materials and coatings
Carbonated Cement for Production of Concrete with Improved Properties
The NASA cement innovation describes a method to make solid carbon material from CO<sub>2</sub> captured during the cement-making process, and for using that carbon material in the mixture to improve cement properties. Doing so provides a direct use for the captured CO<sub>2</sub>, eliminating any CO<sub>2</sub> storage/disposal issues and providing an improved cement product. The innovation employs a chemical reaction, known as the Bosch process, which uses hydrogen gas and catalysis to reduce the CO<sub>2</sub> to solid carbon and water. Cement manufacturing is uniquely suited to the use of the Bosch process. Cement manufacturing requires high temperatures, and harnessing this excess heat limits the total energy required to maintain a Bosch process at a cement plant. Also, cement contains iron, a metal shown to be an exceptional catalyst for the Bosch process. Thus, the cement product itself can be used as the catalyst for the reaction, also serving as a carbon sink. This eliminates any requirements for the storage or disposal of the waste carbon captured from CO<sub>2</sub> emissions. Test evaluations at the bench scale have provided encouraging indications of enhanced mechanical properties for the carbon-containing cement materials. In particular, the findings suggest that the carbon in the concrete might delay the environmental breakdown of concrete due to the blocking effect of the carbon on harmful ions (e.g., chlorine).
information technology and software
Estimating a Remaining Useful Life in Batteries
This technology provides a method having a training (off-line) mode and a subsequent run-time (on-line) mode for estimating a remaining useful life (RUL) of an object that is in active use for at least part of the time (an active object). In the training mode, the system collects training data, including operating conditions of the object, measurements from sensors monitoring the system, and the ground truth indicating the true extent of damage. The system extracts or identifies precursors of failure from the sensor data by analyzing their correlation to the ground truth. The feature domain size is optionally reduced by eliminating one or more features that are highly correlated to other features, such that their exclusion does not diminish information about damage progression in the system. The invention decomposes the prognostic problem into two separate regression problems: the feature-to-damage mapping and the operational conditions-to-damage rate mapping. The regressions can be carried out using methods that employ either physics-based models, data-driven techniques, or a hybrid combination thereof. Regression algorithms like Gaussian Process Regression (GPR), Relevance Vector Machine (RVM), etc., can be used to solve each of these mapping subtasks. The decomposition allows the technique to explicitly account for accumulated damage up to now and anticipated future damage progression.
information technology and software
Inductive Monitoring System
The Inductive Monitoring System (IMS) software provides a method of building an efficient system health monitoring software module by examining data covering the range of nominal system behavior in advance and using parameters derived from that data for the monitoring task. This software module also has the capability to adapt to the specific system being monitored by augmenting its monitoring database with initially suspect system parameter sets encountered during monitoring operations, which are later verified as nominal. While the system is offline, IMS learns nominal system behavior from archived system data sets collected from the monitored system or from accurate simulations of the system. This training phase automatically builds a model of nominal operations, and stores it in a knowledge base. The basic data structure of the IMS software algorithm is a vector of parameter values. Each vector is an ordered list of parameters collected from the monitored system by a data acquisition process. IMS then processes select data sets by formatting the data into a predefined vector format and building a knowledge base containing clusters of related value ranges for the vector parameters. In real time, IMS then monitors and displays information on the degree of deviation from nominal performance. The values collected from the monitored system for a given vector are compared to the clusters in the knowledge base. If all the values fall into or near the parameter ranges defined by one of these clusters, it is assumed to be nominal data since it matches previously observed nominal behavior. The IMS knowledge base can also be used for offline analysis of archived data.
mechanical and fluid systems
Compact Vibration Damper
Structural vibrations frequently need to be damped to prevent damage to a structure. To accomplish this, a standard linear damper or elastomeric-suspended masses are used. The problem associated with a linear damper is the space required for its construction. For example, if the damper's piston is capable of three inches of movement in either direction, the connecting shaft and cylinder each need to be six inches long. Assuming infinitesimally thin walls, connections, and piston head, the linear damper is at least 12 inches long to achieve +/-3 inches of movement. Typical components require 18+ inches of linear space. Further, tuning this type of damper typically involves fluid changes, which can be tedious and messy. Masses suspended by elastomeric connections enable even less range of motion than linear dampers. The NASA invention is for a compact and easily tunable structural vibration damper. The damper includes a rigid base with a slider mass for linear movement. Springs coupled to the mass compress in response to the linear movement along either of two opposing directions. A rack-and-pinion gear coupled to the mass converts the linear movement to a corresponding rotational movement. A rotary damper coupled to the converter damps the rotational movement. To achieve +/- 3 inches of movement, this design requires slightly more than six inches of space.
materials and coatings
Polyamides are polymers that are similar to polyimides (another polymer that has been developed for use in aerogels). However, because the amide link is a single chain while the imide link is a ring structure, polyamide aerogels can be made less stiff than polyimides, even though a similar fabrication process is used. The precursor materials can be made from any combination of diamine and diacid chloride. Furthermore, NASA Glenn researchers have found methods for using combinations of diamines and disecondary amines to produce polyamide aerogels with tunable glass transition temperatures, for greater control of features such as flexibility or water-resistance. In the first step of the fabrication process, an oligomeric solution is produced that is stable and can be prepared and stored indefinitely as stock solutions prior to cross-linking. This unique feature allows for the preparation and transport of tailor-made polyamide solutions, which can later be turned into gels via the addition of a small amount of cross-linker. When the cross-linking agent is added, the solution can be cast in a variety of forms such as thin films and monoliths. To remove the solvent, one or more solvent exchanges can be performed, and then the gel is subjected to supercritical drying to form a polyamide aerogel. NASA Glenn's polyamide aerogels can be fully integrated with the fabrication techniques and products of polyimide aerogel fabrication, so hybrid materials which have the properties of both classes are easily prepared. As the first aerogels to be composed of cross-linked polyamides, these materials combine flexibility and transparency in a way that sets them apart from all other polymeric aerogels.
Strobing to Mitigate Vibration for Display Legibility
The dominant frequency of the vibration that requires mitigation can be known in advance, measured in real time, or predicted with simulation algorithms. That frequency (or a lower frequency multiplier) is then used to drive the strobing rate of the illumination source. For example, if the vibration frequency is 20 Hz, one could employ a strobe rate of 1, 2, 4, 5, 10, or 20 Hz, depending on which rate the operator finds the least intrusive. The strobed illumination source can be internal or external to the display. Perceptual psychologists have long understood that strobed illumination can freeze moving objects in the visual field. This effect can be used for artistic effect or for technical applications. The present innovation is instead applicable for environments in which the human observer rather than just the viewed object undergoes vibration. Such environments include space, air, land, and sea vehicles, or on foot (e.g., walking or running on the ground or treadmills). The technology itself can be integrated into handheld and fixed display panels, head-mounted displays, and cabin illumination for viewing printed materials.
materials and coatings
Fiber-Metal Laminate Manufacturing Technique
Fiber-Metal Laminates (FMLs) are composite materials that consist of conventional fiber reinforced plastics with the addition of a metal component, typically a foil or mesh layer(s). The metal component offers the advantage of incorporating metal-like properties to the composite construction. While a range of potential advantages and applications have been discussed for FMLs, the primary application to date has been for aircraft structures, with one potential advantage being the lightning strike protection (LSP) offered by the improved electrical conductivity. As aircraft construction has moved to composite structures, there has been an increasing need for such conductive composites. Similarly, with increasing use of composites for other large structures, e.g. wind turbines, there are an increasing number of potential applications for lightning strike protection materials. Other advantages of FML are improved impact and fire resistance. This innovation provides a method for making FML materials that incorporate nanotube reinforcement. The method involves the use of RF plasma spray to directly form and deposit nanotube materials onto fibers/fabrics, which can then be manufactured into composite structures by infiltrating the fiber with resin, and consolidating the structure via autoclave processing or via the use Vacuum Assisted Resin Transfer Molding (VARTM) composite manufacturing methods. Nanotubes incorporated into the structure in this manner can be of several types, for example boron nitride or carbon nanotubes. The objective of this innovation is to incorporate the nanotube materials in the FML in order to improve the mechanical properties.
materials and coatings
Sensory Metallic Materials
While almost all advancements in nondestructive evaluation (NDE) focus on improving the NDE equipment and techniques, any testing is inherently limited by the response of the materials being tested. This technology seeks to improve the response of the material itself by embedding shape memory alloy (SMA) particles in the metallic structural alloy in a manner that does not compromise the structural integrity of the material. These SMA particles undergo a martensitic phase change (crystallographic change) in response to strain (e.g., a crack tip causing local deformation). The phase change produces an acoustic emission and a change in magnetic properties that can easily be detected and monitored, providing a means for enhanced NDE. The advantage is either that (1) the technology makes available existing NDE techniques that were not applicable before because of the type of structural material being used (the particles add new physics to the base structure) or (2) the technology enhances NDE because the SMA particles create conditions that are easier to detect damage relative to the equivalent level of damage in a structure without particles.
Piezoelectric Fiber Composite Actuator Portfolio
The NASA Langley Composite Actuator portfolio utilizes a NASA-patented (US 6,629,341) and commercialized MFC piezoelectric fiber composite actuator platform. This actuator platform enables compact, lightweight electroactive actuators, which can be broadly applied to a variety of actuator applications. NASA Langley has developed novel patent-pending actuator designs using the MFC actuator platform and other piezoelectric fiber composites to advance the performance of tunable fiber-optic lasers for distributed FBG sensing. The use of distributed fiber-optic-based sensors has enabled robust, low-cost, intrinsically safe measurement of physical parameters like stress, temperature, pressure, and the presence of certain chemicals. However, widely tunable, mode-hop-free, narrowband laser sources are required to interrogate current NASA-built distributed FBG sensing systems, and traditional diode- and fiber-based lasers cannot meet these requirements. To address these tunable laser shortcomings, NASA Langley has developed a portfolio of actuator architectures CASF, IDEAS, and CMFC. When an optical fiber containing FBGs is strained by the NASA Langley MFC actuators, it shifts the reflected wavelength of the FBG and can be used to tune an optical fiber laser to a specific, mode-hop-free, narrowband output. In addition to providing a wide (4 nm and larger) tuning range, the NASA actuators can also tune the fiber laser at high frequencies (up to 100 Hz), which enables the high-speed interrogation required for NASA distributed sensing systems. The CMFC is also envisioned for applications requiring larger (>25 nm) displacements, yet can be provided in a smaller, lighter form factor than microstages.
mechanical and fluid systems
Lightweight, High-Strength Hybrid Gear
The use of composites in a rotorcraft drive system, with their low density and high strength, can improve power to weight ratio. NASA Glenn inventors have succeeded in reducing the weight of large-scale gears for rotorcraft and other applications, which are conventionally machined from forgings, by using composite material as the web of the gear between the gear teeth and a metallic hub. The hybrid gear has a metallic shaft and outer gear rim, with composite layup between the shaft interface and the gear tooth rim. The Hybrid Gear was built and tested at NASA Glenn and found to be 20% lighter than all-steel gears. In an endurance test consisting of over 300x10<sup>6</sup> gear revolutions at 10,000 RPM and 250 PSI torque load, the hybrid gear operated without problem and showed no fatigue in post-test inspection. Through the use of various composite materials and ply layups, this hybrid gear fabrication method can accommodate complex shapes. Hybrid gear designs can also be tailored to optimize mechanical and acoustic performance, while reducing noise and critical vibration modes.