 1-mm-diameter water and hydrocarbon droplets positioned 0.5 mm from the axis of electrodes are reported. The discussion focuses primarily on two-electrode, surge-type spark breakdowns with quasi-steady electric fields applied. Multiple electrode pairs and alternating electric fields and their effects on ordered droplet motion are also briefly discussed.
The mid-deck lockers of the STS and the requirements for operating an experiment in this region are described. The design of the surface tension induced convection and the free surface phenomenon experiments use a two locker volume with an experiment unique structure as a housing. A manual mode is developed for the Surface Tension Induced Convection experiment. The fluid is maintained in an accumulator pre-flight. To begin the experiment, a pressurized gas drives the fluid into the experiment container. The fluid is an inert silicone oil and the container material is selected to be comparable. A wound wire heater, located axisymmetrically above the fluid can deliver three wattages to a spot on the fluid surface. These wattages vary from 1-15 watts. Fluid flow is observed through the motion of particles in the fluid. A 5 mw He/Ne laser illuminates the container. Scattered light is recorded by a 35mm camera. The free surface phenomena experiment consists of a trapezoidal cell which is filled from the bottom. The fluid is photographed at high speed using a 35mm camera which incorporated the entire cell length in the field of view. The assembly can incorporate four cells in one flight. For each experiment, an electronics block diagram is provided. A control panel concept is given for the surface induced convection. Both experiments are within the mid-deck locker weight and c-g limits.