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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Program control in NASA: Needs and opportunities

NASA has successfully managed some of this country's most complex technology and development programs. These successes have included the application of sound program control processes. The impetus for this study arose from the NASA Management Study Group findings that over time, some program control tools and disciplined procedures and processes had weakened. The Study Group recommended that steps be taken to establish a comprehensive training approach in program management, and specifically, in program control functions. This study looks at program control processes within NASA currently in use, defines a 'model' of program control functions, and provides recommendations on program control training needs and opportunities.

Lilly, William E.↗
DOE OSTI2019

Understanding and Controlling Cesium Loading on Crystalline Silicotitanate - 19601

Savannah River Remediation (SRR) contracted with Westinghouse Electric Corporation (WEC), Columbia Energy and Environmental Services (CEES), to build and deliver a modular ion exchange process that will be used to remove radioactive cesium from dissolved salt solution contained in Tank 10 at the Savannah River Site (SRS). The resulting decontaminated salt solution will be sent to Tank 11 and then to Tank 50 for final disposition in grout at the Saltstone facility. At the end of processing, the loaded ion exchange (IX) columns are drained, rinsed, and dried. The IX columns are removed from the modular unit and stored at Interim Safe Storage (ISS). This ion exchange process is called the Tank Closure Cesium Removal (TCCR) system. The TCCR system consists of several unit operations and process monitoring capability housed within three modular units. The first modular unit contains the process control computer, the second modular unit contains the main process equipment (two prefilters, four IX columns, and resin trap (post filtration)), and the third modular unit is the ventilation system. The main unit operations of the TCCR system are filtration, ion exchange, and ventilation. The ion exchange media utilized is a form of inorganic Crystalline Silicotitanate (CST), IONSIV{sup TM} R9120-B supplied by UOP Honeywell. CST has a high selectivity for cesium (Cs) and has some affinity for other Group IA alkali metals on the periodic chart (hydrogen, lithium, sodium, potassium, rubidium, and francium). CST has also been shown to have affinity for strontium and actinides. Cesium loading on the CST is dependent on many factors including chemical composition (cations and anions), temperature, and pH of the salt solution. The actual amount of Cs loaded onto an IX column is dependent on the factors above along with the salt solution volume fed to the IX column. Because of CST's high selectivity for Cs, the Cs-137 equilibrium loading can contribute enough decay heat to result in an ion exchange column boiling event under no flow conditions in the IX column. The boiling event under no flow is a safety concern that must be prevented from occurring. To prevent boiling of the column under no flow conditions, the Cs-137 equilibrium loading must be determined and understood. Several methodologies were evaluated for performing the Cs-137 equilibrium loading determination for CST. After review of available research and development (R and D), batch equilibrium contact test data, and Zheng Anthony Miller (ZAM) model predictions for the salt solution chemistry in Tank 10, a methodology for determining the Cs-137 equilibrium loading on CST was selected. The methodology selected involves an in-tank batch equilibrium contact test performed in duplicate that considers additional corrections to account for anticipated operational evolutions. The in-tank batch equilibrium contact test utilizes ∼0.1 grams of CST secured in a slotted sample vial. The slotted sample vial design allows for salt solution to be in contact with the CST. The slotted sample vials containing the CST are submerged in Tank 10 and exposed to the salt solution for ten days. After ten days, the samples are retrieved and sent to the Savannah River National Laboratory (SRNL) for analysis of the Cs-137 equilibrium loading. Additional corrections are then made to the Cs-137 results to account for anticipated operational evolutions. Anticipated operational evolutions include external additions (water/caustic) to Tank 10 that result in a change to its chemical composition, tank temperature effects, departures from the laboratory testing (mixed vs. stagnant tank conditions), and IX column flushes. A description of the methodologies considered, feasibility of methodology deployment, and the down select process (benefits vs. risks) is discussed in this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Virtual Control Systems Environment (VCSE)

Will Atkins, a Sandia National Laboratories computer engineer discusses cybersecurity research work for process control systems. Will explains his work on the Virtual Control Systems Environment project to develop a modeling and simulation framework of the U.S. electric grid in order to study and mitigate possible cyberattacks on infrastructure.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2011

TESTING OF THE DUAL ROTARY FILTER SYSTEM

The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be an issue in deployment where the desired flow rate will be within the normal operating range of the meter. Testing demonstrated that the use of a flexible line for the filtrate discharge is highly desired at the outlet of the rotary union to transition to the system piping. Isolating the vibration from the rotary union will significantly improve the lifetime of the seals. Methods to monitor and isolate individual filters should be considered during deployment. The ability to diagnose issues and isolate individual filters would allow isolation prior to failure. Thus, filters may be cleaned or repaired instead of requiring complete replacement if the condition were to continue unnoticed. Isolating the filtrate line of each filter during startup will minimize the premature buildup of solids on the filter disks. Several tests have shown that the method of filter startup can improve performance lifetime of the filters. The installation must factor in an air inlet for the draining of a filter that does not involve a reverse flow through the filter disks. The reverse flow may cause deformation of the disks or may damage other components of the filters themselves.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2005

Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates

Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed.

Perry, J. L.↗
DOE OSTI2020

Application of Koopman operator for model-based control of fracture propagation and proppant transport in hydraulic fracturing operation

This work explores the application of the recently developed Koopman operator approach for model identification and feedback control of a hydraulic fracturing process. Controlling fracture propagation and proppant transport with precision is a challenge due in large part to the difficulty of constructing approximate models that accurately capture the characteristic moving boundary and highly-coupled dynamics exhibited by the process. Koopman operator theory is particularly attractive here as it offers a way to explicitly construct linear representations for even highly nonlinear dynamics. The method is data-driven and relies on lifting the states to an infinite-dimensional space of functions called observables where the dynamics are governed by a linear Koopman operator. Here this work considers two problems: (a) fracture geometry control, and (b) proppant concentration control. In both cases, an approximate linear model of the corresponding dynamics is constructed and used to design a model predictive controller (MPC). The manuscript shows that in the case of highly nonlinear dynamics, as observed in the proppant concentration, use of canonical functions in the observable basis fails. In such cases, a priori system knowledge can be leveraged to choose the required basis. The numerical experiments demonstrate that the Koopman linear model shows excellent agreement with the real system and successfully achieves the desired target values maximizing the oil and gas productivity. Additionally, due to its linear structure, the Koopman models allow convex MPC formulations that avoid any issues associated with nonlinear optimization.

42 ENGINEERING↗
NASA NTRS2001

Shift changes, updates, and the on-call architecture in space shuttle mission control

In domains such as nuclear power, industrial process control, and space shuttle mission control, there is increased interest in reducing personnel during nominal operations. An essential element in maintaining safe operations in high risk environments with this 'on-call' organizational architecture is to understand how to bring called-in practitioners up to speed quickly during escalating situations. Targeted field observations were conducted to investigate what it means to update a supervisory controller on the status of a continuous, anomaly-driven process in a complex, distributed environment. Sixteen shift changes, or handovers, at the NASA Johnson Space Center were observed during the STS-76 Space Shuttle mission. The findings from this observational study highlight the importance of prior knowledge in the updates and demonstrate how missing updates can leave flight controllers vulnerable to being unprepared. Implications for mitigating risk in the transition to 'on-call' architectures are discussed.

Non-NASA Center↗
NASA NTRS1998

Taguchi Method Applied in Optimization of Shipley SJR 5740 Positive Resist Deposition

Taguchi Methods of Robust Design presents a way to optimize output process performance through an organized set of experiments by using orthogonal arrays. Analysis of variance and signal-to-noise ratio is used to evaluate the contribution of each of the process controllable parameters in the realization of the process optimization. In the photoresist deposition process, there are numerous controllable parameters that can affect the surface quality and thickness of the final photoresist layer.

Taguchi Method Shipley SJR 5740 orthogonal arrays ↗
DOE OSTI2015

SU-E-T-136: Assessment of Seasonal Linear Accelerator Output Variations and Associated Impacts

Purpose: Application of process control theory in quality assurance programs promises to allow earlier identification of problems and potentially better quality in delivery than traditional paradigms based primarily on tolerances and action levels. The purpose of this project was to characterize underlying seasonal variations in linear accelerator output that can be used to improve performance or trigger preemptive maintenance. Methods: Review of runtime plots of daily (6 MV) output data acquired using in house ion chamber based devices over three years and for fifteen linear accelerators of varying make and model were evaluated. Shifts in output due to known interventions with the machines were subtracted from the data to model an uncorrected scenario for each linear accelerator. Observable linear trends were also removed from the data prior to evaluation of periodic variations. Results: Runtime plots of output revealed sinusoidal, seasonal variations that were consistent across all units, irrespective of manufacturer, model or age of machine. The average amplitude of the variation was on the order of 1%. Peak and minimum variations were found to correspond to early April and September, respectively. Approximately 48% of output adjustments made over the period examined were potentially avoidable if baseline levels had corresponded to the mean output, rather than to points near a peak or valley. Linear trends were observed for three of the fifteen units, with annual increases in output ranging from 2–3%. Conclusion: Characterization of cyclical seasonal trends allows for better separation of potentially innate accelerator behaviour from other behaviours (e.g. linear trends) that may be better described as true out of control states (i.e. non-stochastic deviations from otherwise expected behavior) and could indicate service requirements. Results also pointed to an optimal setpoint for accelerators such that output of machines is maintained within set tolerances and interventions are required less frequently.

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS2002

Statistical porcess control in Deep Space Network operation

This report describes how the Deep Space Mission System (DSMS) Operations Program Office at the Jet Propulsion Laboratory's (EL) uses Statistical Process Control (SPC) to monitor performance and evaluate initiatives for improving processes on the National Aeronautics and Space Administration's (NASA) Deep Space Network (DSN).

Deep Space Network operations statistical process ↗
DOE OSTI2017

LLNL SFA OBER SBR FY17 Program Management and Performance Report: Subsurface Biogeochemistry of Actinides

A major scientific challenge in environmental sciences is to identify the dominant processes controlling actinide transport in the environment. It is estimated that currently, over 2200 metric tons of anthropogenic plutonium (Pu) has accumulated worldwide, a number that increases yearly with additional spent nuclear fuel (Ewing et al., 2010). Plutonium has been shown to migrate on the scale of kilometers, giving way to a critical concern that the fundamental biogeochemical processes that control its behavior in the subsurface are not well understood (Kersting et al. 1999; Novikov et al. 2006; Santschi et al. 2002). Neptunium (Np) is less prevalent in the environment; however, it is predicted to be a significant long-term dose contributor in high-level nuclear waste. Our focus on Np chemistry in this Science Plan is intended to help formulate a better understanding of Pu redox transformations in the environment and clarify the differences between the two long-lived actinides. The research approach of our Science Plan combines (1) Fundamental Mechanistic Studies that identify and quantify biogeochemical processes that control actinide behavior in solution and on solids, (2) Field Integration Studies that investigate the transport characteristics of Pu and test our conceptual understanding of actinide transport, and (3) Actinide Research Capabilities that allow us to achieve the objectives of this Scientific Focus Area (SFA) and provide new opportunities for advancing actinide environmental chemistry. These three Research Thrusts form the basis of our SFA Science Program.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2018

Graphics processing unit management system for computed tomography

A method and apparatus for managing operation of graphics processing units in a computer system. A processing thread in the computer system controls processing of a set of sinogram data by a graphics processing unit to form a set of graphics data. An output thread in the computer system controls writing of the set of graphics data to a storage system. The graphics processing unit is available to perform processing of another set of sonogram data while the set of graphics data is written to the storage system such that the increased availability of a plurality of graphics processing units is present.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Analysis of predicted mean vote-based model predictive control for residential HVAC systems

Model Predictive Control (MPC) is an advanced process control method that has attracted much attention in building heating, ventilation, and air conditioning (HVAC) systems. Here, this paper analyzes the optimal precooling performance in residential buildings using MPC with two different comfort indices, namely, temperature and predicted mean vote (PMV). It first formulates, for each comfort index, an optimization problem that accounts for different factors, such as weather, home thermal condition, prediction horizon, time-of use (TOU) utility rate, and rated cooling capacity. The problem is then solved, resulting in an MPC strategy that determines the HVAC on/off control signal and minimizes energy cost over a receding time horizon while maintaining thermal comfort. The energy performance difference between temperature-based and PMV-based MPC strategies is subsequently investigated, especially in light of the interior wall surface temperature and under different combinations of the factors. Extensive simulation results demonstrated that the proposed MPC strategies are adaptive and their performances depend primarily on weather, home thermal condition, and prediction horizon, while the impact of TOU utility rate and rated cooling capacity is relatively small. Because the PMV-based MPC strategy can take advantage of the lower interior wall surface temperature due to precooling, it resulted in 8–45% cost savings for the scenarios investigated and an average increase of 0.042–0.113 in the absolute value of the PMV index compared to the temperature-based MPC strategy.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Myna: Connecting powder bed fusion build data to simulation tools for digital twin applications

Additive manufacturing (AM), as a digital process, can generate a detailed digital thread linking a part’s design and manufacturing to its operational performance. As AM systems advance, an increasing amount of process data is stored in manufacturing databases. In principle, this data can be utilized by simulation-based digital twin approaches, such as real-time process control and asynchronous post-processing guidance. However, few tools currently exist for systematically integrating digital thread data with computational tools. Here, in this study, we propose a software package, called Myna, for connecting data from powder bed fusion processes to simulation tools. The utility of such a platform is demonstrated using build data from the Oak Ridge National Laboratory Manufacturing Demonstration Facility “Peregrine v2023-10” public dataset to automatically configure and run 54 semi-analytical 3DThesis melt pool simulations, 78 numerical Additive FOAM melt pool simulations, and 3 ExaCA microstructure simulations. The simulated, spatially registered microstructures are then compared directly with electron backscatter diffraction characterization of the corresponding as-built part locations. The resulting simulated microstructure showed variation as a function of process parameters, particularly stripe width; however, the experimental data had little variation between the microstructure texture and grain size resulting from different processing conditions. Analysis of the discrepancies suggest that it is possible a two-phase ferritic-austenitic solidification model is needed to accurately predict grain size and texture for certain stainless steel 316L feedstock compositions under powder bed fusion conditions, providing direction for future research. As illustrated here, due to the number and complexity of the simulations involved in AM process-structure–property predictions, automated methods to connect process data and simulations will remain necessary tools for testing hypotheses and implementing digital twin applications.

Knapp, Gerald L. [Oak Ridge National Laboratory (O↗
DOE OSTI2026

Multilevel Analysis of Electrochemically Mediated Methanolysis of Poly(ethylene terephthalate) (PET)

Here, this study presents a multilevel analysis of electrochemically mediated methanolysis as a promising method for reducing the environmental impacts of plastic recycling, with a focus on depolymerizing poly(ethylene terephthalate) (PET) into dimethyl terephthalate (DMT). Instead of conventional chemical PET depolymerization, this electrochemical approach provides distinct technical advantages in process control and efficiency. At the process level, key operational parameters, including applied current and reaction time, were systematically investigated to optimize PET conversion and DMT selectivity. The electrochemical approach was directly compared to equivalent chemical methanolysis systems and demonstrated superior performance in terms of PET conversion and DMT selectivity. Building on these findings, a technoeconomic assessment identified the current economic bottlenecks and revealed that improvements in process design, DMT selectivity, PET conversion, and energy efficiency are key to reducing the overall process cost and enabling future implementation. While further optimization is required for market competitiveness, these results establish a performance baseline for the electrochemically mediated PET methanolysis process and underscore the importance of combining process-level innovation with systems-level evaluation in the development of sustainable recycling technologies.

chemical recycling↗