Special Coverage

Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines

Chamber for Aerosol Deposition of Bioparticles

Standard coupons can be covered with reproducible areal concentrations of bioparticles.

The laboratory apparatus shown in the figure is a chamber for aerosol deposition of bioparticles on surfaces of test coupons. It is designed for primary use in inoculating both flat and three-dimensional objects with approximately reproducible, uniform dispersions of bacterial spores of the genus Bacillus so that the objects could be used as standards for removal of the spores by quantitative surface sampling and/or cleaning processes. The apparatus is also designed for deposition of particles other than bacterial spores, including fungal spores, viruses, bacteriophages, and standard micron-sized beads. The novelty of the apparatus lies in the combination of a controllable nebulization system with a settling chamber large enough to contain a significant number of test coupons. Several companies market other nebulizer systems, but none are known to include chambers for deposition of bioparticles to mimic the natural fallout of bioparticles.

Posted in: Briefs, TSP, Bio-Medical, Medical, Bacteria, Biomaterials, Test equipment and instrumentation

Hyperspectral Sun Photometer for Atmospheric Characterization and Vicarious Calibrations

Data acquired by such devices are used in atmospheric, pollution, and solar energy studies.

A hyperspectral sun photometer and associated methods have been developed and demonstrated. Sun photometers are used to measure total (global), direct, and diffuse at-surface solar irradiance. The data acquired by sun photometers are used in atmospheric, pollution, and solar energy studies. In addition, the data acquired by sun photometers are used for radiometric vicarious calibration of optical remote-sensing systems. Sun photometer measurements at various wavelengths can be analyzed to estimate molecular scattering, aerosol extinction, and columnar concentrations of water vapor, ozone, and trace gases in the atmosphere.

Posted in: Briefs, Physical Sciences, Measurements, Fiber optics, Fiber optics, Sun and solar, Product development

Shaker Fatigue Testing of a Turbine Engine Compressor Blade

Linear dynamic finite-element analysis was used to optimize testing.

Hamler Test and Analysis (HTA) provides testing, design, and finite-element analysis (FEA) consulting services, specializing in vibration measurement and experimental vibration analysis tools such as tap testing, modal analysis, operating deflection shapes analysis, and rotating machinery analysis. HTA was contracted to perform physical fatigue testing of a compressor blade from a stationary gas turbine engine used for power generation. Electrodynamic shaker testing was required to verify the client’s analytical vibratory high-cycle fatigue life prediction methodology. The first phase of the shaker testing involved vibrating several blades to failure at the first bending mode, and the second phase involved testing several blades to failure at the first torsion mode.

Posted in: Briefs, Physical Sciences, Propellers and rotors, Finite element analysis, Fatigue, Vibration, Vibration, Compressors, Gas turbines

Dynamic Stability and Gravitational Balancing of Multiple Extended Bodies

Feasibility of a non-invasive compensation scheme was analyzed for precise positioning of a massive extended body in free fall using gravitational forces influenced by surrounding source masses in close proximity. The N-body problem of classical mechanics is a paradigm used to gain insight into the physics of the equivalent N-body problem subject to control forces.

Posted in: Briefs, Physical Sciences, Mathematical models, Attitude control, Attitude control, Vehicle dynamics

Simulation of Stochastic Processes by Coupled ODE-PDE

A document discusses the emergence of randomness in solutions of coupled, fully deterministic ODE-PDE (ordinary differential equations-partial differential equations) due to failure of the Lipschitz condition as a new phenomenon. It is possible to exploit the special properties of ordinary differential equations (represented by an arbitrarily chosen, dynamical system) coupled with the corresponding Liouville equations (used to describe the evolution of initial uncertainties in terms of joint probability distribution) in order to simulate stochastic processes with the proscribed probability distributions. The important advantage of the proposed approach is that the simulation does not require a random-number generator.

Posted in: Briefs, TSP, Information Sciences, Computer simulation, Statistical analysis

Cluster Inter-Spacecraft Communications

A document describes a radio communication system being developed for exchanging data and sharing data-processing capabilities among spacecraft flying in formation. The system would establish a high-speed, low- latency, deterministic loop communication path connecting all the spacecraft in a cluster. The system would be a wireless version of a ring bus that complies with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus enhancement to the IEEE standard developed at NASA’s Jet Propulsion Laboratory). Every spacecraft in the cluster would be equipped with a ring-bus radio transceiver. The identity of a spacecraft would be established upon connection into the ring bus, and the spacecraft could be at any location in the ring communication sequence.

Posted in: Briefs, TSP, Electronics & Computers, Architecture, Data exchange, Wireless communication systems, Architecture, Data exchange, Wireless communication systems, Spacecraft

Low-Impact Mating System for Docking Spacecraft

A document describes a low-impact mating system suitable for both docking (mating of two free-flying spacecraft) and berthing (in which a robot arm in one spacecraft positions an object for mating with either spacecraft). The low-impact mating system is fully androgynous: it mates with a copy of itself, i.e., all spacecraft and other objects to be mated are to be equipped with identical copies of the system. This aspect of the design helps to minimize the number of unique parts and to standardize and facilitate mating operations. The system includes a closed-loop feedback control subsystem that actively accommodates misalignments between mating spacecraft, thereby attenuating spacecraft dynamics and mitigating the need for precise advance positioning of the spacecraft.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Adaptive control, Architecture, Connectors and terminals, Adaptive control, Architecture, Connectors and terminals, Spacecraft

Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy

A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes.

Posted in: Briefs, TSP, Physical Sciences, Spectroscopy, Spectroscopy, Composite materials, Resins, Non-destructive tests, Test procedures

Gold-on-Polymer-Based Sensing Films for Detection of Organic and Inorganic Analytes in the Air

A document discusses gold-on-polymer as one of the novel sensor types developed for part of the sensor development task. Standard polymer- carbon composite sensors used in the JPL Electronic Nose (ENose) have been modified by evaporating 15 nm of metallic gold on the surface. These sensors have been shown to respond to alcohols, aromatics, ammonia, sulfur dioxide, and elemental mercury in the parts-per-million and parts-per-billion concentration ranges in humidified air.

Posted in: Briefs, TSP, Physical Sciences, Sensors and actuators, Sensors and actuators, Air pollution, Chemicals, Composite materials, Polymers

Genetic Algorithm Optimizes Q-LAW Control Parameters

A document discusses a multi-objective, genetic algorithm designed to optimize Lyapunov feedback control law (Q-law) parameters in order to efficiently find Pareto- optimal solutions for low-thrust trajectories for electronic propulsion systems. These would be propellant-optimal solutions for a given flight time, or flight time optimal solutions for a given propellant requirement. The approximate solutions are used as good initial solutions for high-fidelity optimization tools. When the good initial solutions are used, the high-fidelity optimization tools quickly converge to a locally optimal solution near the initial solution.

Posted in: Briefs, TSP, Information Sciences, Trajectory control, Mathematical models, Optimization, Propellants, Spacecraft fuel

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