Tech Briefs

Development of Free Molecule Flow Equations from a Transient, Asymmetric Source

Molecular flow model is explored as a tool to describe an unusual variety of plume interaction issues. Goddard Space Flight Center, Greenbelt, Maryland The analysis and simulation of gases expanding from sources such as rocket nozzles into vacuum, or the effects plumes from these sources create when they interact with solid surfaces, present a considerable challenge to the scientific and engineering communities. As a plume expands into vacuum, density levels, and hence collision rates, decrease rapidly by many orders of magnitude. The main difficulty lies in accurately describing a flow field extending from continuum flow at the nozzle exit, through the transition regime, and reaching free molecule behavior within a relatively short distance downstream. For thrusters, flow at the nozzle exit is usually characterized by high exit velocities and relatively high Mach numbers. Even in regions where significant intermolecular collision rates occur, relative velocity levels are low, and little thermal scattering occurs normal to the mainly radial streamlines. Such observations lead one to consider describing the expansion under certain circumstances using free molecule theory.

Posted in: Briefs, TSP, Electronics & Computers

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Formal Validation of Model-Based Fault Management Design Solutions

A number of advantages of modeling fault protection logical design, executing the model, and running a model checker are identified. NASA’s Jet Propulsion Laboratory, Pasadena, California Model-Based System Engineering is becoming widely adopted at JPL and in industry because model-centric systems introduce improved methods of system engineering. As systems with ever-increasing complexity are developed at JPL, model-centric engineering be comes essential for design, test, and validation. Validation of FP designs is historically problematic, with many examples of inadequate resources (people, time, and budget) and/or unexpected problems. Many factors contribute to these issues, but the problem can be traced to a lack of appreciation of system complexity. When considering a system, there are significantly more ways the system can fail (contingency paths) than ways it can succeed (nominal paths). As NASA continues to develop more complex and capable spacecraft, the behavior state space will increase, stressing the ability of teams to properly understand system behavior.

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Fast Block Transforms on Large Binary Datasets in the Cloud Using Hadoop Streaming

NASA’s Jet Propulsion Laboratory, Pasadena, California A software framework on top of Hadoop Streaming enables both the processing of binary data in the cloud, and the freedom for the developer to implement his or her mapper and reducer programs in any language, rather than re-implementing existing solutions in Java, or repackaging existing binary data into a text format. Binary data is partitioned into chunks that are kept in a persistent data storage medium. A textual list of filenames for these chunks is piped into a Hadoop Streaming mapper program, which then reads the corresponding files, computes block transforms locally, and writes the results back to persistent data storage. The mapper program is stored on all compute nodes, and the filenames are distributed in parallel across the cluster, so that the workload is evenly distributed and the end-to-end block transform speedup is roughly given by the number of nodes in the cluster.

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Design and Engineering of Process Plants Based on the “Lego Principle”

Users can add automation modules or switch them off in line with requirements. Festo Corporation, Hauppauge, New York Manufacturers in the process industries need to adjust to smaller batches and different types of product in the same plant. Plants based on the “Lego principle” are designed and engineered precisely to the respective task, whether for the production of a specific product in units per time unit, or for the throughput of a specific substance in a quantity per time unit. The mechanical design of the plant as a whole is geared towards meeting specifications and guaranteeing the required performance data over the projected lifecycle of the plant. The corresponding automation is carried out using management systems comprising process-specific (control) components, operating and monitoring stations, as well as engineering stations. The entire process is centrally controlled by a single management system.

Posted in: Briefs, Industrial Controls & Automation

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Electrochemically Enhanced Mechanical Polishing of Optics

A combined method results in a significant reduction of manufacturing time for optical components. Marshall Space Flight Center, Alabama Optical component fabrication using metals or ceramic materials involves many grinding and/or machining and polishing steps to achieve the proper form to the tolerances of imaging or photonic focusing instruments. These instruments range from infrared sensors, through visible and ultraviolet, to X-ray and even thermal neutron focusing. Conventional manufacturing methods require many days or even months of precise polishing to improve selected areas of the component.

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Expendable Cooling System for Venus Lander Concept

The concept could be applicable to the trucking industry to provide temporary cooling where power is not readily available. NASA’s Jet Propulsion Laboratory, Pasadena, California This innovation is a concept for a novel thermal architecture that would enable a day-long surface mission on Venus. A Venus lander mission could last much longer than a few hours on the surface of the planet by absorbing heat from the Venus environment, and from the electronics within the lander, by using an expendable fluid cooling system. The fluid would evaporate in the structural shell, absorbing heat coming from the ambient environment, keeping the shell relatively cool compared to the ambient temperature. The evaporating fluid would create a liquid flow from a reservoir used to cool electronic components within the lander. The liquid reservoir must be contained within the lander structure to serve as a heat sink to maximize the lander lifetime on the surface. A pressure tank would be used to bring the fluid to a point where it could boil and vent into the Venus atmosphere.

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Rapid Quench Furnace for Processing Powder in an Inert Environment

The system is able to process particles and/or powder, preserving inert environmental conditions throughout. Langley Research Center, Hampton, Virginia Ongoing work in the development and characterization of sensory materials requires the development of shape memory alloy (SMA) powder or particles. These are embedded in structural material so that the progression of localized damage that occurs during fatigue crack growth will produce an audible acoustic emission (AE) as the SMA transforms from an austenite phase to a martensite phase. In order to set the shape memory effect in these particles, the SMA must be solution-treated (ST) to produce the austenite phase, and rapidly quenched to or below room temperature to preserve the austenite phase at room temperature.

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