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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
DOE OSTI2022

Uniform lithiophilic layers in 3D current collectors enable ultrastable solid electrolyte interphase for high-performance lithium metal batteries

Uniform lithium plating/stripping during charging/discharging in 3D lithiophilic current collectors (3DLCC) is essential to suppress growth of lithium dendrites and to mitigate infinite volume variations of lithium metal for long-lived lithium metal batteries. Additionally, this study reveals the decisive role played by uniformity of the lithiophilic layer of the 3DLCC in achieving uniform lithium plating/stripping. Herein, a series of metal oxide-based 3DLCCs are successfully fabricated with a simple and an ultrafast solution combustion method, from which formation of a uniform and stable lithium dendrite-free solid electrolyte interphase via a uniform lithiophilic layer is demonstrated. Taking Co 3 O 4 as the lithiophilic material deposited on a nickel foam as the 3DLCC (Co@NF) for a proof of concept, the loading amount of Co 3 O 4 , closely correlated with the uniformity of the Co 3 O 4 layer, is modulated to optimize its lithium ion hosting performances. With a uniform Co 3 O 4 layer grown in the 3DLCC, an ultralow nucleation overpotential of 33.4 mV is achieved in half-cell tests at 1 mA cm -2 and 1 mAh cm -2 , and a high Coulombic efficiency of 97.1% is maintained after 210 cycles under a severe cycling condition of 2 mA cm -2 and 1 mAh cm -2 . A small polarization voltage of 13 mV together with an ultralong cycle life of 2400 h at 0.5 mA cm -2 and 1 mAh cm -2 in symmetric Li cells is achieved. Moreover, the composite Li anode delivers sensational rate capability and cyclability in full-cells. This work not only provides new and valuable insights into the interphasial chemistry of solid electrolyte interphase layers, but also sheds light on the development of ultrastable lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2014

Theoretical limit of spatial resolution in diffuse optical tomography using a perturbation model

We have assessed the limit of spatial resolution of timedomain diffuse optical tomography (DOT) based on a perturbation reconstruction model. From the viewpoint of the structure reconstruction accuracy, three different approaches to solving the inverse DOT problem are compared. The first approach involves reconstruction of diffuse tomograms from straight lines, the second – from average curvilinear trajectories of photons and the third – from total banana-shaped distributions of photon trajectories. In order to obtain estimates of resolution, we have derived analytical expressions for the point spread function and modulation transfer function, as well as have performed a numerical experiment on reconstruction of rectangular scattering objects with circular absorbing inhomogeneities. It is shown that in passing from reconstruction from straight lines to reconstruction using distributions of photon trajectories we can improve resolution by almost an order of magnitude and exceed the accuracy of reconstruction of multi-step algorithms used in DOT. (optical tomography)

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

A comparison of digital radiography systems in terms of effective detective quantum efficiency

Purpose: The purpose of this study is to compare digital radiography systems using the metric effective detective quantum efficiency (eDQE), which better reflects digital radiography imaging system performance under clinical operating conditions, in comparison with conventional metrics such as modulation transfer function (MTF), normalized noise power spectra (NNPS), and detective quantum efficiency (DQE). Methods: The eDQE was computed by the calculation of the MTF, the NNPS, the phantom attenuation and scatter, and estimation of x-ray flux. The physical characterization of the systems was obtained with the standard beam conditions RQA5 and RQA9, using the PA Chest phantom proposed by AAPM Report no. 31 simulating the attenuation and scatter characteristics of the adult human thorax. The MTF (eMTF) was measured by using an edge test placed at the frontal surface of the phantom, the NNPS (eNNPS) was calculated from images of the phantom acquired at three different exposure levels covering the operating range of the system (E{sub 0}, which is the exposure at which a system is normally operated, 1/3 E{sub 0}, and 3 E0), and scatter measurements were assessed by using a beam-stop technique. The integral of DQE (IDQE) and eDQE (IeDQE) was calculated over the whole spatial frequency range. Results: The eMTF results demonstrate degradation due to magnification and the presence of scattered radiation. The eNNPS was influenced by the grid presence, and in some systems, it contained structured noise. At typical clinical exposure levels, the magnitude of eDQE(0) with respect to DQE(0) at RQA9 beam conditions was 13%, 17%, 16%, 36%, and 24%, respectively, for Carestream DRX-1, Carestream DRX-1C, Carestream Direct View CR975, Philips Digital Diagnost VM, and GE Revolution XR/d. These results were confirmed by the ratio of IeDQE and IDQE in the same conditions. Conclusions: The authors confirm the robustness and reproducibility of the eDQE method. As expected, the DR systems performed better than the CR systems due to their superior signal-to-noise transfer characteristics. The results of this study suggest the eDQE method may provide an opportunity to more accurately assess the clinical performance of digital radiographic imaging systems by accounting for factors such as the presence of scatter, use of an antiscatter grid, and magnification and focal spot blurring effects, which are not reflected in conventional DQE measures.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Introducing a Phenyl End Group in the Inner Side Chains of A‐DA'D‐A Acceptors Enables High‐Efficiency Organic Solar Cells Processed with Nonhalogenated Solvent

Abstract Power conversion efficiency (PCE) of organic solar cells (OSCs) processed by nonhalogenated solvents is unsatisfactory due to the unfavorable morphology. Herein, two new small molecule acceptors (SMAs) Y6‐Ph and L8‐Ph are synthesized by introducing a phenyl end group in the inner side chains of the SMAs of Y6 and L8‐BO, respectively, for overcoming the excessive aggregation of SMAs in the long‐time film forming processed by nonhalogenated solvents. First, the effect of the film forming time on the aggregation property and photovoltaic performance of Y6, L8‐BO, Y6‐Ph, and L8‐Ph is studied by using the commonly used solvents: chloroform (CF) (rapid film forming process) and chlorobenzene (CB) (slow film forming process). It is found that Y6‐ and L8‐BO‐based OSCs exhibit a dramatic drop in PCE from CF‐ to CB‐processed devices owing to the large phase separation, while the Y6‐Ph and L8‐Ph based OSCs show obviously increased PCEs Furthermore, L8‐Ph‐based OSCs processed by nonhalogenated solvento‐xylene (o‐XY) achieved a high PCE of 18.40% with an FF of 80.11%. The results indicate that introducing a phenyl end group in the inner side chains is an effective strategy to modulate the morphology and improve the photovoltaic performance of the OSCs processed by nonhalogenated solvents.

Chemistry↗
DOE OSTI2026

Development of Advanced, Radiation Resistant, Optical-based Detector Technology for Future Experiments.

The primary objective of this project has been to advance the design of high-performance electromagnetic (EM) calorimeters for future particle physics experiments, to identify and measure the timing, position and energy of electrons, positrons and gamma rays, particularly in high-luminosity environments with intense radiation and pileup conditions. To meet such challenges, the proposed research has focused on the development of ultra-compact, radiation-hard calorimeter modules, to provide excellent timing, spatial, and energy resolution. The work aligns with the DOE’s Basic Research Needs (BRN) for High Energy Physics (HEP) Instrumentation and the research team contributes actively to the Coordinating Panel on Advanced Detectors (CPAD) RDC9 calorimetry collaboration in the USA and the European Committee on Future Accelerators (ECFA) DRD-CALO calorimetry collaboration at CERN, the European Laboratory for Particle Physics located in Geneva, Switzerland. The research builds on the RADiCAL (radiation-hard, ultra-compact) modular sampling calorimeter approach, developed by the research team, which employs dense and very bright optical materials such as LYSO:Ce scintillator plates that are interleaved with very dense tungsten plates to minimize detector size while optimizing performance. The modules are comparable in size to a human index finger, dimensionally 14 mm x 14 mm in cross section and 135 mm in length. And despite the small size, the structure is capable of providing excellent timing and energy resolution. This is facilitated through the use of specialized quartz capillaries filled with wavelength-shifting filaments, positioned at various depths along the length of a module, to collect and guide light signals to silicon photomultipliers (SiPMs) which detect and convert the optical signals to electronic signals for analysis. The primary goals of this project have been: (1) Achieve a timing resolution to σ t ≤ 30 ps for high-energy electrons and photons, important for their association with specific events produced in colliding-beam experiments and for the detection of decays-in-flight of long-lived particles. The project has achieved this goal in beam tests of a single RADiCAL module at CERN, during which a timing resolution of σ t = 27 ps was measured for electrons of energy E = 150 GeV. Based upon a mathematical fit to the data measured over a broad energy range from low energy to high energy, a resolution of σ t ≤ 18 ps has been estimated for electrons of very high (TeV) energy. From these measurements and with further expected technical improvements, the timing resolution should reach σ t ≤ 10 ps, important for searches for discovery physics in upcoming and future experiments. (2) Achieve an energy resolution of σ E / E ≤ 10% / $\sqrt{E}$. The project has yet to achieve this goal, but is close to it, having measured a value of σ E / E ≤ 15.9% / $\sqrt{E}$ using a modular array. Ultimately, the resolution goal is expected to be reached by adjustments to material thicknesses within the modules, which will improve the sampling fraction to measure more precisely the shower energy for lower energy particles. The versatility of the modular RADiCAL approach enables the testing of advanced materials, photosensors and electronics, developed in collaboration with CPAD RDC and ECFA DRD-CALO groups. The structure can distinguish electrons, positrons and gamma rays from hadrons and muons and beam-induced backgrounds, making it a valuable tool in a variety of detector environments, including future circular colliders (FCC-ee, FCC-hh) proposed for the European Laboratory for Particle Physics (CERN), the muon-collider proposed for Fermi National Accelerator Laboratory (Fermilab), and searches for new physics in beam-dump, fixed target and forward-physics experiments. And, while designed with particle physics applications in mind, the technologies developed in this project have the potential for application more broadly in particle and nuclear physics, materials science, and medical physics, underscoring the far-reaching potential of this line of instrumentation research and development.

47 OTHER INSTRUMENTATION↗
DOE OSTI2012

Critical Appraisal of Acuros XB and Anisotropic Analytic Algorithm Dose Calculation in Advanced Non-Small-Cell Lung Cancer Treatments

Purpose: To assess the clinical impact of the Acuros XB algorithm (implemented in the Varian Eclipse treatment-planning system) in non-small-cell lung cancer (NSCLC) cases. Methods and Materials: A CT dataset of 10 patients presenting with advanced NSCLC was selected and contoured for planning target volume, lungs, heart, and spinal cord. Plans were created for 6-MV and 15-MV beams using three-dimensional conformal therapy, intensity-modulated therapy, and volumetric modulated arc therapy with RapidArc. Calculations were performed with Acuros XB and the Anisotropic Analytical Algorithm. To distinguish between differences coming from the different heterogeneity management and those coming from the algorithm and its implementation, all the plans were recalculated assigning Hounsfield Unit (HU) = 0 (Water) to the CT dataset. Results: Differences in dose distributions between the two algorithms calculated in Water were <0.5%. This suggests that the differences in the real CT dataset can be ascribed mainly to the different heterogeneity management, which is proven to be more accurate in the Acuros XB calculations. The planning target dose difference was stratified between the target in soft tissue, where the mean dose was found to be lower for Acuros XB, with a range of 0.4% {+-} 0.6% (intensity-modulated therapy, 6 MV) to 1.7% {+-} 0.2% (three-dimensional conformal therapy, 6 MV), and the target in lung tissue, where the mean dose was higher for 6 MV (from 0.2% {+-} 0.2% to 1.2% {+-} 0.5%) and lower for 15 MV (from 0.5% {+-} 0.5% to 2.0% {+-} 0.9%). Mean doses to organs at risk presented differences up to 3% of the mean structure dose in the worst case. No particular or systematic differences were found related to the various modalities. Calculation time ratios between calculation time for Acuros XB and the Anisotropic Analytical Algorithm were 7 for three-dimensional conformal therapy, 5 for intensity-modulated therapy, and 0.2 for volumetric modulated arc therapy with RapidArc. Conclusion: The availability of Acuros XB could improve patient dose estimation, increasing the data consistency of clinical trials.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Thermal Optimization and Experimental Demonstration of a Silicon Carbide, Half-Bridge Power Module

This paper describes modeling and experimental work to design and demonstrate a silicon carbide (SiC), single-side-cooled power module. Two SiC metal-oxide-semiconductor field-effect transistors (MOSFET) were used for each switch position and packaged on a metalized ceramic substrate. Thermal modeling was first conducted to optimize the module packaging to minimize junction-to-fluid thermal resistance and device temperature variations. This procedure identified the optimal device placement and baseplate thickness to maximize thermal performance. A heat exchanger - incorporating impinging jets of water-ethylene glycol - was designed to cool the module's baseplate to minimize thermal resistance and pumping power. The heat exchanger used relatively low fluid velocities (<1.5 m/s) to minimize erosion-corrosion effects and relatively large fluid channel sizes (>=1 mm) to prevent clogging. The power module concept was fabricated, and experiments were conducted to measure its thermal performance. Direct current was used to power the module devices, and junction temperatures were measured via device temperature-sensitive parameters. The experimental results were found to be in good agreement with model predictions (within 2%) and yielded junction-to-fluid thermal resistance values as low as about 15 mm2 K/W at relatively low pumping power values. The results demonstrate the improved performance associated with jet impingement cooling and represent an improvement over existing channel-flow-type cold plates, which can enable improvements to power density and reliability.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Thermal Performance Benchmarking; NREL (National Renewable Energy Laboratory)

This project proposes to seek out the SOA power electronics and motor technologies to thermally benchmark their performance. The benchmarking will focus on the thermal aspects of the system. System metrics including the junction-to-coolant thermal resistance and the parasitic power consumption (i.e., coolant flow rates and pressure drop performance) of the heat exchanger will be measured. The type of heat exchanger (i.e., channel flow, brazed, folded-fin) and any enhancement features (i.e., enhanced surfaces) will be identified and evaluated to understand their effect on performance. Additionally, the thermal resistance/conductivity of the power module’s passive stack and motor’s laminations and copper winding bundles will also be measured. The research conducted will allow insight into the various cooling strategies to understand which heat exchangers are most effective in terms of thermal performance and efficiency. Modeling analysis and fluid-flow visualization may also be carried out to better understand the heat transfer and fluid dynamics of the systems.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2024

Leveraging MARVEL and SPHERE to Demonstrate NEAMS Thermal Hydraulics Codes

The Single Primary Heat Extraction and Removal Emulator (SPHERE) and Microreactor Applications Research Validation and Evaluation (MARVEL) were utilized to demonstrate thermal hydraulics codes of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. A recent long-duration test of a sodium heat pipe conducted at the SPHERE facility was utilized for the validation of the heat pipe code Sockeye. The first 10 hours of operation featured a startup of the heat pipe from room temperature; this portion was modeled with Sockeye and compared to the experimental data. Measurements included several thermocouple measurements across the length of the heat pipe surface. Two of Sockeye’s heat pipe models were applied to experiment, as well as several models of the cooling at the condenser end of the heat pipe. Sockeye results gave a decent match to the experimental data, with notable discrepancy in the condenser section, where experimental data indicated a significant inactive length of the heat pipe. The MARVEL microreactor was modeled through a coupled simulation of System Analysis Module (SAM) and SubChannel Module (SCM). This multiscale coupled simulation was performed as an exercise to demonstrate the compatibility and applicability of these codes for thermal-hydraulic analysis of microreactors. The coupling between the SCM and SAM codes for multiscale modeling of MARVEL, was achieved through a domain overlapping approach. In this example a transient SAM simulation provided boundary conditions to SCM, and SCM provided pressure drop to SAM.

97 - MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Thermal energy storage in concrete utilizing a thermosiphon heat exchanger

The performance of a lab-scale concrete thermal energy storage (TES) module with a 2-kWh thermal capacity is evaluated at temperatures up to 400 °C. The TES module uses conventional normal weight concrete with thermal and mechanical properties that are tailored for use as a solid thermal energy storage media. A thermosiphon heat exchanger is used to provide rapid heat transfer into the concrete module, which is reinforced with a steel pipe outer shell. The charging and discharging cycles are examined to assess the thermal performance of the concrete and thermosiphon. Based on the results of testing, the thermosiphon is able to repeatably charge the concrete module from 300 to 400 °C over a 4-h period. After 2250 total hours of charge and discharge cycles, there was no observed delamination between the concrete and the thermosiphon or the steel jacket reinforcement. Non-destructive measurements of the concrete indicated no significant degradation of the solid storage media. The experimental results are then used to validate a numerical model of the concrete TES module for parametric study. Finally, varying insulation conditions were analyzed using this model to determine practical configurations for regular operation of the proposed concrete TES module.

25 ENERGY STORAGE↗
DOE OSTI2021

A Modular Mechanism for Downhole Weight-on-Bit and Torque Reaction in Small Diameter Boreholes

Drilling systems that use downhole rotation must react torque either through the drill-string or near the motor to achieve effective drilling performance. Problems with drill-string loading such as buckling, friction, and twist become more severe as hole diameter decreases. Therefore, for small holes, reacting torque downhole without interfering with the application of weight-on-bit, is preferred. In this paper, we present a novel mechanism that enables effective and controllable downhole weight on bit transmission and torque reaction. This scalable design achieves its unique performance through four key features: (1) mechanical advantage based on geometry, (2) direction dependent behavior using rolling and sliding contact, (3) modular scalability by combining modules in series, and (4) torque reaction and weight on bit that are proportional to applied axial force. As a result, simple mechanical devices can be used to react large torques while allowing controlled force to be transmitted to the drill bit. We outline our design, provide theoretical predictions of performance, and validate the results using full-scale testing. The experimental results include laboratory studies as well as limited field testing using a percussive hammer. These results demonstrate effective torque reaction, axial force transmission, favorable scaling with multiple modules, and predictable performance that is proportional to applied force.

15 GEOTHERMAL ENERGY↗
DOE OSTI2014

Modulation instability in a zigzag array of nonlinear waveguides with alternating positive and negative refractive indices

The modulation instability is analytically investigated in a zigzag array of tunnel-coupled optical waveguides with alternating refractive indices and Kerr nonlinearity. Particular solutions to a system of coupled nonlinear equations are found. They describe the propagation of electromagnetic waves that are uniform along the waveguide and their instability is studied. It is shown that the coupling coefficient between the waveguides, which are non-nearest neighbours, has a significant effect on the instability of the waves in question. When the coupling coefficient exceeds a certain threshold, the modulation instability disappears regardless of the radiation power. The influence of the ratio of the wave amplitudes in adjacent waveguides to the instability of the particular solutions is studied. Different variants of the nonlinear response in waveguides are considered. The studies performed present a new unusual type of the modulation instability in nonlinear periodic systems. (metamaterials)

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Results from the CBC3 readout ASIC for CMS 2S-modules

The CBC3 is the latest version of the CMS Binary Chip for readout of the outer radial region of the upgraded CMS Tracker at the High Luminosity LHC. This 254-channel, 130 nm CMOS ASIC is designed to be bump-bonded to a substrate to which sensors will be wire-bonded. It will instrument double-layer 2S-modules, containing two overlaid silicon microstrip sensors, aligned with a parallel orientation. On-chip logic identifies Level-1 trigger primitives from high transverse-momentum tracks by selecting correlated clusters in the two sensors. The CBC3 was delivered in late 2016; wafer probing and performance tests have been carried out. Several prototype modules using the CBC3 have been produced and tested in the lab and in different beams. The results show that the CBC3 satisfies CMS requirements and only small corrections are needed for the final version of the chip for production.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Photovoltaics module reliability for the terawatt age

Photovoltaics (PV), or solar electricity generation, has become the cheapest form of energy in many locations worldwide and, combined with energy storage, has the potential to satisfy most of our electricity needs. PV has grown at an annual compounded growth rate of approximately 30% in the last three decades. Solar energy systems will continue their impressive growth in distributed energy, microgrids, and utility scale, as efforts are made for dependable electricity in an age with increasing extreme weather. However, within this remarkable success lies a new challenge. The growth curve, combined with rapid product innovation and scale up, means that the majority of PV systems are new, without the three years of performance data that have been required in the past to estimate product lifetime. PV reliability has to address this challenge. In this review we present a brief summary of PV reliability starting with brief historical synopsis, detailing some of the technological challenges and present a framework required for long lifetime.

14 SOLAR ENERGY↗
DOE OSTI2022

Comparative Investigation of Current-Source Inverters using SiC Discrete Devices and Power Modules

The purpose of this paper is to investigate the impact of the SiC device packages on the commutation performance characteristics of current-source inverters (CSIs). The parasitic components in the CSI current commutation loop between the two-phase legs and output capacitors have a significant impact on the high-frequency performance of the SiC devices. To meet the elevated current requirements of high-power CSIs, it is often necessary to connect multiple discrete devices in parallel which increases the current commutation loop length. The selection of compact high-power SiC MOSFET and Schottky diode modules instead of discrete devices can be highly desirable to reduce the loop inductance and improve the system performance and power density. Two CSI benchtop prototype units, one with SiC discrete devices and the other with power modules, have been designed and tested, and the performances of the two CSIs are compared. The CSI with SiC power modules significantly reduces the inverter volume and lowers the parasitic inductance by 60% and the voltage ripple amplitude by 20% compared to the CSI unit with discrete devices.

42 ENGINEERING↗
DOE OSTI2014

High speed measurements of neutral beam turn-on and impact of beam modulation on measurements of ion density

Modulation of neutral beams on tokamaks is performed routinely, enabling background rejection for active spectroscopic diagnostics, and control of injected power and torque. We find that there exists an anomalous initial transient in the beam neutrals delivered to the tokamak that is not accounted for by the accelerator voltage and power supply current. Measurements of the charge-exchange and beam photoemission on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] at high speed (200 μs) reveal that the energy of the beam neutrals is constant, but the density of beam neutrals displays dramatic variation in the first 2–3 ms following beam turn-on. The impact of this beam density variation on inferred ion densities and impurity transport is presented, with suggested means to correct for the anomalous transient.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Influence of Photovoltaic Shading on Rooftop Heat Transfer, Building Energy Loads, and Photovoltaic Power Output

Photovoltaic (PV) modules on building rooftops provide shade from summer heating, leading to a reduction in cooling load during hot seasons. However, PV shading also reduces passive solar heating during winter months, leading to an increase in the building heating load during cold seasons. In this study, the heat transfer performance of an enclosure formed by adjacent PV modules is analyzed for three locations in the United States, comparing the daily heat flux through rooftops for the case of a PV-shaded rooftop as well as an unshaded roof. Several result metrics are developed as part of this work, including the saved energy load (SEL), or the energy conserved by adding PV-shading to the rooftop, and the additional energy load (AEL), or the supplemental building energy required to replace shaded solar heating. Lastly, this work calculates the utility factor, being the ratio of SEL and PV power output to AEL as a metric of PV effectiveness. SELs are 5.2, 6.2, and 11.7 kWh/m 2 · year for Dayton, Boise, and Phoenix, respectively, while the AELs for the same locations are 1.6, 1.5, and 2.1 kWh/m 2 · year. The utility factors for the same three locations are 61, 71, and 79. In general, locations with hot, non-cloudy summers and clear skies in winter see the largest utility factor. Further, it is shown that PV shading can conserve building energy during the winter months by preventing radiative losses to cold winter skies.

13 HYDRO ENERGY↗