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DOE OSTI2020

Current Density Regulated Atomic to Nanoscale Process on Li Deposition and Solid Electrolyte Interphase Revealed by Cryogenic Transmission Electron Microscopy

Current density has been perceived to play a critical rule for controlling Li deposition morphology and solid electrolyte interphase (SEI). However, the atomic level mechanism of current density on Li deposition and the SEI remains unclear. In this work, based on cryogenic transmission electron microscopy imaging combined with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy electronic structure analyses, we reveal the atomic level correlation of Li deposition morphology and SEI with current density. We discover that increasing current density leads to increased overpotential for Li nucleation and growth, leading to the transition from growth-limited to nucleation-limited mode for Li dendrite. Independence of current density, the electrochemically deposited Li metal (EDLi) exhibits crystalline whisker-like morphology. The SEI formed at low current density (0.1 mA cm -2 ) is monolithic amorphous; while, a current density of above 2 mA cm -2 leads to a mosaic structured SEI, featuring an amorphous matrix with Li 2 O and LiF dispersoids, and the thickness of the SEI increases with the increase of current density. Uniquely, the Li 2 O particles is spatially located at the top surface of the SEI, while LiF is spatially adjacent to the Li-SEI interface. These results highlight the possible tuning of crucial structural and chemical features of EDLi and SEI through altering deposit conditions and consequently direct correlation with electrochemical performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2015

Low-reflection beam refractions by ultrathin Huygens metasurface

We propose a Huygens source unit cell to develop an ultrathin low-reflection metasurface, which could provide extreme controls of phases of the transmitted waves. Both electric and magnetic currents are supported by the proposed unit cell, thus leading to highly efficient and full controls of phases. The coupling between electric and magnetic responses is negligible, which will significantly reduce the difficulty of design. Since the unit cell of metasurface is printed on two bonded boards, the fabrication process is simplified and the thickness of metasurface is reduced. Based on the proposed unit cell, a beam-refracting metasurface with low-reflection is designed and manufactured. Both near-field and far-field characteristics of the beam-refracting metasurface are investigated by simulations and measurements, which indicate that the proposed Huygens metasurface performs well in controlling electromagnetic waves.

36 MATERIALS SCIENCE↗

DOE OSTI2019

How to detect and correct myocardial creep in myocardial perfusion imaging using Rubidium-82 PET?

Reliability of myocardial blood flow (MBF) quantification in myocardial perfusion imaging (MPI) using PET can majorly be affected by the occurrence of myocardial creep when using pharmacologically induced stress. In this paper, we provide instructions on how to detect and correct for myocardial creep. For example, in each time frame of the PET images the myocardium contour and the observed activity have to be compared to check for misalignments. In addition, we provide an overview of the functionality of commonly used software packages to perform this quality control step as not all software packages currently provide this functionality. Furthermore, important clinical considerations to obtain accurate MBF measurements are given.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2018

Re-emerging Infectious Disease (RED) Alert tool

Objective: Although relying on verbal definitions of "re-emergence", descriptions that classify a “re-emergence” event as any significant recurrence of a disease that had previously been under public health control, and subjective interpretations of these events is currently the conventional practice, this has the potential to hinder effective public health responses. Defining re-emergence in this manner offers limited ability for ad hoc analysis of prevention and control measures and facilitates non-reproducible assessments of public health events of potentially high consequence. Re-emerging infectious disease alert (RED Alert) is a decision-support tool designed to address this issue by enhancing situational awareness by providing spatiotemporal context through disease incidence pattern analysis following an event that may represent a local (country-level) re-emergence. The tool’s analytics also provide users with the associated causes (socioeconomic indicators) related to the event, and guide hypothesis-generation regarding the global scenario. Introduction: Definitions of “re-emerging infectious diseases” typically encompass any disease occurrence that was a historic public health threat, declined dramatically, and has since presented itself again as a significant health problem. Examples include antimicrobial resistance leading to resurgence of tuberculosis, or measles re-appearing in previously protected communities. While the language of this verbal definition of “re-emergence” is sensitive enough to capture most epidemiologically relevant resurgences, its qualitative nature obfuscates the ability to quantitatively classify disease re-emergence events as such.

Contextual Awareness↗

DOE OSTI2024

Modular DC circuit breaker with integrated energy storage for future DC networks

A T-breaker is an all-in-one solution for dc microgrid fault protection, power flow control, and power quality improvement. A T-breaker features a modular multilevel “T” structure with integrated energy storage devices. The two horizontal arms of the T-breaker realize fault current breaking, load voltage compensation, and power flow control; and the vertical arm of the T-breaker realizes shunt compensation. The configuration provides excellent voltage scalability and relaxes the requirements on the switching signal synchronization during fault transients. The local energy storage in sub-modules eases the fault energy dissipation requirement placed on the traditionally-adopted surge arrestors. The modular multilevel structure also offers immense control flexibility for all types of targeted functions of the provided T-breaker.

Wang, Jin↗

DOE OSTI2017

Ultrafast imprinting of topologically protected magnetic textures via pulsed electrons

Short electron pulses are demonstrated to trigger and control magnetic excitations, even at low electron current densities. We show that the tangential magnetic field surrounding a picosecond electron pulse can imprint topologically protected magnetic textures such as skyrmions in a sample with a residual Dzyaloshinskii-Moriya spin-orbital coupling. Characteristics of the created excitations such as the topological charge can be steered via the duration and the strength of the electron pulses. Here, the study points to a possible way for a spatiotemporally controlled generation of skyrmionic excitations.

36 MATERIALS SCIENCE↗

DOE OSTI2025

The Crucial Role of Vacancy Concentration in Enabling Superatomic Diffusion in Lithium Intermetallics

Anode-free solid-state Li batteries promise significant increases in energy densities compared to current commercial batteries that rely on liquid electrolytes. Major challenges persist in controlling morphological evolution during the plating and stripping of lithium metal at the anode current collector. Elemental additives that alloy with lithium have been found to modify the plating and stripping behavior of lithium. Many alloying elements form intermetallics with lithium and the mobility of Li through these intermetallics is believed to have an important effect on morphological evolution. This study shows that Li transport coefficients through intermetallics span a wide range in values, with the B32 LiAl intermetallic predicted to have a Li tracer diffusion coefficient as high as 10 –6 cm 2 /s at room temperature, which is 8 orders of magnitude larger than that of isostructural B32 LiZn. This work demonstrates the crucial role of vacancy concentration in controlling the mobility of Li atoms through intermetallics. While the migration barriers for Li-vacancy exchanges in both LiAl and LiZn are remarkably low, the superatomic conductivity in LiAl is shown to arise from the unique electronic structure of the B32 LiAl compound, which favors high concentrations of vacancies.

25 ENERGY STORAGE↗

DOE OSTI2018

System and method of energy management control

A method of controlling energy consumption in a building includes receiving occupancy data including at least one of occupant request data and occupant schedule data, receiving weather data including at least one of current weather measurement data and weather forecast data, generating an output control signal based on the occupancy data and the weather data, and transmitting the output control signal to a building automation system (BAS) of the building. The occupant request data includes a current request, and the occupant schedule data includes a predicted occupant schedule. The output control signal adjusts a building control device in a zone in the building.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2023

Control System of Multi-Port Autonomous Reconfigurable Solar Power Plant (MARS) & HIL Platforms for Design

Multi-port autonomous reconfigurable solar power plant (MARS) provides an attractive alternative to connect photovoltaic (PV) and energy storage systems (ESSs) to high-voltage direct current (HVdc) links and high-voltage alternating current (ac) grids. In this paper, a unique hierarchical control system of MARS is proposed and evaluated. To evaluate the control system and associated algorithms in early-stage research of complex architectures like MARS, it is important to develop unique suitable hardware-in-the-loop (HIL) platforms. In this paper, the HIL platforms for MARS to evaluate the performance of the hierarchical control system and the control algorithms implemented are presented. Further, they help with the design process of control systems. The real-time simulation models and algorithms that are utilized for MARS in the HIL platforms are also discussed in the paper. The HIL experiments of the control system of MARS showcase the capability to provide continuity of operation under faults and frequency support to the power grid during loss of generation. They also showcase the stability of the proposed hierarchical control system of MARS.

14 SOLAR ENERGY↗

DOE OSTI2018

Interarea Oscillation Damping Control Using High-Voltage DC Transmission: A Survey

High-voltage, direct current (HVDC) transmission lines are increasingly being installed in power systems around the world, and this trend is expected to continue with advancements in power electronics technology. These advancements are also bringing multi-terminal direct current (MTDC) systems closer to practical application. In addition, the continued deployment of phasor measurement units (PMUs) makes dynamic information about a large power system readily available for highly controllable components, such as HVDC lines. All these trends have increased the appeal of modulating HVDC lines and MTDC systems to provide grid services in addition to bulk power transfers. This paper provides a literature survey of HVDC and MTDC damping controllers for interarea oscillations in large interconnected power systems. The literature shows a progression from theoretical research to practical applications. There are already practical implementations of HVDC modulation for lines in point-to-point configuration, although the modulation of MTDC systems is still in the research stage. As a conclusion, this paper identifies and summarizes open questions that remain to be tackled by researchers and engineers.

Elizondo, Marcelo A. (ORCID:000000026621252X)↗

DOE OSTI2024

Heliostat Observation System Commercialization Qualification HOS-C-Q (Final Technical Report)

Heliostat fields are one of the main components of a concentrated solar thermal plant. As GEN3 technology has been developed at pilot plant level targeting higher temperatures >700C, having a precise Heliostat field control system will enable the success of the GEN3 technology. Heliogen Inc. has developed the next generation of control systems for heliostat fields. Their early development was on single facet heliostats at their R&D facility in Lancaster, California. This new system allows for a closed loop integration to a current open loop setup of a regular Heliostat control system. Sandia National Laboratories and Heliogen Inc. have partnered together to test Heliogen’ s innovative new SOHOT system at the National Solar Thermal Test Facility.

14 SOLAR ENERGY↗

DOE OSTI2015

Series-nonuniform rational B-spline signal feedback: From chaos to any embedded periodic orbit or target point

The self-controlling feedback control method requires an external periodic oscillator with special design, which is technically challenging. This paper proposes a chaos control method based on time series non-uniform rational B-splines (SNURBS for short) signal feedback. It first builds the chaos phase diagram or chaotic attractor with the sampled chaotic time series and any target orbit can then be explicitly chosen according to the actual demand. Second, we use the discrete timing sequence selected from the specific target orbit to build the corresponding external SNURBS chaos periodic signal, whose difference from the system current output is used as the feedback control signal. Finally, by properly adjusting the feedback weight, we can quickly lead the system to an expected status. We demonstrate both the effectiveness and efficiency of our method by applying it to two classic chaotic systems, i.e., the Van der Pol oscillator and the Lorenz chaotic system. Further, our experimental results show that compared with delayed feedback control, our method takes less time to obtain the target point or periodic orbit (from the starting point) and that its parameters can be fine-tuned more easily.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2014

Radiation Resistance of XLPE Nano-dielectrics for Advanced Reactor Applications

Recently there has been renewed interest in nuclear reactor safety, particularly as commercial reactors are approaching 40 years service and lifetime extensions are considered, as well as for new reactor building projects around the world. The materials that are currently used in cabling for instrumentation, reactor control, and communications include cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), polyvinyl chloride (PVC), neoprene, and chlorosulfonated polyethylene. While these materials show suitable radiation tolerance in laboratory tests, failures before their useful lifetime occur due to the combined environmental effects of radiation, temperature and moisture, or operation under abnormal conditions. In addition, the extended use of commercial reactors beyond their original service life places a greater demand on insulating materials to perform beyond their current ratings in these nuclear environments. Nanocomposite materials that are based on XLPE and other epoxy resins incorporating TiO2, MgO, SiO2, and Al2O3 nanoparticles are being fabricated using a novel in-situ method established at ORNL to demonstrate materials with increased resistance to radiation. As novel nanocomposite dielectric materials are developed, characterization of the non-irradiated and irradiated nanodielectrics will lead to a knowledge base that allow for dielectric materials to be engineered with specific nanoparticle additions for maximum benefit to wide-variety of radiation environments found in nuclear reactors. This paper presents the initial findings on the development of XLPE-based SiO2 nano-composite dielectrics in the context of electrical performance and radiation degradation.

dielectrics↗

DOE OSTI2022

Cyber-Physical Dynamic System (CPDS) Modeling for Frequency Regulation and AGC Services of Distributed Energy Resources

The substantial integration of renewable energy brings significant challenges to balance the system in real time because of the variability and intermittency of renewable power. For the reliable system operation, the frequency regulation service is used to stabilize the system frequency through automatically balancing the system generation and load. On one hand, with the substantially increasing deployment of renewable energy in electricity system, the requirement of frequency regulation (FR) services increases significantly. On the other hand, the current main resource of FR services, the controllable conventional generation, is continuously decreasing in the system generation mix. This means that in the future high renewable penetration power system, additional and alternative reliable FR services providers such as distributed energy storage (DES) resources should be explored. Although the capability of utility-scale energy storage to provide FR services has been demonstrated, the integrated control and dynamic modeling of distributed energy resource (DER) providing frequency regulation grid services has been rarely explored. There are several challenges to adopt DERs to provide reliable grid services as illustrated in FERC 755. First, the distributed installation of DES requires a comprehensive cyber-physical dynamic system (CPDS) modeling to fully consider the impacts of the communication latency variability on its real time FR provision capability. Unlike the conventional generators, there are two-layer communication between DERs and system operators which increase the communication delay. Second, unlike the conventional generators whose dynamic models have been comprehensively studied, the difference among individual DER components' power-dynamic characteristic brings challenges in the accurate dynamic AGC modeling of its power-frequency relationship. Third, the temporal dependent state of charge uncertainty of DERs challenges DERs' power and frequency regulation capacities scheduling in the look-ahead generation scheduling. Therefore, the aggregator should optimize the frequency regulation provision from individual DER in real time. To overcome these challenges, this project proposes a cyber-physical dynamic system (CPDS) model to handle the uncertainty of DERs two-layer communication latency and power dynamics. The variability of DERs' communication delay and dynamic constraints will be comprehensively modeled. The DERs' AGC model with communication delay is designed to validate DESs' frequency regulation services. Like current performance-based frequency regulation evaluation, the delivery of DERs' frequency regulation will be assessed through post-analysis of the actual AGC response with respect to the AGC control signal from system operators. Consequently, the reliability improvement with DERs providing reliable frequency regulation services can be evaluated from a comprehensive perspective considering all the dynamics of communication and power.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2025

A Novel Three-Phase Isolated LLC and Non-Isolated LCL-T Resonant Converter for Fuel Cell Applications

In this paper, a novel three-phase isolated LLC and non-isolated LCL−T resonant converter topologies are introduced for fuel cell applications. In order to improve the fuel cell DC/DC converter efficiency, the current amplitude should be reduced in the power stage components. Cascaded connections of fuel cell blocks through a controllable system enable using higher voltage amplitude and bring the current amplitude lower at the target power. In this way, power losses in the passive components can be reduced, and maximum energy transfer can be established, improving the DC/DC converter efficiency from the fuel cell to the load. The introduced new converter also achieves soft switching (ZVS), minimizing the switching losses in all input and output load conditions. The presented three-phase isolated LLC and non-isolated LCL−T resonant converter systems, fed by three fuel cell modules with an output range of 190380 V, deliver 580−730 V at 450 kW maximum output power. The results reveal that the proposed systems have the advantage of reducing the size, volume, and weight and increasing the overall DC/DC converter system efficiency compared to the single-phase systems.

Asa, Erdem [ORNL] (ORCID:0000000190884812)↗

DOE OSTI2018

Spin current devices and methods of fabrication thereof

Pure spin current devices are provided. The devices include sandwich structures of metal/magnetic insulator/metal. A first current injected in a first metal layer generates a pure spin current. The spin current can be switched between “on” and “off” states by controlling an in-plane magnetization orientation of the magnetic insulator. In the “on” state, the pure spin current is transmitted from the first metal layer to the second metal layer, through the magnetic insulator layer. The pure spin current in the second metal layer induces generation of a second charge current. In the “off” state, the pure spin current is absorbed at the interface between the first metal layer and the metal insulator. Such structures can serve as pure spin current valve devices or provide analog functionality, as rotating the in-plane magnetization provides analog sinusoidal modulation of the spin current.

Shi, Jing↗

DOE OSTI2019

Resolving Detonation NanoDiamond Size Evolution and Morphology at Sub-Microsecond Time-Scales During High-Explosive Detonations

Characterization of the initial morphology of detonation nanodiamond (DND) has been the focus of many research studies that aim to develop fundamental understanding of carbon condensation under extreme conditions. Identifying the pathways of DND formation has the potential for significant impact in many of the controlled synthesis of nanoscale carbon with tailored functionality; currently, a wide range of possible (and conflicting) mechanisms of nucleation and growth have been proposed and further research is essential. Building a comprehensive understanding of DND formation is challenging because it requires in situ characterization on the sub-µs time-scale during a high explosive detonation. In this study, time resolved small angle X-ray scattering (TR-SAXS) is used to reveal the early-stage DND morphology from < 0.1 μs to 6 μs after the detonation front passes through the X-ray beam path. We address the ambiguity of models previously reported for analysis of small angle scattering from DND by comparing (i) in situ, TR-SAXS recorded during early-stage particulate formation and (ii) ex situ SAXS and transmission electron microscopy measurements (TEM) of products recovered from detonation of the same high-explosive within a carefully designed ice chamber. The SAXS from both late-time ( > 1 μs) in situ and recovered DND exhibit consistent features in the I(q) curve. Such close similarity allows a high fidelity SAXS model derived from the ex situ SAXS and TEM measurements to be applied to the in situ data, which yields new insight into the early stage (< 1µs) morphology of DND. Our analysis indicates a size-distribution of DND particles is observed within 0.1 μs post-detonation and have a mean core diameter slightly below 4 nm and surface texture that consists of hemispherical protrusions that extend ~ 1 nm from the surface. Beyond ~ 0.3 μs, the size distribution increases slightly, while the surface texture persists for several microseconds after the detonation. Combined with thermochemical simulations, these results indicate that during detonation of Composition B, carbon is condensed into nanoscale diamond much faster than previously reported in other studies. Furthermore, the surface texture of the DND is shown to arise during condensation rather than via subsequent graphitization.

carbon condensation↗

DOE OSTI2016

Multisource inverse-geometry CT. Part II. X-ray source design and prototype

Purpose: This paper summarizes the development of a high-power distributed x-ray source, or “multisource,” designed for inverse-geometry computed tomography (CT) applications [see B. De Man et al., “Multisource inverse-geometry CT. Part I. System concept and development,” Med. Phys. 43, 4607–4616 (2016)]. The paper presents the evolution of the source architecture, component design (anode, emitter, beam optics, control electronics, high voltage insulator), and experimental validation. Methods: Dispenser cathode emitters were chosen as electron sources. A modular design was adopted, with eight electron emitters (two rows of four emitters) per module, wherein tungsten targets were brazed onto copper anode blocks—one anode block per module. A specialized ceramic connector provided high voltage standoff capability and cooling oil flow to the anode. A matrix topology and low-noise electronic controls provided switching of the emitters. Results: Four modules (32 x-ray sources in two rows of 16) have been successfully integrated into a single vacuum vessel and operated on an inverse-geometry computed tomography system. Dispenser cathodes provided high beam current (>1000 mA) in pulse mode, and the electrostatic lenses focused the current beam to a small optical focal spot size (0.5 × 1.4 mm). Controlled emitter grid voltage allowed the beam current to be varied for each source, providing the ability to modulate beam current across the fan of the x-ray beam, denoted as a virtual bowtie filter. The custom designed controls achieved x-ray source switching in <1 μs. The cathode-grounded source was operated successfully up to 120 kV. Conclusions: A high-power, distributed x-ray source for inverse-geometry CT applications was successfully designed, fabricated, and operated. Future embodiments may increase the number of spots and utilize fast read out detectors to increase the x-ray flux magnitude further, while still staying within the stationary target inherent thermal limitations.

60 APPLIED LIFE SCIENCES↗