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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Universal, computer facilitated, steady state oscillator, closed loop analysis theory and some applications to precision oscillators

The theory of oscillator analysis in the immittance domain should be read in conjunction with the additional theory presented here. The combined theory enables the computer simulation of the steady state oscillator. The simulation makes the calculation of the oscillator total steady state performance practical, including noise at all oscillator locations. Some specific precision oscillators are analyzed.

Benjamin Parzen↗
NASA NTRS2012

How to Calibrate Edge Sensors on Segmented Mirror Telescopes

The next generation of large ground based telescopes use segmented mirrors. Sensors mounted on the edge of the segments measure the relative heights of the segments. The segments are actively controlled in height by three actuators per segment, but lateral motion is only passively constrained. Thus there will be some small change in the gap and shear between segments as changing telescope orientation and temperature make small distortions in the telescope structure. These "in-plane" motions place an additional performance burden on the edge sensors, and on the precision with which they must be mounted relative to the optical surface. In addition, both the scaling and offset of sensor edge height readings also vary with changes in gap.

segmented mirrors↗
DOE OSTI2013

Global-View Coefficients: A Data Management Solution for Parallel Quantum Monte Carlo Applications

Quantum Monte Carlo (QMC) applications perform simulation with respect to an initial state of the quantum mechanical system, which is often captured by using a cubic B-spline basis. This representation is stored as a read-only table of coefficients, and accesses to the table are generated at random as part of the Monte Carlo simulation. Current QMC applications, such as QWalk and QMCPACK, replicate this table at every process or node, which limits scalability because increasing the number of processors does not enable larger systems to be run. We present a partitioned global address space (PGAS) approach to transparently managing this data using Global Arrays in a manner that allows the memory of multiple nodes to be aggregated. We develop an automated data management system that significantly reduces communication overheads, enabling new capabilities for QMC codes. Experimental results with QWalk and QMCPACK demonstrate the effectiveness of the data management system.

Niu, Qingpeng↗
DOE OSTI2026

In-Situ Magnetic Field Reconstruction in the MAGIS-100 Experiment

Long-baseline atom interferometers such as the Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100) require stringent control and continuous characterization of background magnetic fields and spatial gradients to prevent systemic phase shifts that mimic ultralight dark matter or gravitational wave signatures. Because direct sensor placement within the ultra-high vacuum beam pipe is infeasible, in-situ magnetic field monitoring relies on external sensor arrays situated in the surrounding annular region. This work demonstrates a field reconstruction framework for a 5.3-meter MAGIS-100 modular section using finite-element Opera simulations. Transverse magnetic fields are expanded using a cylindrical multipole framework as informed by Fermilab’s Muon g-2 experiment, with magnetometer array configurations optimized via Fisher information matrix D-optimality. Inverting external sensor readings through a Gauss-Newton scheme recovers interior tube fields across distinct axial positions. In the discontinuity-averse uniform region (slice pair P4), the model achieves sub-noise-floor performance with a cross-validated root-mean-square error (RMSE) of $6.7227 \times 10^{-4}\text{ A/m}$ ($0.845\times$ sensor noise floor) and an interior field coefficient of variation of $1.71\%$. An elbow criterion in the Fisher bounds establishes $n_{\text{max}} = 2$ as the optimal multipole truncation order to prevent noise amplification from over-parameterization, with $n_{\text{max}} = 3$ (sextupole) order chosen for analysis to demonstrate further complexity and cross-pair comparison. Furthermore, analytical differentiation of the fitted multipole coefficients yields dense spatial maps of the transverse Jacobian gradient matrix $\nabla \mathbf{H}$ along with propagated $1\sigma$ uncertainty bounds across the beam region ($r \le 2.75\text{ in}$). This operational framework confirms that external magnetometer arrays can reliably monitor magnetic field uniformity and spatial gradients along the 100-meter flight path given appropriate sampling for any complexity order.

Appleby, Darwin [William Rainey Harper Coll.; Ferm↗
DOE OSTI2019

Project: Advanced Oxy-Combustion Technology Development and Scale Up for New and Existing Coal-Fired Power Plants (Phase II) (Final Report)

The objective of this project was to develop an advanced Oxy-Combustion Pressurized Fluidized Bed Combustor (Oxy-PFBC) technology and mature it to TRL 6 through pilot testing. Performance goals included demonstrating capture of 90% or greater of the produced carbon dioxide, with no more than a 35% increase in the cost of electricity. A 1 MWth pilot scale plant was designed, built and operated at CanmetENERGY in Ottawa. Extensive support work was carried out on component testing, analysis and commercial planning. The team members included GTI, Linde, Natural Resources Canada (CanmetENERGY), Pennsylvania State University, Electric Power Research Institute (EPRI), and General Electric. Additional research was provided by the University of Ottawa. Funding was provided by the US Department of Energy, Alberta Innovates and each of the team members. The total funding for Phase II was $\$$18.537M with $\$$12.058M. The period of performance for Phase II was from July 1, 2014 through December 31, 2018. Component testing conducted in preparation for pilot testing included cold flow testing at atmospheric and pressurized conditions, and coal and limestone reactivity tests at elevated temperatures and pressures. These tests validated in-bed heat exchanger heat transfer capability, bed stability, and coal particle residence time predictions. They also quantified coal and limestone reactivity at the expected combustor temperatures and pressures. The 1 MWth pilot testing achieved all performance goals with the exception of carbon conversion. The combustor achieved oxy-combustion at the full target pressure of 8 bar. Two key combustor performance goals that were achieved include exceeding the target sulfur capture in the combustor as well as exceeding the acid dewpoint target at full operating pressure. This validates assumptions about the pressures that can be achieved without acid gas condensation and the associated corrosion risks. The ability to achieve target operating pressures supports combustor cost assumptions. In addition, the CO 2 processing unit (CPU), demonstrated a new technology, the deoxidation (DeOxo) reactor. The CPU achieved all of its performance targets, while the DeOxo reactor demonstrated the ability to achieve 100 ppm or less of oxygen in the flue gas stream to meet CO 2 pipeline specs. The pilot combustor was damaged during testing and an incident investigation was conducted. The primary cause of the hardware damage was due to anomalous temperature readings, caused by sensors buried and insulated in bed particles trapped by heat exchanger tubes near the wall. This led to higher gas velocities than intended, which then caused lower fuel residence time, lower carbon conversion, freeboard burning, and undetected excess temperatures in the combustor. As a result, the TRL 6 goal was not achieved. Updated technoeconomic analysis predicts that the Oxy-PFBC can achieve the goal of <35% increase in COE with 90% CO 2 capture if the carbon conversion performance target can be demonstrated in future testing.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS2004

An Efficient End-To-End Model for the Kepler Photometer

The Kepler Mission is designed to characterize the frequency of Earth-sized planets in the habitable zones of solar-like stars in the solar galactic neighborhood by observing >100,000 main-sequence stars in a >100 square degree field of view (FOV) and seeking evidence of transiting planets. As part of the system engineering effort, we have developed an End-To-End Model (ETEM) of the photometer to better characterize the expected performance of the instrument and to guide us in making design trades. This model incorporates engineering information such as the point spread function, time histories of pointing offsets, operating temperature, quantization noise, the effects of shutterless readout, and read noise. Astrophysical parameters, such as a realistic distribution of stars vs. magnitude for the chosen FOV, zodiacal light, and cosmic ray events are also included. For a given set of design and operating parameters, ETEM generates pixel time series for all pixels of interest for a single CCD channel of the photometer. These time series are then processed to form light curves for the target stars and the impact of various noise sources on the combined differential photometric precision can be determined. This model is of particular value when investigating the effects of noise sources that cannot be easily subjected to direct analysis, such as residual pointing offsets, thermal drift or cosmic ray effects. This version of ETEM features extremely efficient computation times relative to the previous version while maintaining a high degree of fidelity with respect to the realism of the relevant phenomena.

performance modeling↗
DOE OSTI2015

Radiation Tolerant Electronics and Digital Processing for the Phase-1 Read-out Upgrade of the ATLAS Liquid Argon Calorimeters

The ATLAS Liquid Argon calorimeters are designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudorapidity region |η|<3.2, and for hadronic calorimetry in the region from |η|=1.5 to |η|=4.9. Although the nominal LHC experimental programme is still in progress, an upgrade of the read-out electronics is being launched to cope with luminosities of up to 3x10{sup 34} cm{sup -2}s{sup -1}, which are beyond the original design by a factor of 3. An improved spatial granularity of the trigger primitives is therefore proposed in order to improve the identification performance for trigger signatures, like electrons, photons, tau leptons, jets, total and missing energy, at high background rejection rates. For the upgrade Phase-1 in 2018, new LAr Trigger Digitizer Boards (LTDB) are being designed to receive higher granularity signals, digitize them on detector and send them via fast optical links to a new LAr digital processing system (LDPS). The LDPS applies a digital filtering and identifies significant energy depositions in each trigger channel. The refined trigger primitives are then transmitted to the first level trigger system to extract improved trigger signatures. The read-out of the trigger signals will process 34000 so-called Super Cells at every LHC bunch-crossing at a frequency of 40 MHz. The new LTDB on-detector electronics is designed to be radiation tolerant in order to be operated for the remaining live-time of the ATLAS detector up to a total luminosity of 3000 fb{sup -1}. For the analog-to-digital conversion (12-bit ADC at 40 MSPS), the data serialization and the fast optical link (5.44 Gb/s) custom components have been developed. They have been qualified for the expected radiation environment of a total ionization dose of 1.3 kGy and a hadron fluence of 6 x 10{sup 13} h/cm{sup 2} with energies above 20 MeV. For the digital components like the ADC, cross-sections for single event effects have been determined. This talk will present R and D results from tests of the radiation tolerant components, the fast data processing electronics and prototypes of the LTDB and LDPS boards. First experience from a Demonstrator setup will be reported, in which about 1/10 of the full Super Cell readout will be equipped with prototype versions of the LTDB and LDPS boards. The Demonstrator will be operated in parallel to the regular ATLAS trigger read-out during the upcoming LHC run. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Battery Thermal Characterization

A well-designed thermal management system is critical to the life and performance of electric-drive vehicles (EDVs) hybrids (HEVs), plug-in hybrids (PHEVs), and all-electric vehicles (EVs). Temperature and temperature uniformity both significantly affect the performance, lifespan, and safety of vehicle energy storage devices. NREL conducts thermal management research and development (R&D) to optimize battery performance and extend useful life. A recognized leader in battery thermal analysis and characterization, NREL evaluates electrical and thermal performance of battery cells, modules, and packs, full energy storage systems, and the interaction of these systems with other vehicle components. The lab's performance assessments factor in the design of the thermal management system, the thermal behavior of the cell, battery lifespan, and safety of the energy storage system, as well as full integration into a vehicle. The lithium-ion (Li-ion) batteries found in most of today's electric-drive vehicles are smaller and more lightweight than previous nickel-metal hydride (NiMH) technology, but they are also more sensitive to overheating, overcharging, and extreme spikes in temperature known as thermal runaway. High temperatures diminish battery life and increase battery replacement costs, while low temperatures decrease battery power and capacity, all of which impact vehicle range, performance, and affordability. NREL's breakthrough research is focused on reducing thermal barriers to achieve more uniform temperatures. NREL uses its R&D 100 Award-winning Isothermal Battery Calorimeters, the only instruments in the world capable of such precise thermal measurements, for much of this research. Calorimeter readings are paired with thermal imaging of batteries using infrared cameras to evaluate battery temperature distribution. In addition, NREL is working with industry to develop computer-aided engineering software tools to optimize thermal management of batteries. NREL's analysis for the U.S. Advanced Battery Consortium (USABC) show that optimized thermal management can increase battery power by more than 10%. Without proper thermal management, an EDV battery can last more than 10 years in a temperate climate, like in Minnesota, but only 7 years in a hot climate, such as in Arizona. In extreme instances, battery overheating can pose safety hazards, including fires. Performance: Maintaining desired temperature ranges is critical in optimizing EDV battery storage capacity, lifespan, and performance, and eventually impacts cost and consumer acceptance. NREL's breakthrough research focuses on achieving more uniform temperatures while a vehicle is in motion and actively generating heat, as well as when it is parked and exposed to ambient temperatures over prolonged periods of time. Safety: Most energy storage systems deliver maximum performance at higher temperatures. However, this extreme heat can overload systems and create dangerous conditions. NREL evaluation helps to more effectively regulate thermal characteristics, providing greater safeguards and stronger performance. NREL has invented a device that emulates internal short circuits in batteries to better understand how to prevent future failures and related hazards.

25 ENERGY STORAGE↗
DOE OSTI2019

Prevalence and variability in reporting of clinically actionable incidental findings on attenuation-correction CT scans in a veteran population

Background: Myocardial perfusion imaging (MPI) often employs attenuation-correction computed tomography (CTAC) to reduce attenuation artifacts and improve specificity. While there is no specific guideline on how they should be reported, incidental noncardiac findings identified on these scans may be clinically significant. The prevalence of these findings in veterans is not currently known. In addition, variability in reporting these findings may depend on the interpreting physician’s specialty. Methods: To guide future decision-making, CTACs in veterans referred for MPI were prospectively evaluated in a quality-control project for a set of prespecified actionable incidental findings by cardiologists and a radiologist. Results: On the 771 scans performed over eight months, 285 incidental noncardiac findings were identified by the interpreting cardiologists and 378 were identified by the interpreting radiologist. Pulmonary nodules were the most common occurring in 20% of studies read by the radiologist. Interreader agreements between cardiologists and the radiologist were poor for pulmonary nodules ≥ 10 mm and hiatal hernias; fair for pulmonary nodules < 10 mm, extracardiac masses, and aortic aneurysms; and moderate for pleural plaques. Conclusion: Incidental noncardiac findings on CTACs are common in our veteran population. Overall interobserver agreement in identifying these findings between cardiologists and radiologists is fair. Specific guidelines are needed on how CTACs should be read and reported.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Serpent transient analyses of GIACINT geometrical change experiments

This paper simulates seven transient experiments with geometrical movements performed at the GIACINT facility of Belarus. These experiments include three slow control rods insertion in more than 25 s, one fast control rod insertion in less than 1 s, and three water moderator draining transients. In the fast control rod insertion experiment, the control rods are first pushed by a mechanical spring and then let fall by gravity in the assembly. In this experiment, the control rods speed varies because of the initial spring force, the gravitational acceleration, and the water buoyancy force. In all other transient experiments, the geometry change occurs with a constant speed. The Serpent computer program was utilized to simulate these transient experiments with geometrical changes by performing two separate computations. One time-independent computation is performed in criticality mode and the other time-dependent computation is performed in dynamic-source mode. The first computation writes the neutron population and delayed neutron precursors for starting the transient simulation. The second computation divides the transient time into several time bins, reads the two files from the first computation, and updates them at the end of each time bin. The Serpent simulation results obtained for this set of experiments are in good agreement with the time dependent experimental measurements. In addition, Serpent and MCNP simulations results show an excellent agreement for the water moderator transient

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2014

Large scale electromechanical transistor with application in mass sensing

Nanomechanical transistor (NMT) has evolved from the single electron transistor, a device that operates by shuttling electrons with a self-excited central conductor. The unfavoured aspects of the NMT are the complexity of the fabrication process and its signal processing unit, which could potentially be overcome by designing much larger devices. This paper reports a new design of large scale electromechanical transistor (LSEMT), still taking advantage of the principle of shuttling electrons. However, because of the large size, nonlinear electrostatic forces induced by the transistor itself are not sufficient to drive the mechanical member into vibration—an external force has to be used. In this paper, a LSEMT device is modelled, and its new application in mass sensing is postulated using two coupled mechanical cantilevers, with one of them being embedded in the transistor. The sensor is capable of detecting added mass using the eigenstate shifts method by reading the change of electrical current from the transistor, which has much higher sensitivity than conventional eigenfrequency shift approach used in classical cantilever based mass sensors. Numerical simulations are conducted to investigate the performance of the mass sensor.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Performance of an X-γ ray detection system based on a thick silicon LGAD

We present the performance of a X-γ ray detection systems based on a 300 µm thick silicon low-gain avalanche diode (LGAD) and of an equivalent Diode structure without the gain layer, read-out by a custom-made low-noise charge amplifier. For the LGAD structure, the multiplication gains M s from 10.2 to 19.3 are measured, and the Equivalent Noise Charge (ENC) components have been studied in detail. As expected, a significant reduction of the white and 1/f voltage series and dielectric ENC components is observed with increasing gain, shortening the optimum peaking time to τ = 0.4÷8 μs depending on the gain value, with respect to the standard diode, while the parallel ENC component increases proportionally to the gain up to M s = 15. Setting the gain M s = 12.7, a minimum ENC = 34.5 electrons r.m.s. (298 eV FWHM) at τ = 1 μs is found. However, the electronic noise, evaluated on the pulser FWHM, is found to only marginally contribute to the width of the spectral lines of a radioactive source, which are dominated instead by the statistical noise of the charge multiplication within the LGAD structure. The spectral lines' excess width is found to be proportional to the signal multiplication gain M s and increases with the energy of the photons. A minimum line width of 850 eV FWHM at 13.9 keV is measured at room temperature, τ = 2 μs and a gain M s = 10.2.

47 OTHER INSTRUMENTATION↗
DOE OSTI2014

SU-E-CAMPUS-J-01: TG142 Complied Comprehensive Commissioning and Quality Assurance Procedure for Respiratory Gating

Purpose: To develop and establish a comprehensive gating commissioning and quality assurance procedure in compliance with TG142. Methods: Quality assurance tests on three Varian LINACs included beam output and energy constancy, calibration of surrogate, as well as phase and amplitude gating temporal accuracy. A diode array (MapCHECK 2) and film (Gafchromic EBT2) were used to measure the temporal accuracy of phase and amplitude gating windows. A motion simulation device (MotionSim) was used to simulate respiratory motion for both detectors. An end-to-end test was also performed on all three machines. The overall accuracy and uncertainty was analyzed and compared. Results: The end-to-end test using an anthropomorphic lung phantom (CIRS) results in an OSL dose difference reading within 5% (within measurement uncertainty) for both phase and amplitude gated treatment. Film results showed < 1% agreement between profiles for gated delivery and predicted dose. The diode array demonstrated an 80% passing rate for gamma criteria of 2%/0.2 mm, which results in a 111 msec temporal accuracy. However, the diode array is limited by its spatial resolution of measurements, due to its 7.07 mm diode spacing. Film provided higher measuring resolution, thus demonstrated a temporal accuracy of <100 msec. Conclusion: Results showed consistent respiratory gating stability and accuracy. MapCHECK 2 may not be sufficient for the temporal accuracy test in the respiratory gating treatment in order to meet the corresponding tolerance in TG142. One would need to decrease respiratory motion speed from the surrogate or tighten the gating window in order to be within tolerance of 100 msec temporal accuracy per TG-142. The end-to-end test offers insight to the overall accuracy and uncertainties with a gated protocol. Compared to static delivery, respiratory motion increases the overall uncertainty of treatment delivery from 3% to 5% dose difference.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

DLLExternalCode

DLLExternalCode is the a general dynamic-link library (DLL) interface for linking GoldSim (www.goldsim.com) with external codes. The overall concept is to use GoldSim as top level modeling software with interfaces to external codes for specific calculations. The DLLExternalCode DLL that performs the linking function is designed to take a list of code inputs from GoldSim, create an input file for the external application, run the external code, and return a list of outputs, read from files created by the external application, back to GoldSim. Instructions for creating the input file, running the external code, and reading the output are contained in an instructions file that is read and interpreted by the DLL.

Smith, Frank↗
DOE OSTI2020

Generating MCNP Input Files for Unstructured Mesh Geometries

Los Alamos National Laboratory's (LANL) Monte Carlo N-Particle (MCNP) transport code version 6 has the capability for tracking particles on unstructured mesh (UM) geometry models. The MCNP UM feature has been developed for performing calculations of complex geometry models. This capability tracks particles on hybrid geometries where finite element meshes are embedded into constructive solid geometry (CSG) cells. The MCNP UM feature was originally designed to read UM models created by Abaqus/CAE software suite. MCNP versions 6.2.0 and later can process UM models read from Abaqus input les or MCNPUM les converted from Abaqus input les. Sandia National Laboratory's Cubit Toolkit and other finite element analysis software packages may generate UM models and then convert these models into Abaqus input formats.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Tensile Performance Sensitivity to Variations of Standard 17-4 PH Heat Treatments on LPBF-Produced Material

Standard heat treatments for metals of a particular composition are typically designed with the assumption of a conventional starting microstructure, such as that produced by casting or wrought processing. When applied to metals fabricated by Laser Powder Bed Fusion (LPBF) metal additive manufacturing (AM), these heat treatments can produce inconsistent performance due to the unique as-built microstructures. This study investigates how modifications to standard heat treatments for 17-4 PH steel influence the microstructure and mechanical properties of LPBF-fabricated material. Specimens were produced and subjected to varying solutionizing and homogenizing treatments followed by standard aging treatments. Microstructures were characterized using optical microscopy, Electron Backscatter Diffraction (EBSD), and X-ray diffraction (XRD), and mechanical properties were evaluated through uniaxial tensile testing. Based on these results, recommendations are provided for achieving improved wrought-like performance in LPBF 17-4 PH steel.

17-4 PH↗
NASA NTRS1972

Effect of operating conditions on the exhaust emissions from a gas turbine combustor

Exhaust concentrations of total unburned hydrocarbons, carbon monoxide, and nitric oxide were measured from a single J-57 combustor liner installed in a 30 diameter test section. Tests were conducted over a range of inlet total pressures from 1 to 20 atmospheres, inlet total temperatures from 310 to 590 K, reference velocities from 8 to m/sec, and fuel-air ratios from 0.004 to 0.015. Most of the data were obtained using ASTM A-1 fuel; however, a limited number of tests was performed with natural gas fuel. Combustion efficiency and emission levels are correlated with operating conditions. Sampling error at operating conditions for which combustion efficiency was below about 90 percent resulted in abnormally low readings for hydrocarbon emissions.

Briehl, D.↗
NASA NTRS1982

Combined discrete network. Continuous control modelling of operator behavior

The situation in which an operator is faced with a continuous control task plus one or more discrete information processing tasks is discussed. A modelling approach which has the capability of realistically representing both types of tasks and the resulting interactions is sought. The modelling approach utilizes discrete network models for the cognitive tasks and elements of an open-loop - closed-loop control representation for the continuous task. the approach is demonstrated through its application to a simulated Digital Avionics Information System in which subjects were required to perform retrieval and processing tasks as well as flight control. This model differs from conventional model in that system status sampling is not necessarily continuous or periodic. Rather, the pilot is assumed to read system status displays only as time permits and operate in a so-called open-loop preprogrammed fashion between sampling.

Miller, R. A.↗