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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Report on plasma jet printer for sensor fabrication with process parameters optimized by simulation input

The In-Pile Instrumentation program conducts research to develop instrumentation that provides information regarding test conditions, as well as fuel and materials properties during irradiation. Such instruments must be miniaturized, robust to the nuclear reactor environment, and provide real-time data aligned with user needs. Towards this end, additive manufacturing techniques such as aerosol jet printing and Plasma Jet Printing, have demonstrated significant potential for the development of advanced in-pile instrumentation. Process control during the manufacturing process is critical in order to consistently create reliable sensors. This report details experimental and computational work aimed towards improved process control for robust sensor production using printing techniques.

36 MATERIALS SCIENCE↗
NASA NTRS1971

Research, Development and Fabrication of Lithium Solar Cells

This report continues studies on cells made with low temperature (<400degC) single-cycle, lithium diffusion schedules. Measurements of concentration of lithium at the back surface showed that C(sub S) changes with time consisting of a build-up to a maximum value (above 10(exp 17) cm(exp -3)) with gradual decrease at longer diffusion times. Using the estimated C(sub S) values, theoretical lithium profiles were calculated. The calculated concentration near the PN junction was higher than those measured by the capacitance voltage (C-V) technique. The calculated concentration gradients were one-seventh of those measured by C-V methods. Both the concentration and its gradient were proportional to C(sub S). Estimates of C(sub S) obtained by extrapolating from C-V measured values of concentration and gradient near the PN junction, showed a decrease in C(sub S) for longer diffusion times. This fact supported the trend observed in Shipment C-13, where,, at longer times, the spread in values of V(sub oc), lithium concentration, and gradient became greater. The general conclusion was that the I-V characteristics were well controlled, with good cell output, but for longer diffusion times the lithium concentration gradient could have wider spread. The work described has led to greater insight into the lithium distribution dependence on the surface conditions. The surface conditions could be changed by varying the method used to apply lithium. Vacuum evaporation of lithium shows promise, and another exhaustive test of this method is in progress. Shipment C-13 is summarized, and the succeeding lots (C-14, C-15) are described. It is felt that improved monitoring of cell properties is at hand, and that the control of cell fabrication processes has advanced to where the effects of subtle differences in lithium distribution can now be seen. Evaluation is continuing on the best method to scale up the fabrication steps. A different sequence of fabrication is planned for Shipments C-14 and C-15.

Iles, Peter A.↗
NASA NTRS1995

Powder-Coated Towpreg: Avenues to Near Net Shape Fabrication of High Performance Composites

Near net shape parts were fabricated from powder-coated preforms. Key issues including powder loss during weaving and tow/tow friction during braiding were addressed, respectively, by fusing the powder to the fiber prior to weaving and applying a water-based gel to the towpreg prior to braiding. A 4:1 debulking of a complex 3-D woven powder-coated preform was achieved in a single step utilizing expansion rubber molding. Also, a process was developed for using powder-coated towpreg to fabricate consolidated ribbon having good dimensional integrity and low voids. Such ribbon will be required for in situ fabrication of structural components via heated head advanced tow placement. To implement process control and ensure high quality ribbon, the ribbonizer heat transfer and pulling force were modeled from fundamental principles. Most of the new ribbons were fabricated from dry polyarylene ether and polymide powders.

Johnston, N. J.↗
NASA NTRS2003

Wavelet-Based Real-Time Diagnosis of Complex Systems

A new method of robust, autonomous real-time diagnosis of a time-varying complex system (e.g., a spacecraft, an advanced aircraft, or a process-control system) is presented here. It is based upon the characterization and comparison of (1) the execution of software, as reported by discrete data, and (2) data from sensors that monitor the physical state of the system, such as performance sensors or similar quantitative time-varying measurements. By taking account of the relationship between execution of, and the responses to, software commands, this method satisfies a key requirement for robust autonomous diagnosis, namely, ensuring that control is maintained and followed. Such monitoring of control software requires that estimates of the state of the system, as represented within the control software itself, are representative of the physical behavior of the system. In this method, data from sensors and discrete command data are analyzed simultaneously and compared to determine their correlation. If the sensed physical state of the system differs from the software estimate (see figure) or if the system fails to perform a transition as commanded by software, or such a transition occurs without the associated command, the system has experienced a control fault. This method provides a means of detecting such divergent behavior and automatically generating an appropriate warning.

Gulati, Sandeep↗
NASA NTRS2012

Terahertz Radiometer for Outer Planet and Moon Atmospheres (TROPA)

We are developing a prototype instrument platform to demonstrate the feasibility of a wideband spectrometer for planetary applications under a three-year NASA research program. This development focuses on three specific areas needing advancement. First, the terahertz portion consists of an optical bench with dual heterodyne Schottky-mixer based receivers, one for each band. The beams entering the horns of the two receivers are de-multiplexed from the input beam by a polarizing beam splitter. The blocks containing the 560 and 1200 GHz mixer are more highly integrated than previous space instruments to reduce mass and volume. The receivers take a fundamental pump frequency near 30 GHz and multiply up to the submillimeter range. Second, a rapid-tuning, low-phase noise, and low-power 33 GHz range LO synthesizer is being prototyped. The low phase noise requirement is needed because of the factor of 36 multiplication to reach 1200 GHz, giving a requirement that the integrated phase noise from 100 kHz up be less than 0.6 degrees. The synthesizer will require about 6 watts. Finally, we are developing an advanced polyphase filter back-end spectrum analyzer with a bandwidth of 750 MHz, and power consumption of about 3 Watts and 4096 channels. This system is based on a simple three-chip architecture, having a commercial 1.5 GS/s analog-to-digital converter, an ASIC to do the filtering and an advanced FPGA for data processing and control.

spectrometer↗
DOE OSTI2025

Transforming Aeration Energy in Water Resource Recovery Facilities (WRRFs) through Suboxic Nitrogen Removal (Final Report)

The objective of this project was to advance two key technological components—aeration control strategies and process design methodologies—to support the development and broader adoption of suboxic biological nitrogen removal (SBNR). The project focused on achieving the following three goals: • Enhance Model Predictive Control (MPC) Technology: Advance the DO/Nmaster MPC platform from its initial 2018 pilot deployment at the Chico Water Resource Recovery Facility in California to full-scale integration. This included partnering with a blower technology commercialization partner and incorporating machine learning (ML) capabilities to enable nationwide deployment. • Bridge Knowledge Gaps in SBNR Process Design: Address fundamental gaps in SBNR process understanding through controlled pilot-scale testing at a dedicated pilot facility. These efforts supported the development of robust kinetic models to inform reliable SBNR control, operational strategies, and design frameworks. • Demonstrate Full-Scale Implementation of Low DO/SBNR with ML: Transition low dissolved oxygen (DO)/SBNR coupled with ML from pilot-scale trials to full-scale demonstration in flow-through biological nutrient removal (BNR) systems, with the goal of enabling scalable, nationwide adoption in activated sludge treatment processes. The project included demonstration of SBNR at the pilot scale as performed by Hampton Roads Sanitation District (HRSD) and at the full-scale as performed by the Los Angeles County Sanitation Districts' (LACSD) Pomona Water Reclamation Plant (POWRP).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Controlling the helicity of light by electrical magnetization switching

Controlling the intensity of emitted light and charge current is the basis of transferring and processing information. By contrast, robust information storage and magnetic random-access memories are implemented using the spin of the carrier and the associated magnetization in ferromagnets. In this study, the missing link between the respective disciplines of photonics, electronics and spintronics is to modulate the circular polarization of the emitted light, rather than its intensity, by electrically controlled magnetization. Here we demonstrate that this missing link is established at room temperature and zero applied magnetic field in light-emitting diodes through the transfer of angular momentum between photons, electrons and ferromagnets. With spin-orbit torque a charge current generates also a spin current to electrically switch the magnetization. This switching determines the spin orientation of injected carriers into semiconductors, in which the transfer of angular momentum from the electron spin to photon controls the circular polarization of the emitted light. The spin-photon conversion with the nonvolatile control of magnetization opens paths to seamlessly integrate information transfer, processing and storage. Our results provide substantial advances towards electrically controlled ultrafast modulation of circular polarization and spin injection with magnetization dynamics for the next-generation information and communication technology, including space-light data transfer. The same operating principle in scaled-down structures or using two-dimensional materials will enable transformative opportunities for quantum information processing with spin-controlled single-photon sources, as well as for implementing spin-dependent time-resolved spectroscopies.

74 ATOMIC AND MOLECULAR PHYSICS↗
NASA NTRS1967

Advanced space information systems

Onboard computers for pre-transmission data processing, automation of data acquisition centers, and real time data relay to control centers for advanced space information systems

REAL TIME↗
NASA NTRS1962

Advanced Environmental Systems

Atmosphere controls for advanced manned space vehicles will in some cases require techniques different from those selected as optimum for the Mercury environmental control system (ECS). Water conservation will be rigorous for vehicles which use a solar or nuclear auxiliary power unit (APU). For missions longer than a few hundred hours, CO2 will be removed in a regenerable process. Several promising regenerable CO2 removal systems are presented, including freeze-out. Regeneration of oxygen from C02 is discussed as the next step in atmosphere control advancement. Test work on CO2 hydrogenation by the Sabatier process is cited. The recommended makeup of ECS elements is presented as a function of mission duration.

Manned spacecraft↗
DOE OSTI2017

Advanced Control of Next Generation Offshore Wind Turbines

Advanced turbine controls and structural dampers have the potential to significantly reduce the cost of energy (CoE) for offshore wind turbines. Progress made in these two areas on a Department of Energy (DoE) funded program is reported. A lidar-assisted control strategy, with objective to reduce component loads and increase energy capture, is developed and implemented. The controller has been tested in both simulations and on a 3MW utility-scale prototype. The controller results indicate a significant reduction in the tower fatigue loads. In a parallel effort, potential of a passive and semi-active tuned-mass damper (TMD) is evaluated to mitigate fatigue and extreme loads. Simulation results with passive and semi-active TMD indicate significant load reduction for tower and substructure for both fixed-bottom and floating wind turbines. Finally, levelized cost of energy modeling process to account for benefits of advanced controls is discussed.

structural dampers. cost of energy, lidar-assisted↗
DOE OSTI2025

Chemical and Optical Control of Spin Crossover: Ultrafast XUV Spectroscopy of Molecular Magnets in Native Solvation Environments

With support from the US Department of Energy Office of Science, we have developed and utilized extreme ultraviolet (XUV) spectroscopy and sum frequency generation vibrational spectroscopy as probes of charge, spin, and solvation structure and dynamics in molecules and at interfaces. This work is crucial to advancing fundamental understanding of the processes that control the efficiency and speed of energy conversion and information processing in molecules and at interfaces. Accordingly, it has important applications for developing next generation technologies for information storage and processing with increasing data storage density and processing rates as well as developing new methods for efficient energy conversion and storage.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

I&C System Sensors for Advanced Nuclear Reactors

As advanced reactor designers proceed with further research, design implementation, testing, and deployment, it is now time to address their instrumentation and control (I&C) needs. First, we must identify the process variables that must be measured to control an advanced reactor and monitor its safety. As with any nuclear power plant, it is safe to assume that temperature, pressure, flow, level, and neutron flux are the predominant variables to be measured. As a second step, the range of process values must be established as well as the level of accuracy, redundancy, and speed of response of sensors that must be deployed to measure these values. The harsh environments of advanced reactors such as high temperatures, high levels of nuclear radiation, potential for corrosion, and limited access to sensors for maintenance are just a few examples of instrumentation challenges. This is compounded by the relatively small market for new sensors that must be designed, developed, and qualified for advanced reactors. That is, the cost of these activities can deter major sensor manufacturers from entering the advanced reactor market. Furthermore, the operating cycles of most advanced reactors are expected to be much longer than conventional plants adding to the need for instrumentation that can maintain calibration and response time over extended intervals. The fact that there are now a variety of advanced reactors under design and development adds to the complexity of instrumentation that may differ for various types of advanced plants. A few examples of the most commonly discussed advanced reactors are reviewed in this paper followed by a brief discussion of their instrumentation needs.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1989

DEVS representation of dynamical systems - Event-based intelligent control

It is shown how systems can be advantageously represented as discrete-event models by using DEVS (discrete-event system specification), a set-theoretic formalism. Such DEVS models provide a basis for the design of event-based logic control. In this control paradigm, the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by its DEVS model of the system under control. The event-based contral paradigm is applied in advanced robotic and intelligent automation, showing how classical process control can be readily interfaced with rule-based symbolic reasoning systems.

Zeigler, Bernard P.↗
DOE OSTI2022

PyZebrascope: An Open-Source Platform for Brain-Wide Neural Activity Imaging in Zebrafish

Understanding how neurons interact across the brain to control animal behaviors is one of the central goals in neuroscience. Recent developments in fluorescent microscopy and genetically-encoded calcium indicators led to the establishment of whole-brain imaging methods in zebrafish, which record neural activity across a brain-wide volume with single-cell resolution. Pioneering studies of whole-brain imaging used custom light-sheet microscopes, and their operation relied on commercially developed and maintained software not available globally. Hence it has been challenging to disseminate and develop the technology in the research community. Here, we present PyZebrascope, an open-source Python platform designed for neural activity imaging in zebrafish using light-sheet microscopy. PyZebrascope has intuitive user interfaces and supports essential features for whole-brain imaging, such as two orthogonal excitation beams and eye damage prevention. Its camera module can handle image data throughput of up to 800 MB/s from camera acquisition to file writing while maintaining stable CPU and memory usage. Its modular architecture allows the inclusion of advanced algorithms for microscope control and image processing. As a proof of concept, we implemented a novel automatic algorithm for maximizing the image resolution in the brain by precisely aligning the excitation beams to the image focal plane. PyZebrascope enables whole-brain neural activity imaging in fish behaving in a virtual reality environment. Thus, PyZebrascope will help disseminate and develop light-sheet microscopy techniques in the neuroscience community and advance our understanding of whole-brain neural dynamics during animal behaviors.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2002

Adopting Industry Standards for Control Systems Within Advanced Life Support

This paper gives a description of OPC (Object Linking and Embedding for Process Control) standards for process control and outlines the experiences at JSC with using these standards to interface with I/O hardware from three independent vendors. The I/O hardware was integrated with a commercially available SCADA/HMI software package to make up the control and monitoring system for the Environmental Systems Test Stand (ESTS). OPC standards were utilized for communicating with I/O hardware and the software was used for implementing monitoring, PC-based distributed control, and redundant data storage over an Ethernet physical layer using an embedded din-rail mounted PC.

Young, James Scott↗
DOE OSTI2023

Data-Driven Approaches for Bead Geometry Prediction Via Melt Pool Monitoring

In the realm of additive manufacturing, the selection of process parameters to avoid over and under deposition entails a time-consuming and resource-intensive trial-and-error approach. Given the distinct characteristics of each part geometry, there is a pressing need for advancing real-time process monitoring and control to ensure consistent and reliable part dimensional accuracy. Here, this research shows that support vector regression (SVR) and convolutional neural network (CNN) models offer a promising solution for real-time process control due to the models’ abilities to recognize complex, non-linear patterns with high accuracy. A novel experiment was designed to compare the performance of SVR and CNN models to indirectly detect bead height from a coaxial image of a melt pool from a single-layer, single bead build. The study showed that both SVR and CNN models trained on melt pool data collected from a coaxial optical camera can accurately predict the bead height with a mean absolute percentage error of 3.67% and 3.68%, respectively.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Internship Work Report

I worked on two projects during my summer internship at Sandia. My official title was “Intern - Mission Tech Electrical Eng./Computer Eng.- R&D Undergraduate Summer.” I worked at the central location, which is Albuquerque, New Mexico. The department you are placed in at Sandia doesn’t always correspond to the people you will be working with. For example, I only directly worked with one person from my department this summer. On one of my projects, I worked with a diverse team of engineers from many different departments. On my other project, I mainly worked with two departments, as the project had two distinct parts. As mentioned earlier, I worked on two projects during my summer at Sandia. The first project focused on a lightweight embedded controller in an advanced FPGA System-on-Chip for radar signal processing applications. The term “controller” refers to a hardware device that directs the flow of data between two entities. An FPGA is a reprogrammable integrated circuit (as opposed to an integrated circuit with one purpose). An FPGA was used on this project so in order to protype various ideas for our System-on-Chip. My role on the project was to implement designs on the fabric of the FPGA and design a state machine (written in C) for the processor. My second project was also heavily involved with embedded systems but had a different application. It focused on using a Newton-Raphson control algorithm to stabilize an inverted pendulum using a novel microcontroller. The pendulum dynamics were derived, and it was successfully simulated in MATLAB. I worked on integrating the microcontroller with the inverted pendulum machinery, and converting the Newton-Raphson control algorithm from MATLAB into C. The inverted pendulum was successfully stabilized using a simple PID controller and industry-standard microcontroller. The project is still ongoing, and the team is gearing up for more tests using the novel Newton-Raphson control algorithm and novel microcontroller

42 ENGINEERING↗
DOE OSTI2018

A biologically-inspired approach for adaptive control of advanced energy systems

Here in this article, a novel approach is proposed for integrating a Biologically-Inspired Optimal Control Strategy (BIOsingle bondCS) with an Artificial Neural Network (ANN)-based adaptive component for advanced energy systems applications. Specifically, BIOsingle bondCS employs gradient-based optimal control solvers in a biologically-inspired manner, following the rule of pursuit for ants, to simultaneously control multiple process outputs at their desired setpoints. Also, the ANN component captures the mismatch between the controller and the plant models by using a single-hidden-layer technique with online learning capabilities to augment the baseline BIOsingle bondCS control laws. The resulting approach is a unique combination of biomimetic control and data-driven methods that provides optimal solutions for dynamic systems. The applicability of the proposed framework is illustrated via an Integrated Gasification Combined Cycle (IGCC) process with carbon capture as an advanced energy system example. In particular, a multivariable control structure associated with a subsystem of the IGCC plant simulation in DYNSIM® is addressed. The proposed control laws are derived in MATLAB®, while the plant models are built in DYNSIM®, and a previously developed MATLAB®-DYNSIM® link is employed for implementation purposes. The proposed integrated approach improves the overall performance of the process up to 85% in terms of reducing the output tracking error when compared to stand-alone BIOsingle bondCS and Proportional-Integral (PI) controller implementations, resulting in faster setpoint tracking. The proposed framework thus provides a promising alternative for advanced control of energy systems of the future.

42 ENGINEERING↗