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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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-F-T-469: A Clinically Observed Discrepancy Between Image-Based and Log- Based MLC Position

Purpose: To present a clinical case which challenges the base assumption of log-file based QA, by showing that the actual position of a MLC leaf can suddenly deviate from its programmed and logged position by >1 mm as observed with real-time imaging. Methods: An EPID-based exit-fluence dosimetry system designed to prevent gross delivery errors was used in cine mode to capture portal images during treatment. Visual monitoring identified an anomalous MLC leaf pair gap not otherwise detected by the automatic position verification. The position of the erred leaf was measured on EPID images and log files were analyzed for the treatment in question, the prior day’s treatment, and for daily MLC test patterns acquired on those treatment days. Additional standard test patterns were used to quantify the leaf position. Results: Whereas the log file reported no difference between planned and recorded positions, image-based measurements showed the leaf to be 1.3±0.1 mm medial from the planned position. This offset was confirmed with the test pattern irradiations. Conclusion: It has been clinically observed that log-file derived leaf positions can differ from their actual positions by >1 mm, and therefore cannot be considered to be the actual leaf positions. This cautions the use of log-based methods for MLC or patient quality assurance without independent confirmation of log integrity. Frequent verification of MLC positions through independent means is a necessary precondition to trusting log file records. Intra-treatment EPID imaging provides a method to capture departures from MLC planned positions. Work was supported in part by Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-G-201-04: Can the Dynamic Library of Flap Applicators Replace Treatment Planning in Surface Brachytherapy?

Purpose: Contemporary brachytherapy treatment planning systems-(TPS) include the applicator model libraries to improve digitization; however, the library of surface-flap-applicators-(SFA) is not incorporated into the commercial TPS. We propose the dynamic library-(DL) for SFA and investigate if such library can eliminate applicator reconstruction, source activation and dose normalization. Methods: DL was generated for the SFA using the C++class libraries of the Visualization Toolkit-(VTK) and Qt-application framework for complete abstraction of the graphical interface. DL was designed such that the user can initially choose the size of the applicator that corresponds to the one clinically placed to the patient. The virtual applicator-(VA) has an elastic property so that it can be registered to the clinical CT images with a real applicator-(RA) on it. The VA and RA matching is performed by adjusting the position and curvature of the VA. The VA does not elongate or change its size so each catheter could always be at a distance of 5mm from the skin and 10mm apart from the closest catheter maintaining the physical accuracy of the clinical setup. Upon the applicator placement, the dwell positions were automatically activated, and the dose is normalized to the prescription depth. The accuracy of source positioning was evaluated using various applicator sizes. Results: The accuracy of the applicator placement was in the sub-millimeter range. The time-study reveals that up to 50% of the planning time can be saved depending on the complexity of the clinical setup. Unlike in the classic approach, the planning time was not highly dependent on the applicator size. Conclusion: The practical benefits of the DL of the SFA were demonstrated. The time demanding planning processes can be partially automated. Consequently, the planner can dedicate effort to fine tuning, which can result in the improvement of the quality of treatment plans in surface brachytherapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Three-dimensional printing of wood

Natural wood has served as a foundational material for buildings, furniture, and architectural structures for millennia, typically shaped through subtractive manufacturing techniques. However, this process often generates substantial wood waste, leading to material inefficiency and increased production costs. A potential opportunity arises if complex wood structures can be created through additive processes. Here, we demonstrate an additive-free, water-based ink made of lignin and cellulose, the primary building blocks of natural wood, that can be used to three-dimensional (3D) print architecturally designed wood structures via direct ink writing. The resulting printed structures, after heat treatment, closely resemble the visual, textural, olfactory, and macro-anisotropic properties, including mechanical properties, of natural wood. Our results pave the way for 3D-printed wooden construction with a sustainable pathway to upcycle/recycle natural wood.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Visualization of the impatiens downy mildew pathogen using fluorescence in situ hybridization (FISH)

Background: Plasmopara obducens is the biotrophic oomycete responsible for impatiens downy mildew, a destructive disease of Impatiens that causes high crop loss. Currently, there are no available methods for the microscopic detection of P. obducens from leaves of impatiens, which may be contributing to the spread of the disease. Fluorescence in situ hybridization (FISH) is a sensitive and robust method that uses sequence-specific, fluorescence-labeled oligonucleotide probes to detect target organisms from the environment. To study this important pathogen, we developed and standardized a FISH technique for the visualization of P. obducens from Impatiens walleriana tissues using a species-specific 24-mer oligonucleotide probe designed to target a region of the rRNA internal transcribed spacer 2 (ITS2). Results: Since P. obducens cannot be propagated in vitro, we developed a custom E. coli expression vector that transcribes the P. obducens rRNA-ITS target sequence (clone-FISH) for use as a control and to optimize hybridization conditions. The FISH assay could detect P. obducens sporangiophores, sporangia and oospores, and hyphae from naturally infected I. walleriana leaves and stems. Cross-reactivity was not observed from plant tissue, and the assay did not react when applied to E. coli with self-ligated plasmids and non-target oomycete species. Conclusions: This FISH protocol may provide a valuable tool for the study of this disease and could potentially be used to improve early monitoring of P. obducens , substantially reducing the persistence and spread of this destructive plant pathogen.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Gamma-ray imaging and holdup assays of 235-F PuFF cells 1 & 2

Savannah River National Laboratory (SRNL) Nuclear Measurements (L4120) was tasked with performing enhanced characterization of the holdup in the PuFF shielded cells. Assays were performed in accordance with L16.1-ADS-2460 using two high-resolution gamma-ray detectors. The first detector, an In Situ Object Counting System (ISOCS)-characterized detector, was used in conjunction with the ISOCS Geometry Composer software to quantify grams of holdup. The second detector, a Germanium Gamma-ray Imager (GeGI), was used to visualize the location and relative intensity of the holdup in the cells. Carts and collimators were specially designed to perform optimum assays of the cells. Thick, pencil-beam tungsten collimators were fabricated to allow for extremely precise targeting of items of interest inside the cells. Carts were designed with a wide range of motion to position and align the detectors. A total of 24 measurements were made, each typically 24 hours or longer to provide sufficient statistical precision. This report presents the results of the enhanced characterization for cells 1 and 2. The measured gram values agree very well with results from the 2014 study. In addition, images were created using both the 2014 data and the new GeGI data. The GeGI images of the cells walls reveal significant Pu-238 holdup on the surface of the walls in cells 1 and 2. Additionally, holdup is visible in the two pass-throughs from cell 1 to the wing cabinets. This report documents the final element (exterior measurements coupled with gamma-ray imaging and modeling) of the enhanced characterization of cells 1-5 (East Cell Line).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1975

Mount mechanisms for the Saturn 5/Apollo mobile launcher at John F. Kennedy Space Center

A support system was designed to resist hurricane wind loads at the launch pad and to allow the supported structural frame to expand and contract freely under wide ranges of temperature. This system consists of six mount mechanisms devised to meet the previously stated requirements plus a load-carrying capacity for each of 3.2-million kilograms (7-million pounds) downward and 1.6-million kilograms (3.5-million pounds) upward. A similar but lighter system of six mount mechanisms was designed for use in the sheltered environment of the vehicle assembly building. Each requirement and design result is discussed, and each mount mechanism is defined by location and type with references to visual presentations.

Balke, H. A.↗
NASA NTRS1985

Continuous prediction of Spartan visibility from Orbiter over modeled free-flight mission

Orbital operations in the neighborhood of other satellites or free-flying objects need the ability to see and detect such objects optically. This ability depends primarily on the brightness of the object relative to other sources present. The present analysis and computational procedure provides a means for predicting the visual brightness of a satellite when viewed from a nearby satellite in the same orbit. It is designed specifically for estimating the brightness of Spartan free-flyers from the STS Orbiters which release and later retrieve them, but the basic methods are applicable to other satellite-to-satellite visibility prediction problems. The Spartan reflector model defined herein is illuminated both by direct solar radiation and by the earth (albedo), producing a model source of defined directional intensity. The intensity in the Orbiter direction (along orbit) yields the desired maximum range directly. The required geometric and photometric calculations involve a number of angles in space, which are readily computed from the basic directions defining their sides. The time-dependent directions are determined by straightforward calculation from fundamental relationships and constants.

King, J. C.↗
NASA NTRS1987

Transonic flow visualization using holographic interferometry

An account is made of some of the applications of holographic interferometry to the visualization of transonic flows. In the case of the compressor shock visualization, the method is used regularly and has moved from being a research department invention to a design test tool. With the implementation of automatic processing and simple digitization systems, holographic vibrational analysis has also moved into routine nondestructive testing. The code verification interferograms were instructive, but the main turbomachinery interest is now in 3 dimensional flows. A major data interpretation effort will be required to compute tomographically the 3 dimensional flow around the leading or the trailing edges of a rotating blade row. The bolt on approach shows the potential application to current unsteady flows of interest. In particular that of the rotor passing and vortex interaction effects is experienced by the new generation of unducted fans. The turbocharger tests presents a new area for the application of holography.

Bryanston-Cross, Peter J.↗
NASA NTRS1986

A smoke-wire study of low Reynolds number flow over a NASA LRN(1) - 1007 airfoil section

Smoke-filament visualization photographs are presented for two-dimensional flow over a NASA LRN(1) - 1007 airfoil section designed specifically for high-efficiency operation at low chord Reynolds numbers. Results are included for chord Reynolds numbers of 60,000, 100,000, and 220,000 and for angles of attack ranging from 0 to 16 degrees. Two kinds of laminar separation bubble are found to develop in the flow over the airfoil. The sites and characteristics of formation of these bubbles are described, and their dimensional properties are estimated. The transition-to-turbulence Reynolds numbers, surface pressure coefficient distributions, and lift coefficients deduced from the measured coefficients are compared with those obtained by other authors.

Fisher, S. S.↗
NASA NTRS1990

EVA/manned systems

Viewgraphs on extravehicular activity/manned systems are presented. Objectives of crewstation design include (1) development of human-computer interface technology and graphical presentations, including multi-dimensional visual and aural displays; (2) provide a technology base for autonomous vision and other perceptual systems, virtual workstation technology, and computational vision systems; and (3) develop databases and models of human strength, motion, and body positions in microgravity environments. Extravehicular technology is addressed.

Jenkins, James P.↗
NASA NTRS1992

Multiresolution image gathering and restoration

In this paper we integrate multiresolution decomposition with image gathering and restoration. This integration leads to a Wiener-matrix filter that accounts for the aliasing, blurring, and noise in image gathering, together with the digital filtering and decimation in signal decomposition. Moreover, as implemented here, the Wiener-matrix filter completely suppresses the blurring and raster effects of the image-display device. We demonstrate that this filter can significantly improve the fidelity and visual quality produced by conventional image reconstruction. The extent of this improvement, in turn, depends on the design of the image-gathering device.

Fales, Carl L.↗
NASA NTRS1961

Analysis of Effects of Interceptor Roll Performance and Maneuverability on Success of Collision-Course Attack

An attempt has been made to determine the importance of rolling performance and other factors in the design of an interceptor which uses collision-course tactics. A graphical method is presented for simple visualization of attack situations. By means of diagrams showing vectoring limits, that is, the ranges of interceptor position and heading from which attacks may be successfully completed, the relative importance of rolling performance and normal-acceleration capability in determining the success of attacks is illustrated. The results indicate that the reduction in success of attacks due to reduced rolling performance (within the limits generally acceptable from the pilots' standpoint) is very small, whereas the benefits due to substantially increasing the normal-acceleration capability are large. Additional brief analyses show that the optimum speed for initiating a head-on attack is often that corresponding to the upper left-hand corner of the V-g diagram. In these cases, increasing speed beyond this point for given values of normal acceleration and radar range rapidly decreases the width of the region from which successful attacks can be initiated. On the other hand, if the radar range is increased with a variation somewhere between the first and second power of the interceptor speed, the linear dimensions of the region from which successful attacks can be initiated vary as the square of the interceptor speed.

Phillips, William H.↗
NASA NTRS2011

Experimental Investigation of a Large-Scale Low-Boom Inlet Concept

A large-scale low-boom inlet concept was tested in the NASA Glenn Research Center 8- x 6- foot Supersonic Wind Tunnel. The purpose of this test was to assess inlet performance, stability and operability at various Mach numbers and angles of attack. During this effort, two models were tested: a dual stream inlet designed to mimic potential aircraft flight hardware integrating a high-flow bypass stream; and a single stream inlet designed to study a configuration with a zero-degree external cowl angle and to permit surface visualization of the vortex generator flow on the internal centerbody surface. During the course of the test, the low-boom inlet concept was demonstrated to have high recovery, excellent buzz margin, and high operability. This paper will provide an overview of the setup, show a brief comparison of the dual stream and single stream inlet results, and examine the dual stream inlet characteristics.

Hirt, Stefanie M.↗
NASA NTRS2019

eddy Users Manual

eddy is a collection of tools - nonlinear solvers, meshing, post-processing, visualization, optimization, etc. - for performing scale-resolving simulations of multi-physics applications. The framework is designed to enable advanced R&D on a variety of topics by leveraging a mature capability for scale resolving simulations, and simultaneously be an appropriate tool for application analysis and support. Currently, eddy is at a relatively low technical readiness level (TRL), and users and developers should maintain appropriate expectations. The technical details behind eddy are outlined in several publications which can be consulted for more information [1–10]. The solvers are built around an unstructured high-order capability, and heavily utilize the tensor product sum-factorization approach for efficiency. The unsteady formulation utilizes a fully implicit space-time approach with a matrix-free Newton- Krylov method. A primitive steady-state solver is available for testing purposes, but is not expected to converge for all but simple verification cases. The Navier-Stokes fluid solvers do not support either RANS or hybrid-RANS capability, only LES and wall-modeled LES approaches. All of the solvers within eddy support three modes of operation: a primal solve of the full nonlinear problem, and two linearization approaches of the primal solve - the ad joint and the tangent solution. Details on how to select and use these three modes are outlined in Sec. 3.

Murman, Scott M.↗
DOE OSTI2021

Occupancy-Driven Stochastic Decision Framework for Ranking Commercial Building Loads

For effective integration of building operations into the evolving demand response programs of the power grid, real-time decisions concerning the use of building appliances for grid services must excel on multiple criteria, ranging from the added value to occupants' comfort to the quality of the grid services. In this paper, we present a data-driven stochastic decision-support framework to dynamically rank load control alternatives in a commercial building, addressing the needs of multiple decision criteria (e.g. occupant comfort, grid service quality) under uncertainties in occupancy patterns. We adopt a stochastic multi-criteria decision algorithm recently applied to prioritize residential on/off loads, and extend it to i) consider complex load control decisions (e.g. dimming of lights, changing zone temperature set-points) in a commercial building; and ii) systematically integrate zonal occupancy patterns to better identify short-term (and time-varying) opportunities for grid service participation. We evaluate the performance of the proposed framework for curtailment of air-conditioning, lighting, and plug-loads in a multi-zone commercial office building for a range of design choices. With the help of a prototype system that integrates an interactive \textit{Data Analytics and Visualization} frontend we demonstrate a way for the building operators to monitor and change in real-time the available flexibility in energy consumption and to develop trust in the decision recommendations by interpreting the rationale behind the ranking.

Jain, Milan↗
DOE OSTI2014

TU-F-17A-01: BEST IN PHYSICS (JOINT IMAGING-THERAPY) - An Automatic Toolkit for Efficient and Robust Analysis of 4D Respiratory Motion

Purpose: To provide an automatic image analysis toolkit to process thoracic 4-dimensional computed tomography (4DCT) and extract patient-specific motion information to facilitate investigational or clinical use of 4DCT. Methods: We developed an automatic toolkit in MATLAB to overcome the extra workload from the time dimension in 4DCT. This toolkit employs image/signal processing, computer vision, and machine learning methods to visualize, segment, register, and characterize lung 4DCT automatically or interactively. A fully-automated 3D lung segmentation algorithm was designed and 4D lung segmentation was achieved in batch mode. Voxel counting was used to calculate volume variations of the torso, lung and its air component, and local volume changes at the diaphragm and chest wall to characterize breathing pattern. Segmented lung volumes in 12 patients are compared with those from a treatment planning system (TPS). Voxel conversion was introduced from CT# to other physical parameters, such as gravity-induced pressure, to create a secondary 4D image. A demon algorithm was applied in deformable image registration and motion trajectories were extracted automatically. Calculated motion parameters were plotted with various templates. Machine learning algorithms, such as Naive Bayes and random forests, were implemented to study respiratory motion. This toolkit is complementary to and will be integrated with the Computational Environment for Radiotherapy Research (CERR). Results: The automatic 4D image/data processing toolkit provides a platform for analysis of 4D images and datasets. It processes 4D data automatically in batch mode and provides interactive visual verification for manual adjustments. The discrepancy in lung volume calculation between this and the TPS is <±2% and the time saving is by 1–2 orders of magnitude. Conclusion: A framework of 4D toolkit has been developed to analyze thoracic 4DCT automatically or interactively, facilitating both investigational and clinical use. More software tools are under development for automatic analysis of other 4D imaging modalities. This research is in part supported by NIH (U54CA137788/132378) and City Seed FY13(Grant No. 93348-14 01). AY would like to thank MSKCC summer medical student research program supported by National Cancer Institute and hosted by Department of Medical Physics at MSKCC.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2007

Experimental Design for the Evaluation of Detection Techniques of Hidden Corrosion Beneath the Thermal Protective System of the Space Shuttle Orbiter

The detection of corrosion beneath Space Shuttle Orbiter thermal protective system is traditionally accomplished by removing the Reusable Surface Insulation tiles and performing a visual inspection of the aluminum substrate and corrosion protection system. This process is time consuming and has the potential to damage high cost tiles. To evaluate non-intrusive NDE methods, a Proof of Concept (PoC) experiment was designed and test panels were manufactured. The objective of the test plan was three-fold: establish the ability to detect corrosion hidden from view by tiles; determine the key factor affecting detectability; roughly quantify the detection threshold. The plan consisted of artificially inducing dimensionally controlled corrosion spots in two panels and rebonding tile over the spots to model the thermal protective system of the orbiter. The corrosion spot diameter ranged from 0.100" to 0.600" inches and the depth ranged from 0.003" to 0.020". One panel consisted of a complete factorial array of corrosion spots with and without tile coverage. The second panel consisted of randomized factorial points replicated and hidden by tile. Conventional methods such as ultrasonics, infrared, eddy current and microwave methods have shortcomings. Ultrasonics and IR cannot sufficiently penetrate the tiles, while eddy current and microwaves have inadequate resolution. As such, the panels were interrogated using Backscatter Radiography and Terahertz Imaging. The terahertz system successfully detected artificially induced corrosion spots under orbiter tile and functional testing is in-work in preparation for implementation.

Kemmerer, Catherine C.↗
DOE OSTI2019

Small-Signal Modeling and Design of Phase-Locked Loops Using Harmonic Signal-Flow Graphs

This report introduces signal-flow graphs for linear time-periodic systems to streamline and visually describe the frequency-domain modeling of complex phase-locked loop (PLL) systems used in grid-connected converters. Small-signal modeling using the proposed graphs is demonstrated for two commonly used single-phase PLL structures: SOGI-PLL and Park-PLL. Loop-gain models are developed for these PLLs to evaluate how an orthogonal signal generator (OSG), which is required in single-phase PLLs using the synchronous reference frame (SRF) architecture, modifies the PLL loop-gain compared to that of a three-phase SRF-PLL, which does not require an OSG. It is shown that the OSG in the SOGI-PLL and Park-PLL introduces significant phase-lag in the PLL loop-gain, limiting the maximum bandwidth for which either PLL can be designed. Slow frequency adaptation (SFA) of OSG is proposed as a solution to mitigate the influence of the OSG dynamics on the PLL loop-gain. Experimental results are presented to validate the developed loop-gain models and show that the proposed SFA-SOGI-PLL and SFA-Park-PLL have improved transient performance, they do not suffer from the bandwidth limit, and they also preserve the steady-state performance of the standard SOGI-PLL and Park-PLL.

24 POWER TRANSMISSION AND DISTRIBUTION↗