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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

LABQ3: Bayesian method for quantification of mineral compositions and nano-scale elemental mapping of 3D synchrotron XCT data

Quantitative analysis of mineral compositions is essential in understanding geochemical, mineralogical and environmental processes. Fine-resolution 3D imaging is widely done using synchrotron X-ray computed tomography (XCT), but existing analyses are limited to visualization and segmentation. This paper presents a new method, Linear Attenuation Bayesian Quantitative 3D-mapper (LABQ3), based on the linearity of X-ray attenuation with respect to elemental concentrations. To address the random variability in attenuation measurements, LABQ3 employs Bayesian decision theory to minimize classification error, using reference attenuation distributions from scans of pure mineral standards. To demonstrate LABQ3 and test its performance, we studied precipitated carbonate samples. XCT scans were done at multiple energies using the transmission X-ray microscope (TXM) at beamline 32-ID-C of the Advanced Photon Source at Argonne National Laboratory. The reconstructed 3D images have a voxel size of 20 nm. Analyses revealed rich nano-scale compositional heterogeneity within individual particles. A mixture of calcium and cadmium produced an overall stoichiometric composition of (Ca 0.78 ,Cd 0.22 )CO 3 , with some voxels containing nearly pure CdCO 3 . The addition of zinc led to an overall stoichiometric composition of 33% Ca, 28% Cd, 39% Zn, with a nearly pure CaCO 3 core and compositional zonation through the rim. These compositional gradients are related to temporal sequences of carbonate mineral formation where Cd precipitated at the beginning in (Ca,Cd)CO 3 , while Cd and Zn precipitated at the end in (Ca, Cd,Zn)CO 3 . Results differ from bulk analyses using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), showing that LABQ3 provides particle-specific insights. LABQ3 distinguishes itself by quantifying chemical compositions along a continuum, making it different from XCT analyses based on segmentation. LABQ3 allows simultaneous acquisition of morphology and chemical composition in 3D, facilitating the interpretation of chemical gradients of trace elements, quantification of solid solution compositions, inferences about temporal sequences of mineral precipitation, and addressing other concerns about solid-phase chemistry.

58 GEOSCIENCES↗
DOE OSTI2018

3D Visualisation of Un-georeferenced, Coordinate-poor Spatial Data in Complex D and D and WM Environments - 18294

This paper describes the development of an algorithm-based utility tool using Visual Basic that examines un-georeferenced or GPS-deprived spatial datasets (3D datasets lacking one or more of the key x, y and z components). Taking into account any known geometrical parameters which are input via a user-friendly front-end, the new code automatically evaluates attributes, including any spatial coordinate components, detects invalid survey data points and fills in bad or missing data points utilising data-specific interpolation (e.g. cubic or linear spline) of valid data points, such that local extrema are not created. Previously troublesome 2D data can be easily converted to realistic 3D contour display, integrated with other time-series data to create 4D movies, and incorporated into other existing 3D datasets. More importantly those processed and 'more complete' data can be easily stored in 3D or 4D spatial database management systems for future interrogation by using clear, realistic and intuitive 3D visualisation. Test cases are presented to demonstrate the value and versatility of the newly developed utility tool which include the 3D visualisation of: surveyed wall thicknesses of a helical coil, radiation mapping of a plant and aerial survey mapping of radiation in a region near Fukushima. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

An MCNP6 Version of the Visual Editor - Paper 2

The Visual Editor is a graphical user interface for working with the MCNP computer code developed at Los Alamos National Laboratory. It consists of a graphical user interface written in C++ that is linked directory to the MCNP Fortran code. Work on the original Visual Editor started in 1992 and was first published in 1993. The original version of the Visual Editor was created on Unix/Linux operating systems and was linked to the MCNP computer code. The Visual Editor was adapted to the Windows operating system in 1999. In 2008 the Visual Editor was adapted to work with the MCNPX computer code. This paper discusses the latest upgrade of the Visual Editor to be compatible with the MCNP6 computer code. Two graphical user interfaces have been created, the Visual MCNP6 Plotter and the Visual MCNP6 Editor. The Visual MCNP6 Plotter includes all of the standard plotting features available in the default MCNP6 plotting package including geometry plotting, tally plotting, cross section plotting, mesh tally plotting and weight window mesh plotting. The Visual MNCP6 Editor has additional capabilities to allow for the creation of MCNP input files with graphical tools. The Visual MCNP6 Editor allows user to create and modify the input file within the Editor. Modifications are not allowed in the Visual MCNP6 Plotter. Both graphical user interfaces allow for advanced plotting features including 3D geometry plots and particle track plotting. Complete details on these tools along with their current status can be found at the Visual Editor website (www.mcnpvised.com). (author)

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2016

TH-EF-BRA-11: Feasibility of Super-Resolution Time-Resolved 4DMRI for Multi-Breath Volumetric Motion Simulation in Radiotherapy Planning

Purpose: To develop a novel super-resolution time-resolved 4DMRI technique to evaluate multi-breath, irregular and complex organ motion without respiratory surrogate for radiotherapy planning. Methods: The super-resolution time-resolved (TR) 4DMRI approach combines a series of low-resolution 3D cine MRI images acquired during free breathing (FB) with a high-resolution breath-hold (BH) 3DMRI via deformable image registration (DIR). Five volunteers participated in the study under an IRB-approved protocol. The 3D cine images with voxel size of 5×5×5 mm{sup 3} at two volumes per second (2Hz) were acquired coronally using a T1 fast field echo sequence, half-scan (0.8) acceleration, and SENSE (3) parallel imaging. Phase-encoding was set in the lateral direction to minimize motion artifacts. The BH image with voxel size of 2×2×2 mm{sup 3} was acquired using the same sequence within 10 seconds. A demons-based DIR program was employed to produce super-resolution 2Hz 4DMRI. Registration quality was visually assessed using difference images between TR 4DMRI and 3D cine and quantitatively assessed using average voxel correlation. The fidelity of the 3D cine images was assessed using a gel phantom and a 1D motion platform by comparing mobile and static images. Results: Owing to voxel intensity similarity using the same MRI scanning sequence, accurate DIR between FB and BH images is achieved. The voxel correlations between 3D cine and TR 4DMRI are greater than 0.92 in all cases and the difference images illustrate minimal residual error with little systematic patterns. The 3D cine images of the mobile gel phantom preserve object geometry with minimal scanning artifacts. Conclusion: The super-resolution time-resolved 4DMRI technique has been achieved via DIR, providing a potential solution for multi-breath motion assessment. Accurate DIR mapping has been achieved to map high-resolution BH images to low-resolution FB images, producing 2Hz volumetric high-resolution 4DMRI. Further validation and improvement are still required prior to clinical applications. This study is in part supported by the NIH (U54CA137788/U54CA132378).

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Understanding Dynamical Systems in High-Dimensional Parameter Spaces (Final Report)

In the last few decades, computational models, especially of the complex dynamical systems of greatest interest, i.e., climate, high energy density science, combustion, etc. have become increasingly accurate and sophisticated. Consequently, they are now routinely used to predict outcomes of experiments or to inform design decisions. However, many such simulations depend on a (large) number of parameters in order to, for example, approximate physical phenom whose exact solution is unknown or describe material properties in situations with little or no experimental data. Choosing these parameters and understanding how the outcomes of such a simulation changes with respect to the inputs are rapidly becoming some of the primary challenges in many application areas. Simulations have long been too complex for humans to fully comprehend and thus are often treated as black-box systems. The inputs to the systems are typically a collection of parameters with expert-selected ranges, and the outputs are various quantities of interest (QoIs) describing the performance of the system. Therefore, the fundamental challenge can be described as one of understanding a high-dimensional (many input parameters), multi-variate (many QoIs) function. Unfortunately, existing analysis tools are only of limited use for this task as most techniques can neither deal with many input dimensions nor offer opportunities to jointly study several QoIs. Furthermore, data analysis has long relied on an exploratory process in which scientist first visualize the available data, for example, using scatter plots or 3D renderings, form new hypotheses on some phenomena of interest, and subsequently test these hypotheses using dedicated analysis or statistics approaches. However, for high-dimensional functions this exploration is difficult if not impossible using existing tools as there are too many QoIs to simultaneously observe, and visualizations of high-dimensional spaces are abstract and difficult to understand if they exist at all. The goal of this project is to build new analysis techniques and tool that offer high level insights for exploring high-dimensional scientific data. And to extend existing approach beyond single scalar functions and instead consider multiple QoIs simultaneously.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

TU-H-CAMPUS-IeP2-05: Breast and Soft Tissue-Equivalent 3D Printed Phantoms for Imaging and Dosimetry

Purpose: The study has the goal to demonstrate that breast and soft tissue-equivalent phantoms for dosimetry applications in the diagnostic energy range can be fabricated using common 3D printing methods. Methods: 3D printing provides the opportunity to rapidly prototype uniquely designed objects from a variety of materials. Common 3D printers are usually limited to printing objects based on thermoplastic materials such as PLA, or ABS. The most commonly available plastic is PLA, which has a density significantly greater than soft tissue. We utilized a popular 3D printer to demonstrate that tissue specific phantom materials can be generated through the careful selection of 3D printing parameters. A series of stepwedges were designed and printed using a Makerbot Replicator2 3D printing system. The print file provides custom adjustment of the infill density, orientation and position of the object on the printer stage, selection of infill patterns, and other control parameters. The x-ray attenuation and uniformity of fabricated phantoms were evaluated and compared to common tissue-equivalent phantom materials, acrylic and BR12. X-ray exposure measurements were made using narrow beam geometry on a clinical mammography unit at 28 kVp on the series of phantoms. The 3D printed phantoms were imaged at 28 kVp to visualize the internal structure and uniformity in different planes of the phantoms. Results: By utilizing specific in-fill density and patterns we are able to produce a phantom closely matching the attenuation characteristics of BR12 at 28 kVp. The in-fill patterns used are heterogeneous, so a judicious selection of fill pattern and the orientation of the fill pattern must be made in order to obtain homogenous attenuation along the intended direction of beam propagation. Conclusions: By careful manipulation of the printing parameters, breast and soft tissue-equivalent phantoms appropriate for use at imaging energies can be fabricated using 3D printing techniques.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

3D localization of electrophysiology catheters from a single x-ray cone-beam projection

Purpose: X-ray images allow the visualization of percutaneous devices such as catheters in real time but inherently lack depth information. The provision of 3D localization of these devices from cone beam x-ray projections would be advantageous for interventions such as electrophysiology (EP), whereby the operator needs to return a device to the same anatomical locations during the procedure. A method to achieve real-time 3D single view localization (SVL) of an object of known geometry from a single x-ray image is presented. SVL exploits the change in the magnification of an object as its distance from the x-ray source is varied. The x-ray projection of an object of interest is compared to a synthetic x-ray projection of a model of said object as its pose is varied. Methods: SVL was tested with a 3 mm spherical marker and an electrophysiology catheter. The effect of x-ray acquisition parameters on SVL was investigated. An independent reference localization method was developed to compare results when imaging a catheter translated via a computer controlled three-axes stage. SVL was also performed on clinical fluoroscopy image sequences. A commercial navigation system was used in some clinical image sequences for comparison. Results: SVL estimates exhibited little change as x-ray acquisition parameters were varied. The reproducibility of catheter position estimates in phantoms denoted by the standard deviations, (σ{sub x}, σ{sub y}, σ{sub z}) = (0.099 mm, 0.093 mm, 2.2 mm), where x and y are parallel to the detector plane and z is the distance from the x-ray source. Position estimates (x, y, z) exhibited a 4% systematic error (underestimation) when compared to the reference method. The authors demonstrated that EP catheters can be tracked in clinical fluoroscopic images. Conclusions: It has been shown that EP catheters can be localized in real time in phantoms and clinical images at fluoroscopic exposure rates. Further work is required to characterize performance in clinical images as well as the sensitivity to clinical image quality.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

MO-E-18C-04: Advanced Computer Simulation and Visualization Tools for Enhanced Understanding of Core Medical Physics Concepts

Purpose: Most medical physics programs emphasize proficiency in routine clinical calculations and QA. The formulaic aspect of these calculations and prescriptive nature of measurement protocols obviate the need to frequently apply basic physical principles, which, therefore, gradually decay away from memory. E.g. few students appreciate the role of electron transport in photon dose, making it difficult to understand key concepts such as dose buildup, electronic disequilibrium effects and Bragg-Gray theory. These conceptual deficiencies manifest when the physicist encounters a new system, requiring knowledge beyond routine activities. Methods: Two interactive computer simulation tools are developed to facilitate deeper learning of physical principles. One is a Monte Carlo code written with a strong educational aspect. The code can “label” regions and interactions to highlight specific aspects of the physics, e.g., certain regions can be designated as “starters” or “crossers,” and any interaction type can be turned on and off. Full 3D tracks with specific portions highlighted further enhance the visualization of radiation transport problems. The second code calculates and displays trajectories of a collection electrons under arbitrary space/time dependent Lorentz force using relativistic kinematics. Results: Using the Monte Carlo code, the student can interactively study photon and electron transport through visualization of dose components, particle tracks, and interaction types. The code can, for instance, be used to study kerma-dose relationship, explore electronic disequilibrium near interfaces, or visualize kernels by using interaction forcing. The electromagnetic simulator enables the student to explore accelerating mechanisms and particle optics in devices such as cyclotrons and linacs. Conclusion: The proposed tools are designed to enhance understanding of abstract concepts by highlighting various aspects of the physics. The simulations serve as virtual experiments that give deeper and long lasting understanding of core principles. The student can then make sound judgements in novel situations encountered beyond routine clinical activities.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

EGS Collab Experiment 1: 3D Seismic Velocity Model and Updated Microseismic Catalog from Double-Difference Seismic Tomography

This package contains a 3D Seismic velocity model and an updated microseismic catalog obtained for a double-difference seismic tomography study. The 3D_seismic_velocity_model text file contains x (m), y(m), z(m), P-wave velocity (km/s), P-wave velocity quality indicator (1 for well-constrained; 0 for poorly constrained), S-wave velocity (km/s), and S-wave velocity quality indicator (1 for well-constrained; 0 for poorly constrained). The Updated_MEQ_catalog text file contains event origin time, x(m), y(m), z(m), error in x (m), error in y (m), error in z (m), and RMS misfit (millisecond). The 3D_seismic_P-wave_velocity_model animation file shows slices of the 3D P-wave velocity model. The 3D_seismic_S-wave_velocity_model animation file shows slices of the 3D S-wave velocity model. The Interactive_MEQ_location_comparison API file is an interactive visualization of the updated microseismic event locations and the original seismic catalog. The visualization allows users to view and compare the event locations by dragging, rotating, and zooming in. An updated version of 3D_seismic_velocity_model and associated animations were included, which were calculated with a more strict assumption for quality indicators.

15 GEOTHERMAL ENERGY↗
DOE OSTI2016

SU-F-T-275: A Correlation Study On 3D Fluence-Based QA and 2D Dose Measurement-Based QA

Purpose: The aim of this paper was to demonstrate the feasibility and creditability of computing and verifying 3D fluencies to assure IMRT and VMAT treatment deliveries, by correlating the passing rates of the 3D fluence-based QA (P(ά)) to the passing rates of 2D dose measurementbased QA (P(Dm)). Methods: 3D volumetric primary fluencies are calculated by forward-projecting the beam apertures and modulated by beam MU values at all gantry angles. We first introduce simulated machine parameter errors (MU, MLC positions, jaw, gantry and collimator) to the plan. Using passing rates of voxel intensity differences (P(Ir)) and 3D gamma analysis (P(γ)), calculated 3D fluencies, calculated 3D delivered dose, and measured 2D planar dose in phantom from the original plan are then compared with those from corresponding plans with errors, respectively. The correlations of these three groups of resultant passing rates, i.e. 3D fluence-based QA (P(ά,Ir) and P(ά,γ)), calculated 3D dose (P(Dc,Ir) and P(Dc,γ)), and 2D dose measurement-based QA (P(Dm,Ir) and P(Dm,γ)), will be investigated. Results: 20 treatment plans with 5 different types of errors were tested. Spearman’s correlations were found between P(ά,Ir) and P(Dc,Ir), and also between P(ά,γ) and P(Dc,γ), with averaged p-value 0.037, 0.065, and averaged correlation coefficient ρ-value 0.942, 0.871 respectively. Using Matrixx QA for IMRT plans, Spearman’s correlations were also obtained between P(ά,Ir) and P(Dm,Ir) and also between P(ά,γ) and P(Dm,γ), with p-value being 0.048, 0.071 and ρ-value being 0.897, 0.779 respectively. Conclusion: The demonstrated correlations improve the creditability of using 3D fluence-based QA for assuring treatment deliveries for IMRT/VMAT plans. Together with advantages of high detection sensitivity and better visualization of machine parameter errors, this study further demonstrates the accuracy and feasibility of 3D fluence based-QA in pre-treatment QA and daily QA. Research reported in this study is supported by the Agency for Healthcare Research and Quality (AHRQ) under award 1R01HS0222888. The senior author received research grants from ViewRay Inc. and Varian Medical System.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-T-41: 3D MTP-TRUS for Prostate Implant

Purpose: Prostate brachytherapy is an effective treatment for early prostate cancer. The current prostate implant is limited to using 2D transrectal ultrassound (TRUS) or machenical motor driven 2D array either in the end or on the side. Real-time 3D images can improve the accuracy of the guidance of prostate implant. The concept of our system is to allow realtime full visualization of the entire prostate with the multiple transverse scan. Methods: The prototype of 3D Multiple-Transverse-Plane Transrectal Ultrasound probe (MTP-TRUS) has been designed by us and manufactured by Blatek inc. It has 7 convex linear arrays and each array has 96 elements. It is connected to cQuest Fire bird research system (Cephasonics inc.) which is a flexible and configurable ultrasound-development platform. The size of cQuest Firebird system is compact and supports the real-time wireless image transferring. A relay based mux board is designed for the cQuest Firebird system to be able to connect 672 elements. Results: The center frequency of probe is 6MHz±10%. The diameter of probe is 3cm and the length is 20cm. The element pitch is 0.205 mm. Array focus is 30mm and spacing 1.6cm. The beam data for each array was measured and met our expectation. The interface board of MTP-TURS is made and able to connect to cQuest Firebird system. The image display interface is still under the development. Our real-time needle tracking algorithm will be implemented too. Conclusion: Our MTP-TRUS system for prostate implant will be able to acquire real-time 3D images of prostate and do the real-time needle segmentation and tracking. The system is compact and have wireless function.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

MolViewSpec: a Mol* extension for describing and sharing molecular visualizations

Data visualization is a pivotal component of a structural biologist’s arsenal. The Mol* Viewer makes molecular visualizations available to broader audiences via most web browsers. While Mol* provides a wide range of functionality, it has a steep learning curve and is only available via a JavaScript interface. To enhance the accessibility and usability of web-based molecular visualization, we introduce MolViewSpec (molstar.org/mol-view-spec), a standardized approach for defining molecular visualizations that decouples the definition of complex molecular scenes from their rendering. Scene definition can include references to commonly used structural, volumetric, and annotation data formats together with a description of how the data should be visualized and paired with optional annotations specifying colors, labels, measurements, and custom 3D geometries. Developed as an open standard, this solution paves the way for broader interoperability and support across different programming languages and molecular viewers, enabling more streamlined, standardized, and reproducible visual molecular analyses. MolViewSpec is freely available as a Mol* extension and a standalone Python package.

Midlik, Adam [European Bioinformatics Institute (U↗
DOE OSTI2019

Effect of helical micro-fins on two-phase flow behavior of R410A evaporating in horizontal round tubes obtained through visualization

This paper presents a new approach in visualization of the evaporation mechanism and the two phase flow. The visualization test section is a transparent micro-fin tube made by 3D printing. The 3D printing technology helps reproduce the real geometry in commercial metal micro-fin tubes. Even though the wall material is different from the real metal, this new method provides a more complete understanding of the mechanisms of flow boiling and the heat transfer enhancement due to micro-fin geometry. To investigate the effect of micro-fin geometries on two-phase flow behavior, R410A flow boiling experiments are conducted at 1°C saturation temperature and visualized through a clear smooth tube and micro-fin tubes of 0°, 10° and 18° helix angles. The results showed that the annular flow pattern in the helical micro-fin tube occurred at a lower vapor quality than the smooth and axial micro-fin tubes. Helix angle affects the transition boundary of stratified wavy flow to wavy annular flow, which shifts downward (to lower mass flux and vapor quality conditions) as the helix angle increases. Other transitions are not significantly affected by the helix angle. Helical micro-fin tubes with different groove directions were made to understand the flow behavior on the upward side and downward side of the tube.

3D printing↗
DOE OSTI2023

A Comparative Study of the Perceptual Sensitivity of Topological Visualizations to Feature Variations

Color maps are a commonly used visualization technique in which data are mapped to optical properties, e.g., color or opacity. Color maps, however, do not explicitly convey structures (e.g., positions and scale of features) within data. Topology-based visualizations reveal and explicitly communicate structures underlying data. Although our understanding of what types of features are captured by topological visualizations is good, our understanding of people's perception of those features is not. Further, this paper evaluates the sensitivity of topology-based isocontour, Reeb graph, and persistence diagram visualizations compared to a reference color map visualization for synthetically generated scalar fields on 2-manifold triangular meshes embedded in 3D. In particular, we built and ran a human-subject study that evaluated the perception of data features characterized by Gaussian signals and measured how effectively each visualization technique portrays variations of data features arising from the position and amplitude variation of a mixture of Gaussians. For positional feature variations, the results showed that only the Reeb graph visualization had high sensitivity. For amplitude feature variations, persistence diagrams and color maps demonstrated the highest sensitivity, whereas isocontours showed only weak sensitivity. These results take an important step toward understanding which topology-based tools are best for various data and task scenarios and their effectiveness in conveying topological variations as compared to conventional color mapping.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Fast and Invertible Simplicial Approximation of Magnetic‐Following Interpolation for Visualizing Fusion Plasma Simulation Data

We introduce a fast and invertible approximation for fusion plasma simulation data represented as 2D planar meshes with connectivities approximating magnetic field lines along the toroidal dimension in deformed 3D toroidal spaces. Scientific variables (e.g., density and temperature) in these fusion data are interpolated following a complex magnetic-field-line-following scheme in the toroidal space represented by a cylindrical coordinate system. This deformation in the 3D space poses challenges for root-finding and interpolation. To this end, we propose a novel paradigm for visualizing and analyzing such data based on a newly developed algorithm for constructing a 3D simplicial mesh within the deformed 3D space. Our algorithm generates a tetrahedral mesh that connects the 2D meshes using tetrahedra while adhering to the constraints on node connectivities imposed by the magnetic field-line scheme. Specifically, we first divide the space into smaller partitions to reduce complexity based on the input geometries and constraints on connectivities. Then, we independently search for a feasible tetrahedralization of each partition, considering nonconvexity. We demonstrate our method with two X-Point Gyrokinetic Code (XGC) simulation datasets on the International Thermonuclear Experimental Reactor (ITER) and Wendelstein 7-X (W7-X), and use an ocean simulation dataset to substantiate broader applicability of our method. An open source implementation of our algorithm is available at https://github.com/rcrcarissa/DeformedSpaceTet.

Ren, Congrong [The Ohio State Univ., Columbus, OH ↗
DOE OSTI2015

3D Band Diagram and Photoexcitation of 2D–3D Semiconductor Heterojunctions

The emergence of a rich variety of two-dimensional (2D) layered semiconductor materials has enabled the creation of atomically thin heterojunction devices. Junctions between atomically thin 2D layers and 3D bulk semiconductors can lead to junctions that are fundamentally electronically different from the covalently bonded conventional semiconductor junctions. In this paper, we propose a new 3D band diagram for the heterojunction formed between n-type monolayer MoS 2 and p-type Si, in which the conduction and valence band-edges of the MoS 2 monolayer are drawn for both stacked and in-plane directions. This new band diagram helps visualize the flow of charge carriers inside the device in a 3D manner. Our detailed wavelength-dependent photocurrent measurements fully support the diagrams and unambiguously show that the band alignment is type I for this 2D-3D heterojunction. Photogenerated electron–hole pairs in the atomically thin monolayer are separated and driven by an external bias and control the “on/off” states of the junction photodetector device. Finally, two photoresponse regimes with fast and slow relaxation are also revealed in time-resolved photocurrent measurements, suggesting the important role played by charge trap states.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Automated Image Segmentation and Processing Pipeline Applied to X–Ray Computed Tomography Studies of Pitting Corrosion in Aluminum Wires

Understanding pitting corrosion is critical, yet its kinetics and morphology remain challenging to study from X-ray computed tomography (XCT) due to manual segmentation barriers. To address this, an automated pipeline leveraging deep learning for efficient large-scale XCT analysis is developed, revealing new corrosion insights. The pipeline enables pit segmentation, 3D reconstruction, statistical characterization, and a topological transformation for visualization. Here, the pipeline is applied to 87 648 XCT images capturing commercial purity aluminum (1100 Al) wire exposed to sodium chloride (NaCl) salt particles over a period of 122 h. The pipeline achieves complete feature extraction and statistical quantification across the entire XCT dataset, leveraging distributed computing environment for high efficiency. Global growth kinetics such as high-level stepwise sigmoidal volume loss patterns and granular individual pit developments are both captured for 36 detected pits. By combining automation, computer vision, and extensive XCT datasets, this research accelerates precise corrosion assessment to enable materials science discoveries at scale.

36 MATERIALS SCIENCE↗
DOE OSTI2023

An innovative and alternative approach toward gear fabrication

In this paper, we present the first demonstration of single-step gear manufacturing via an innovative in-situ friction stir forging approach. This novel process is a natural extension to the friction stir processing technique and relies on shear and normal stresses to form the complex shapes. Friction stir welding pin tool with shoulder is plunged at high revolutions per minute (rpm) into the sample to heat it to the desired temperature and enable plastic flow. Then, the tool is forged at high plunge rate to form the desired structurally-sound and defect free complex shapes. To better visualize the process the experiments are complemented by a 3D thermomechanically coupled, smoothed particle hydrodynamics (SPH) model to understand the material flow pattern both radially and through thickness in the gear teeth, plastic strain distribution, and temperature profile. We have demonstrated application of I-FSF to inherently poor formable AZ31 Mg, AA 7075-T6, and AA5083–10 vol% TiB 2 composite and fabricated 14-tooth spur gears from these materials with minimal farther machining. In conclusion, microstructure of the forged gears exhibited a directional material flow pattern due to the normal forging action and refinement of grains to 6–13 μm through dynamically recrystallization across the radial, through-thickness direction, which is in good agreement with the corresponding SPH simulation results.

42 ENGINEERING↗