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At least 955 records · Page 53

Annulus wall boundary layer development in a compressor stage, including the effects of tip clearance

The end-wall boundary layer development in a compressor stage, including the inlet guide vane (IGV) passage and the rotor passage, was measured. The measurement upstream of the rotor and inside the IGV passage were carried out with a five-hole probe. The data (blade-to-blade) inside the IGV passage were carried out with a five-hole probe. The data (blade-to-blade) inside the rotor passage were measured using a three-sensor rotating hot-wire below the tip clearance region and "V' configuration probe inside the clearance region. The rotor exit measurements (blade-to-blade) were acquired with a laser Doppler velocimeter. The velocity profiles and the integral properties are presented and interpreted. The boundary layer is comparatively well behaved up to the leading edge of the rotor, beyond which complex interactions result in very unconventional profiles. The momentum thicknesses decrease in the leakage flow region of the rotor. The momentum thicknesses and the limiting streamline angles predicted from a momentum integral technique agree well with the data up to the leading edge of the rotor.

Lakshminarayana, B.↗

Mass flow sensor utilizing a resistance bridge

A mass flow sensor to be mounted within a duct and measures the mass flow of a fluid stream moving through the duct. The sensor is an elongated thin quartz substrate having a plurality of platinum strips extending in a parallel relationship on the strip, with certain of the strips being resistors connected to an excitation voltage. The resistors form the legs of a Wheatstone bridge. The resistors are spaced a sufficient distance inwardly from the leading and trailing edges of the substrate to lie within the velocity recovery region so that the measured flow is the same as the actual upstream flow. The resistor strips extend at least half-way through the fluid stream to include a substantial part of the velocity profile of the stream. Certain of the resistors detect a change in temperature as the fluid stream moves across the substrate to provide an output signal from the Wheatstone bridge which is representative of the fluid flow. A heater is located in the midst of the resistor array to heat the air as it passes over the array.

Fralick, Gustave C.↗

Spatial Registration Assessments for the SNPP and N20 VIIRS Reflective Solar Bands Using Unscheduled Lunar Observations

The Visible Infrared Imaging Radiometer Suite (VIIRS) is a multi-spectral Earth-observing instrument on board the Suomi-NPP (SNPP) and NOAA-20 (N20) spacecraft, with spectral bands ranging in wavelength from 0.41 to 12.2 μm. For the reflective solar bands (RSB), the bands are calibrated on orbit using both solar diffuser (SD) and lunar observations. The lunar observations use near-monthly scheduled spacecraft maneuvers in order to view the Moon within a desired phase angle range. While the primary purpose of the maneuvers is for radiometric calibration, these observations can also be used to characterize the spatial performance of the instrument, including the band-to-band and detector-to-detector registration (BBR/DDR). The Moon can also be observed without spacecraft maneuvers. However, these observations are over a larger phase angle range. While the geometry of these unscheduled observations is more varied, they can still be used to assess the sensor performance. In this work, we will use unscheduled Moon data to analyze the BBR and DDR of the SNPP and N20 VIIRS RSB. For the BBR, we implemented an image cross-correlation approach, which removes the residual oscillations in the trending data when compared to previous methodologies. For the DDR, we developed an edge fitting approach that accounts for the lunar motion across the VIIRS focal plane array on a scan-by-scan basis using lunar and satellite ephemeris data. In our analysis, we find that the BBR and DDR for both VIIRS RSB are stable on orbit.

Band-to-band registration (BBR)↗

Bright Semiconductor Scintillator for High Resolution X-Ray Imaging

We report on a novel approach to produce oxygen-doped zinc telluride (ZnTe:O), a remarkable group II-VI semiconductor scintillator, fabricated in the columnar-structured or polycrystalline forms needed to fulfill the needs of many demanding X-ray and {gamma}-ray imaging applications. ZnTe:O has one of the highest conversion efficiencies among known scintillators, emission around 680 nm (which is ideally suited for CCD sensors), high density of 6.4 g/cm{sup 3}, fast decay time of {approx}1 {micro}s with negligible afterglow, and orders of magnitude higher radiation resistance compared to commonly used scintillators. These properties allow the use of ZnTe:O in numerous applications, including X-ray imaging, nuclear medicine (particularly SPECT), room temperature radioisotope identification, and homeland security. Additionally, ZnTe:O offers distinct advantages for synchrotron-based high resolution imaging due to the absence of atomic absorption edges in the low energy range, which otherwise reduce resolution due to secondary X-ray formations. We have fabricated films of ZnTe:O using a vapor deposition technique that allows large-area structured scintillator fabrication in a time- and cost-efficient manner, and evaluated its performance for small-angle X-ray scattering (SAXS) at an Argonne National Laboratory synchrotron beamline. Details of the fabrication and characterization of the optical, scintillation and imaging properties of the ZnTe:O films are presented in this paper.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Even Higher-Level Synthesis: An Exploration of AI Hardware Accelerators using HLS4ML

With the rise of artificial intelligence, the popularization of deep learning, and a constantly evolving industry, the demand for flexible and efficient tools has never been greater. As algorithms grow more complex, their runtime and energy consumption increase exponentially. Customized hardware accelerators, long used for specific mathematical operations, remain essential for managing modern applications' computational and power demands. Hardware accelerators can speed up complex computations by orders of magnitude, but their manual design and verification processes are often challenging and time-consuming. High-Level Synthesis (HLS) provides a solution by transforming high-level algorithm descriptions, typically written in C++ or SystemC, into synthesizable RTL suitable for hardware implementation. This approach reduces development time for RTL engineers while offering flexibility beyond what traditional handwritten RTL can provide. We extended this capability to the machine-learning domain with the open-source framework hls4ml, which allows neural networks trained in Python frameworks like Tensorflow or PyTorch to be synthesized into efficient hardware representations for the traditional FPGA and ASIC flows. This breakthrough addresses the growing need for reduced design turnaround and easy verification of ML hardware accelerators with low latency and power efficiency constraints. During this tutorial, we will demonstrate how Python complements HLS by simplifying the ML design process, bridging the gap between software and hardware development. Attendees will explore how we translate neural networks modeled in Python into fixed-point C++ models suitable for HLS workflows. We will dive into strategies like Value-Range Analysis and Quantization-Aware Training, which optimize these designs for deployment and evaluate their accuracy, power consumption, and energy efficiency. To exemplify these concepts, experts from Fermilab will share their experiences applying this technology to high-energy physics experiments, where real-time, low-latency processing is critical. Over the years, Fermilab engineers have demonstrated how deep neural networks, optimized for hardware using hls4ml, can meet the stringent requirements of trigger systems at the CERN Large Hadron Collider. These systems rely on rapid decision-making to process immense data volumes while retaining only the most relevant events for further analysis. The application of hls4ml has also been extended to innovative technologies like smart pixel arrays. These smart pixels integrate ML inference capabilities directly into sensor devices, enabling localized data processing at the pixel level. This approach drastically reduces the need to transmit raw data to external processing units, significantly decreasing power consumption and latency. By embedding neural networks within the pixel architecture, the smart pixels can identify and prioritize relevant data in real time, providing a highly efficient solution for edge computing in scenarios such as particle detectors and imaging systems. Fermilab's work highlights the potential of hardware-accelerated ML in scenarios where both speed and power efficiency are mission-critical. Through this tutorial, attendees will gain valuable insights into the challenges and solutions of deploying ML in hardware. Understanding how HLS and hls4ml streamline the development of neural network-based hardware accelerators is fundamental for the industry's future. Participants will learn how these technologies are shaping the future of AI and scientific computing.

Di Guglielmo, Giuseppe [Fermilab]↗

Protein conformational switch discerned via network centrality properties

Network analysis has emerged as a powerful tool for examining structural biology systems. The spatial organization of the components of a biomolecular structure has been rendered as a graph representation and analyses have been performed to deduce the biophysical and mechanistic properties of these components. For proteins, the analysis of protein structure networks (PSNs), especially via network centrality measurements and cluster coefficients, has led to identifying amino acid residues that play key functional roles and classifying amino acid residues in general. Whether these network properties examined in various studies are sensitive to subtle (yet biologically significant) conformational changes remained to be addressed. Here, we focused on four types of network centrality properties (betweenness, closeness, degree, and eigenvector centralities) for conformational changes upon ligand binding of a sensor protein (constitutive androstane receptor) and an allosteric enzyme (ribonucleotide reductase). We found that eigenvector centrality is sensitive and can distinguish salient structural features between protein conformational states while other centrality measures, especially closeness centrality, are less sensitive and rather generic with respect to the structural specificity. We also demonstrated that an ensembleinformed, modified PSN with static edges removed (which we term PSN*) has enhanced sensitivity at discerning structural changes.

59 BASIC BIOLOGICAL SCIENCES↗

A Near Perfect Spin Balance (Measurement in Chaos)

The stringent spin balance requirements arise from the predecessor of SSMIS, the SSMI. The SSMI sensor spinning portion weighed only 85 pounds and contained 7 channels of radiometric data. The Aerospace Corporation recommended to pass on the same requirements from the smaller SSMI to our larger SSMIS (with slight change for increased weight). The SSMIS spinning portion will weigh about 155 pounds and contain 24 channels of radiometeric data. The SSMIS, on orbit, spins a CCW direction at 31.6 RPM its own drive motor. The packaging of this SSMIS is unique, as it combines three sensor into one unit. This combination allows for concurrently reading data in one beam. The unit will have a polar orbit about 500 miles above the earths surface. One of the primary influences for our receipt of the follow-on contract for the next generation sensor, was the ability to package 24 channels of radiometeric data into about the some volume as its predecessor. The data from SSMIS will be used to measure the following: (1) Ocean surface wind speed, (2) Rain over land an ocean, (3) Cloud water over Ocean, (4) Soil moisture, (5) Ice Concentration, (6) Ice age, (7) Ice Edge and snow edge, (8) Water vapor over Ocean, (9) Surface type, (10) Snow water content, (11) Land surface Temperature, (12) Cloud amount over ocean.

Luntz, R. A.↗

Optimization of Second Fault Detection Thresholds to Maximize Mission POS

In order to support manned spaceflight safety requirements, the Space Launch System (SLS) has defined program-level requirements for key systems to ensure successful operation under single fault conditions. To accommodate this with regards to Navigation, the SLS utilizes an internally redundant Inertial Navigation System (INS) with built-in capability to detect, isolate, and recover from first failure conditions and still maintain adherence to performance requirements. The unit utilizes multiple hardware- and software-level techniques to enable detection, isolation, and recovery from these events in terms of its built-in Fault Detection, Isolation, and Recovery (FDIR) algorithms. Successful operation is defined in terms of sufficient navigation accuracy at insertion while operating under worst case single sensor outages (gyroscope and accelerometer faults at launch). In addition to first fault detection and recovery, the SLS program has also levied requirements relating to the capability of the INS to detect a second fault, tracking any unacceptable uncertainty in knowledge of the vehicle's state. This detection functionality is required in order to feed abort analysis and ensure crew safety. Increases in navigation state error and sensor faults can drive the vehicle outside of its operational as-designed environments and outside of its performance envelope causing loss of mission, or worse, loss of crew. The criteria for operation under second faults allows for a larger set of achievable missions in terms of potential fault conditions, due to the INS operating at the edge of its capability. As this performance is defined and controlled at the vehicle level, it allows for the use of system level margins to increase probability of mission success on the operational edges of the design space. Due to the implications of the vehicle response to abort conditions (such as a potentially failed INS), it is important to consider a wide range of failure scenarios in terms of both magnitude and time. As such, the Navigation team is taking advantage of the INS's capability to schedule and change fault detection thresholds in flight. These values are optimized along a nominal trajectory in order to maximize probability of mission success, and reducing the probability of false positives (defined as when the INS would report a second fault condition resulting in loss of mission, but the vehicle would still meet insertion requirements within system-level margins). This paper will describe an optimization approach using Genetic Algorithms to tune the threshold parameters to maximize vehicle resilience to second fault events as a function of potential fault magnitude and time of fault over an ascent mission profile. The analysis approach, and performance assessment of the results will be presented to demonstrate the applicability of this process to second fault detection to maximize mission probability of success.

Anzalone, Evan↗

The Photoactive Excited State of the B 12 -Based Photoreceptor CarH

In this study we have used transient absorption spectroscopy in the UV–visible and X-ray regions to characterize the excited state of CarH, a protein photoreceptor that uses a form of B 12 , adenosylcobalamin (AdoCbl), to sense light. With visible excitation, a nanosecond-lifetime photoactive excited state is formed with unit quantum yield. The time-resolved X-ray absorption near edge structure difference spectrum of this state demonstrates that the excited state of AdoCbl in CarH undergoes only modest structural expansion around the central cobalt, a behavior similar to that observed for methylcobalamin rather than for AdoCbl free in solution. We propose a new mechanism for CarH photoreactivity involving formation of a triplet excited state. This allows the sensor to operate with high quantum efficiency and without formation of potentially dangerous side products. By stabilizing the excited electronic state, CarH controls reactivity of AdoCbl and enables slow reactions that yield nonreactive products and bypass bond homolysis and reactive radical species formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Fabrication of faceted nanopores in magnesium

In this paper, using high resolution transmission electron microscopy, we showed the fabrication of faceted nanopores with various shapes in magnesium by focused electron beam (e-beam). The characteristics of nanopore shapes and the crystallographic planes corresponding to the edges of the nanopores were discussed in detail. Interestingly, by manipulating the e-beam (e.g., irradiation direction and duration), the nanopore shape and size could be effectively controlled along different directions. Our results provide important insight into the nanopore patterning in metallic materials and are of fundamental importance concerning the relevant applications, such as nanopore-based sensor, etc.

36 MATERIALS SCIENCE↗

Mean velocity and decay characteristics of the near- and far-wake of a compressor rotor blade of moderate loading

This paper reports the experimental study of the three-dimensional characteristics of the mean velocity in the wake of a moderately loaded compressor rotor blade. The measurements were taken with a three-sensor hot-wire probe rotating with the rotor. The wake was surveyed at several radial and axial stations. The loading was found to have substantial effect and this was reflected not only in the axial and tangential components, but also in the radial component. The radial velocities were found to be high very near the trailing-edge and this exhibits the characteristics prevalent in a trailing vortex system. The static pressures across the wake were measured using a direction insensitive spherical head static-stagnation pressure probe. The static pressure was found to be higher inside the wake. These and other measurements are reported and correlated in this paper.

Ravindranath, A.↗

Toxicity evaluation of ZnO nanostructures on L929 fibroblast cell line using MTS assay

ZnO has wide applications in medical and dentistry apart from being used as optoelectronic devices such as solar cells, photodetectors, sensors and light emitting diodes (LEDs). Therefore, the toxicity evaluation is important to know the toxicity level on normal cell line. The toxicity of two grades ZnO nanostructures, ZnO-4 and ZnO-8 have been carried out using cytotoxicity test of MTS assay on L929 rat fibroblast cell line. Prior to that, ZnO-4 and ZnO-8 were characterized for its morphology, structure and optical properties using FESEM, X-ray diffraction, and Photoluminescence respectively. The two groups revealed difference in morphology and exhibit slightly shifted of near band edge emission of Photoluminescence other than having a similar calculated crystallite size of nanostructures. The viability of cells after 72h were obtained and the statistical significance value was calculated using SPSS v20. The p value is more than 0.05 between untreated and treated cell with ZnO. This insignificant value of p>0.05 can be summarized as a non-toxic level of ZnO-4 and ZnO-8 on the L929 cell line.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

A Self-Sustained CPS Design for Reliable Wildfire Monitoring

Continuous monitoring of areas nearby the electric grid is critical for preventing and early detection of devastating wildfires. Existing wildfire monitoring systems are intermittent and oblivious to local ambient risk factors, resulting in poor wildfire awareness. Ambient sensor suites deployed near the gridlines can increase the monitoring granularity and detection accuracy. However, these sensors must address two challenging and competing objectives at the same time. First, they must remain powered for years without manual maintenance due to their remote locations. Second, they must provide and transmit reliable information if and when a wildfire starts. The first objective requires aggressive energy savings and ambient energy harvesting, while the second requires continuous operation of a range of sensors. To the best of our knowledge, this paper presents the first self-sustained cyber-physical system that dynamically co-optimizes the wildfire detection accuracy and active time of sensors. The proposed approach employs reinforcement learning to train a policy that controls the sensor operations as a function of the environment (i.e., current sensor readings), harvested energy, and battery level. Here, the proposed cyber-physical system is evaluated extensively using real-life temperature, wind, and solar energy harvesting datasets and an open-source wildfire simulator. In long-term (5 years) evaluations, the proposed framework achieves 89% uptime, which is 46% higher than a carefully tuned heuristic approach. At the same time, it averages a 2-minute initial response time, which is at least 2.5× faster than the same heuristic approach. Furthermore, the policy network consumes 0.6 mJ per day on the TI CC2652R microcontroller using TensorFlow Lite for Micro, which is negligible compared to the daily sensor suite energy consumption.

54 ENVIRONMENTAL SCIENCES↗

Low-phase-noise surface-acoustic-wave oscillator using an edge mode of a phononic band gap

Low-phase-noise microwave-frequency integrated oscillators provide compact solutions for various applications in signal processing, communications, and sensing. Surface acoustic waves (SAWs), featuring orders-of-magnitude shorter wavelength than electromagnetic waves at the same frequency, enable integrated microwave-frequency systems with much smaller footprint on chip. SAW devices also allow higher-quality (Q) factors than electronic components at room temperature. Here, we demonstrate a low-phase-noise gigahertz-frequency SAW oscillator on 128°Y-cut lithium niobate, where the SAW resonator occupies a footprint of 0.05 mm 2 . Leveraging phononic crystal band-gap-edge modes to balance between Q factors and insertion losses, our 1-GHz SAW oscillator features a low phase noise of -132.5 dBc/Hz at a 10-kHz offset frequency and an overlapping Hadamard deviation of 6.5 × 10 -10 at an analysis time of 64 ms. The SAW resonator-based oscillator holds high potential in developing low-noise sensors and acousto-optic integrated circuits.

42 ENGINEERING↗

Final Progress Report: Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes Feasibility Study

This is the final report of the project titled, 'Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes,' PMIS project number LA10-HUMANID-PD03. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). It summarizes work performed over the FY10 time period. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). Human analysts begin analyzing a spectrum based on features in the spectrum - lines and shapes that are present in a given spectrum. The proposed work was to carry out a feasibility study that will pick out all gamma ray peaks and other features such as Compton edges, bremsstrahlung, presence/absence of shielding and presence of neutrons and escape peaks. Ultimately success of this feasibility study will allow us to collectively explain identified features and form a realistic scenario that produced a given spectrum in the future. We wanted to develop and demonstrate machine learning algorithms that will qualitatively enhance the automated identification capabilities of portable radiological sensors that are currently being used in the field.

07 ISOTOPE AND RADIATION SOURCES↗

Monitoring Ultrafast Spin Crossover Intermediates in an Iron(II) Complex by Broad Band Stimulated X-ray Raman Spectroscopy

Here, the photoinduced spin crossover dynamics of transition metal complexes is of fundamental scientific importance and is used for sensor device applications and solar energy harvesting. Current X-ray and optical spectroscopy experiments for [Fe II (bpy) 3 ], an archetypal earth-abundant metal complex, show conflicting spin dynamics. We have simulated the broad band transient X-ray absorption and hybrid (broad + narrow band) X-ray stimulated Raman signals at the N and Fe K-edges of the key excited state intermediates involved in the spin crossover process of this complex. We find that these signals are much more sensitive to electron and spin populations than transition absorption and may be useful in the design of photovoltaic and artificial photosynthetic systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DriveSense: A Noise-Resilient Framework for Driving Mode Identification

Accurate drive mode classification is essential for enhancing the reliability and predictive maintenance of heavy-duty electric trucks. This study proposes a novel fuzzy logic-based framework, DriveSense, for real-time drive mode classification, addressing key challenges such as sensor noise, transitional behaviors, and computational efficiency. The proposed approach integrates a two-stage filtering pipeline, combining adaptive outlier removal and a dynamic Kalman filter to enhance data quality. A fuzzy inference system with smoothened trapezoidal membership functions is then applied to classify driving modes into standstill, constant speed, acceleration, and deceleration while mitigating the effects of noise and edge cases. Performance evaluation using real-world and simulated drive cycles demonstrates significant improvements in classification accuracy (up to 97.8%), F1-score (up to 0.97), and robustness against noise, while reducing false positives. Comparative analysis against baseline models, demonstrates DriveSense’s superior accuracy and generalizability across diverse driving patterns. The framework’s lightweight and interpretable fuzzy inference engine operates with low computational latency, ensuring compatibility with real-time embedded systems typical of heavy-duty electric trucks. Moreover, DriveSense models transitional behaviors through overlapping fuzzy sets and adaptive borderline classification logic, enabling smooth identification of subtle shifts such as rolling stops or gradual deceleration. These results highlight DriveSense’s potential to enhance predictive maintenance strategies, reduce downtime, and support scalable, fleet-wide diagnostics.

Kumar, Praveen [Oak Ridge National Laboratory (ORN↗

Large-Scale Trajectory Analysis via Feature Vectors

The explosion of both sensors and GPS-enabled devices has resulted in position/time data being the next big frontier for data analytics. However, many of the problems associated with large numbers of trajectories do not necessarily have an analog with many of the historic big-data applications such as text and image analysis. Modern trajectory analytics exploits much of the cutting-edge research in machine-learning, statistics, computational geometry and other disciplines. We will show that for doing trajectory analytics at scale, it is necessary to fundamentally change the way the information is represented through a feature-vector approach. We then demonstrate the ability to solve large trajectory analytics problems using this representation.

58 GEOSCIENCES↗