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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Transforming Dermatologic Imaging for the Digital Era: Metadata and Standards

Imaging is increasingly being used in dermatology for documentation, diagnosis, and management of cutaneous disease. The lack of standards for dermatologic imaging is an impediment to clinical uptake. Standardization can occur in image acquisition, terminology, interoperability, and metadata. This paper presents the International Skin Imaging Collaboration position on standardization of metadata for dermatologic imaging. Metadata is essential to ensure that dermatologic images are properly managed and interpreted. There are two standards-based approaches to recording and storing metadata in dermatologic imaging. The first uses standard consumer image file formats, and the second is the file format and metadata model developed for the Digital Imaging and Communication in Medicine (DICOM) standard. DICOM would appear to provide an advantage over using consumer image file formats for metadata as it includes all the patient, study, and technical metadata necessary to use images clinically. Whereas, consumer image file formats only include technical metadata and need to be used in conjunction with another actor—for example, an electronic medical record—to supply the patient and study metadata. The use of DICOM may have some ancillary benefits in dermatologic imaging including leveraging DICOM network and workflow services, interoperability of images and metadata, leveraging existing enterprise imaging infrastructure, greater patient safety, and better compliance to legislative requirements for image retention.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

Determining heavy metals in spent compact fluorescent lamps (CFLs) and their waste management challenges: Some strategies for improving current conditions

Highlights: • Heavy metals in spent compact fluorescent lamps (CFLs) determined. • Current waste management condition of CFLs in Iran assessed. • Currently, waste of CFLs is disposed by municipal waste stream in waste landfills. • We propose extended producer responsibility (EPR) for CFLs waste management. - Abstract: From environmental viewpoint, the most important advantage of compact fluorescent lamps (CFLs) is reduction of green house gas emissions. But their significant disadvantage is disposal of spent lamps because of containing a few milligrams of toxic metals, especially mercury and lead. For a successful implementation of any waste management plan, availability of sufficient and accurate information on quantities and compositions of the generated waste and current management conditions is a fundamental prerequisite. In this study, CFLs were selected among 20 different brands in Iran. Content of heavy metals including mercury, lead, nickel, arsenic and chromium was determined by inductive coupled plasma (ICP). Two cities, Tehran and Tabriz, were selected for assessing the current waste management condition of CFLs. The study found that waste generation amount of CFLs in the country was about 159.80, 183.82 and 153.75 million per year in 2010, 2011 and 2012, respectively. Waste generation rate of CFLs in Iran was determined to be 2.05 per person in 2012. The average amount of mercury, lead, nickel, arsenic and chromium was 0.417, 2.33, 0.064, 0.056 and 0.012 mg per lamp, respectively. Currently, waste of CFLs is disposed by municipal waste stream in waste landfills. For improving the current conditions, we propose by considering the successful experience of extended producer responsibility (EPR) in other electronic waste management. The EPR program with advanced recycling fee (ARF) is implemented for collecting and then recycling CFLs. For encouraging consumers to take the spent CFLs back at the end of the products’ useful life, a proportion of ARF (for example, 50%) can be refunded. On the other hand, the government and Environmental Protection Agency should support and encourage recycling companies of CFLs both technically and financially in the first place.

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

Property transformation of graphene with Al{sub 2}O{sub 3} films deposited directly by atomic layer deposition

Al{sub 2}O{sub 3} films are deposited directly onto graphene by H{sub 2}O-based atomic layer deposition (ALD), and the films are pinhole-free and continuously cover the graphene surface. The growth process of Al{sub 2}O{sub 3} films does not introduce any detective defects in graphene, suppresses the hysteresis effect and tunes the graphene doping to n-type. The self-cleaning of ALD growth process, together with the physically absorbed H{sub 2}O and oxygen-deficient ALD environment consumes OH{sup −} bonds, suppresses the p-doping of graphene, shifts Dirac point to negative gate bias and enhances the electron mobility.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Single shot cathode transverse momentum imaging in high brightness photoinjectors

In state of the art photoinjector electron sources, thermal emittance from photoemission dominates the final injector emittance. Therefore, low thermal emittance cathode developments and diagnostics are very important. Conventional thermal emittance measurements for the high gradient gun are time-consuming and thus thermal emittance is not measured as frequently as quantum efficiency during the lifetime of photocathodes, although both are important properties for the photoinjector optimizations. In this paper, a single shot measurement of photoemission transverse momentum, i.e., thermal emittance per rms laser spot size, is proposed for photocathode rf guns. By tuning the gun solenoid focusing, the electrons’ transverse momenta at the cathode are imaged to a downstream screen, which enables a single shot measurement of both the rms value and the detailed spectra of the photoelectrons’ transverse momenta. Both simulations and proof of principle experiments are reported.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

A Sub-Electron-Noise Multi-Channel Cryogenic Skipper-CCD Readout ASIC

The MIDNA application specific integrated circuit (ASIC) is a skipper-CCD readout chip fabricated in a 65 nm LP-CMOS process that is capable of working at cryogenic temperatures. The chip integrates four front-end channels that process the skipper-CCD signal and performs differential averaging using a dual slope integration (DSI) circuit. Each readout channel contains a pre-amplifier, a DC restorer, and a dual-slope integrator with chopping capability. The integrator chopping is a key system design element in order to mitigate the effect of low-frequency noise produced by the integrator itself, and it is not often required with standard CCDs. Each channel consumes 4.5 mW of power, occupies 0.156 mm${^2}$ area and has an input referred noise of 2.7${\mu\nu}_{rms}$. It is demonstrated experimentally to achieve sub-electron noise when coupled with a skipper-CCD by means of averaging samples of each pixel. Here, sub-electron noise is shown in three different acquisition approaches. The signal range is 6000 electrons. The readout system achieves 0.2${e^{-}}$ RMS by averaging 1000 samples with MIDNA both at room temperature and at 180 Kelvin.

1/f noise↗
DOE OSTI2013

Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products, Part 3: LED Environmental Testing

This report covers the third part of a larger U.S. Department of Energy (DOE) project to assess the life- cycle environmental and resource impacts associated with the manufacturing, transport, use, and disposal of light-emitting diode (LED) lighting products in relation to incumbent lighting technologies. All three reports are available on the DOE website (www.ssl.energy.gov/tech_reports.html). Part 1: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps; Part 2: LED Manufacturing and Performance; Part 3: LED Environmental Testing. Parts 1 and 2 were published in February and June 2012, respectively. The Part 1 report included a summary of the life-cycle assessment (LCA) process and methodology, provided a literature review of more than 25 existing LCA studies of various lamp types, and performed a meta-analysis comparing LED lamps with incandescent and compact fluorescent lamps (CFLs). Drawing from the Part 1 findings, Part 2 performed a more detailed assessment of the LED manufacturing process and used these findings to provide a comparative LCA taking into consideration a wider range of environmental impacts. Both reports concluded that the life-cycle environmental impact of a given lamp is dominated by the energy used during lamp operation—the upstream generation of electricity drives the total environmental footprint of the product. However, a more detailed understanding of end-of-life disposal considerations for LED products has become increasingly important as their installation base has grown. The Part 3 study (reported herein) was undertaken to augment the LCA findings with chemical analysis of a variety of LED, CFL, and incandescent lamps using standard testing procedures. A total of 22 samples, representing 11 different models, were tested to determine whether any of 17 elements were present at levels exceeding California or Federal regulatory thresholds for hazardous waste. Notably, this type of testing does not provide an indication of product safety during use. Key findings include: • The selected models were generally found to be below thresholds for Federally regulated elements, although volatile mercury in the CFLs is presumed to have escaped detection; • Nearly all of the lamps (regardless of technology) exceeded at least one California threshold— typically for copper, zinc, antimony, or nickel; • The greatest contributors were the metal screw bases, drivers, ballasts, and wires or filaments— internal LED light sources generally did not cause LED lamps to exceed thresholds. This study was exploratory in nature and was not intended to provide a definitive indication of regulatory compliance for any specific lamp model or technology. Further study would be needed to more broadly characterize the various light source technologies; to more accurately and precisely characterize a specific model; or to determine whether product redesign would be appropriate. However, concentrations of regulated elements in LED lamps were found to be comparable to cell phones and other types of electronic devices, which like incandescent lamps and CFLs have also have been shown to exceed the stringent California thresholds for hazardous waste. Although LED lamps offer reduced life-cycle energy and environmental impacts when compared to CFLs and incandescent lamps, recycling will likely gain importance as consumer adoption of this emerging technology continues to increase.

bulb↗
DOE OSTI2021

RCSB Protein Data Bank: Celebrating 50 years of the PDB with new tools for understanding and visualizing biological macromolecules in 3D

We report the Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB), funded by the US National Science Foundation, National Institutes of Health, and Department of Energy, has served structural biologists and Protein Data Bank (PDB) data consumers worldwide since 1999. RCSB PDB, a founding member of the Worldwide Protein Data Bank (wwPDB) partnership, is the US data center for the global PDB archive housing biomolecular structure data. RCSB PDB is also responsible for the security of PDB data, as the wwPDB-designated Archive Keeper. Annually, RCSB PDB serves tens of thousands of three-dimensional (3D) macromolecular structure data depositors (using macromolecular crystallography, nuclear magnetic resonance spectroscopy, electron microscopy, and micro-electron diffraction) from all inhabited continents. RCSB PDB makes PDB data available from its research-focused RCSB.org web portal at no charge and without usage restrictions to millions of PDB data consumers working in every nation and territory worldwide. In addition, RCSB PDB operates an outreach and education PDB101.RCSB.org web portal that was used by more than 800,000 educators, students, and members of the public during calendar year 2020. This invited Tools Issue contribution describes (i) how the archive is growing and evolving as new experimental methods generate ever larger and more complex biomolecular structures; (ii) the importance of data standards and data remediation in effective management of the archive and facile integration with more than 50 external data resources; and (iii) new tools and features for 3D structure analysis and visualization made available during the past year via the RCSB.org web portal.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

An Analytic Network Process approach for the environmental aspect selection problem — A case study for a hand blender

Life Cycle Assessment is a tool to assess, in a systematic way, the environmental aspects and its potential environmental impacts and resources used throughout a product's life cycle. It is widely accepted and considered as one of the most powerful tools to support decision-making processes used in ecodesign and sustainable production in order to learn about the most problematic parts and life cycle phases of a product and to have a projection for future improvements. However, since Life Cycle Assessment is a cost and time intensive method, companies do not intend to carry out a full version of it, except for large corporate ones. Especially for small and medium sized enterprises, which do not have enough budget for and knowledge on sustainable production and ecodesign approaches, focusing only on the most important possible environmental aspect is unavoidable. In this direction, finding the right environmental aspect to work on is crucial for the companies. In this study, a multi-criteria decision-making methodology, Analytic Network Process is proposed to select the most relevant environmental aspect. The proposed methodology aims at providing a simplified environmental assessment to producers. It is applied for a hand blender, which is a member of the Electrical and Electronic Equipment family. The decision criteria for the environmental aspects and relations of dependence are defined. The evaluation is made by the Analytic Network Process in order to create a realistic approach to inter-dependencies among the criteria. The results are computed via the Super Decisions software. Finally, it is observed that the procedure is completed in less time, with less data, with less cost and in a less subjective way than conventional approaches. - Highlights: • We present a simplified environmental assessment methodology to support LCA. • ANP is proposed to select the most relevant environmental aspect. • ANP deals well with the interdependencies between aspects and impacts. • The methodology is less subjective, less complicated, and less time–money consuming. • The proposed methodology is suitable for use by SMEs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Reduction of Plutonium(VI) to (V) by Hydroxamate Compounds at Environmentally Relevant pH

Natural organic matter is known to influence the mobility of plutonium (Pu) in the environment via complexation and reduction mechanisms. Hydroxamate siderophores have been specifically implicated due to their strong association with Pu. Hydroxamate siderophores can also break down into di and mono-hydroxamates and may influence Pu oxidation state, and thereby its mobility. In this study we explored the reactions of Pu(VI) and Pu(V) with a mono-hydroxamate compound (acetohydroxamic acid, AHA) and a tri-hydroxamate siderophore desferrioxamine B (DFOB) at environmentally relevant pH (5.5-8.2). Pu(VI) was instantaneously reduced to Pu(V) upon reaction with AHA. The presence of hydroxylamine was not observed at these pHs; however, AHA was consumed during the reaction. This suggests that the reduction of Pu(VI) to Pu(V) by AHA is facilitated by direct one electron transfer. Importantly, further reduction to Pu(IV) or Pu(III) was not observed, even with excess AHA. We believe that further reduction of Pu(V) did not occur because Pu(V) does not form a strong complex with hydroxamate compounds at circum-neutral pH. Experiments performed using desferrioxamine B (DFOB) yielded similar results. Broadly, this suggests that Pu(V) reduction to Pu(IV) in the presence of natural organic matter is not facilitated by hydroxamate functional groups and that other natural organic matter moieties likely play a more prominent role.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Evolution of dislocation substructures in metals via high-strain-rate nanoindentation

Deformation at high strain rates often results in high stresses on many engineering materials, potentially leading to catastrophic failure without proper design. High-strain-rate mechanical testing is thus needed to improve the design of future structural materials for a wide range of applications. Although several high-strain-rate mechanical testing techniques have been developed to provide a fundamental understanding of material responses and microstructural evolution under high-strain-rate deformation conditions, these tests are often very time consuming and costly. In this work, we utilize a high-strain-rate nanoindentation testing technique and system in combination with transmission electron microscopy to reveal the deformation mechanisms and dislocation substructures that evolve in pure metals from low (10 –2 s –1 ) to very high indentation strain rates (10 4 s –1 ), using face-centered cubic aluminum and body-centered cubic molybdenum as model materials. The results help to establish the conditions under which micro- and macro-scale tests can be compared with validity and also provide a promising pathway that could lead to accelerated high-strain-rate testing at substantially reduced costs.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Latent uncertainties of the precalculated track Monte Carlo method

Purpose: While significant progress has been made in speeding up Monte Carlo (MC) dose calculation methods, they remain too time-consuming for the purpose of inverse planning. To achieve clinically usable calculation speeds, a precalculated Monte Carlo (PMC) algorithm for proton and electron transport was developed to run on graphics processing units (GPUs). The algorithm utilizes pregenerated particle track data from conventional MC codes for different materials such as water, bone, and lung to produce dose distributions in voxelized phantoms. While PMC methods have been described in the past, an explicit quantification of the latent uncertainty arising from the limited number of unique tracks in the pregenerated track bank is missing from the paper. With a proper uncertainty analysis, an optimal number of tracks in the pregenerated track bank can be selected for a desired dose calculation uncertainty. Methods: Particle tracks were pregenerated for electrons and protons using EGSnrc and GEANT4 and saved in a database. The PMC algorithm for track selection, rotation, and transport was implemented on the Compute Unified Device Architecture (CUDA) 4.0 programming framework. PMC dose distributions were calculated in a variety of media and compared to benchmark dose distributions simulated from the corresponding general-purpose MC codes in the same conditions. A latent uncertainty metric was defined and analysis was performed by varying the pregenerated track bank size and the number of simulated primary particle histories and comparing dose values to a “ground truth” benchmark dose distribution calculated to 0.04% average uncertainty in voxels with dose greater than 20% of D{sub max}. Efficiency metrics were calculated against benchmark MC codes on a single CPU core with no variance reduction. Results: Dose distributions generated using PMC and benchmark MC codes were compared and found to be within 2% of each other in voxels with dose values greater than 20% of the maximum dose. In proton calculations, a small (≤1 mm) distance-to-agreement error was observed at the Bragg peak. Latent uncertainty was characterized for electrons and found to follow a Poisson distribution with the number of unique tracks per energy. A track bank of 12 energies and 60000 unique tracks per pregenerated energy in water had a size of 2.4 GB and achieved a latent uncertainty of approximately 1% at an optimal efficiency gain over DOSXYZnrc. Larger track banks produced a lower latent uncertainty at the cost of increased memory consumption. Using an NVIDIA GTX 590, efficiency analysis showed a 807 × efficiency increase over DOSXYZnrc for 16 MeV electrons in water and 508 × for 16 MeV electrons in bone. Conclusions: The PMC method can calculate dose distributions for electrons and protons to a statistical uncertainty of 1% with a large efficiency gain over conventional MC codes. Before performing clinical dose calculations, models to calculate dose contributions from uncharged particles must be implemented. Following the successful implementation of these models, the PMC method will be evaluated as a candidate for inverse planning of modulated electron radiation therapy and scanned proton beams.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2024

Machine Learning for Predictive Performance Analysis in Charged Particle Beam Tools

Imaging methods driven by probes, electrons, and ions have played a dominant role in modern science and engineering. Opportunities for machine vision and AI that focus on consumer problems like driving and feature recognition, are now presenting themselves for automating aspects of the scientific processes. This proposal aims to enable and drive discovery in ultra-low energy implantation by taking advantage of faster processing, flexible control and detection methods, and architecture-agnostic workflows that will result in higher efficiency and shorter scientific development cycles. Custom microscope control, collection and analysis hardware will provide a framework for conducting novel in situ experiments revealing unprecedented insight into surface dynamics at the nanoscale. Ion implantation is a key capability for the semiconductor industry. As devices shrink, novel materials enter the manufacturing line, and quantum technologies transition to being more mainstream. Traditional implantation methods fall short in terms of energy, ion species, and positional precision. Here we demonstrate 1 keV focused ion beam Au implantation into Si and validate the results via atom probe tomography. We show the Au implant depth at 1 keV is 0.8 nm and that identical results for low energy ion implants can be achieved by either lowering the column voltage, or decelerating ions using bias – while maintaining a sub-micron beam focus. We compare our experimental results to static calculations using SRIM and dynamic calculations using binary collision approximation codes TRIDYN and IMSIL. A large discrepancy between the static and dynamic simulation is found that is due to lattice enrichment with high stopping power Au and surface sputtering. Additionally, we demonstrate how model details are particularly important to the simulation of these low-energy heavy-ion implantations. Finally, we discuss how our results pave a way to much lower implantation energies, while maintaining high spatial resolution.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Isolation and characterization of a CO2-tolerant Lactobacillus strain from Crystal Geyser, Utah, U.S.A.

When CO 2 is sequestered into the deep subsurface, changes to the subsurface microbial community will occur. Capnophiles, microorganisms that grow in CO 2 -rich environments, are some organisms that may be selected for under the new environmental conditions. To determine whether capnophiles comprise an important part of CO 2 -rich environments, an isolate from Crystal Geyser, Utah, U.S.A., a CO 2 - rich spring considered a carbon sequestration analog, was characterized. The isolate was cultured under varying CO 2 , pH, salinity, and temperature, as well as different carbon substrates and terminal electron acceptors (TEAs) to elucidate growth conditions and metabolic activity. Designated CG-1, the isolate is related (99%) to Lactobacillus casei in 16S rRNA gene identity, growing at PCO 2 between 0 and 1.0 MPa. Growth is inhibited at 2.5 MPa, but stationary phase cultures exposed to this pressure survive beyond 5 days. At 5.0 MPa, survival is at least 24 h. CG-1 grows in neutral pH, 0.25 M NaCl, and between 25° and 45°C and consumes glucose, lactose, sucrose, or crude oil, likely performing lactic acid fermentation. Fatty acid profiles between 0.1 and 1.0 MPa suggests decreases in cell size and increases in membrane rigidity. Transmission electron microscopy reveals rod shaped bacteria at 0.1 MPa. At 1.0 MPa, cells are smaller, amorphous, and produce abundant capsular material. Its ability to grow in environments regardless of the presence of CO 2 suggests we have isolated an organism that is more capnotolerant than capnophilic. Results also show that microorganisms are capable of surviving the stressful conditions created by the introduction of CO 2 for sequestration. Furthermore, our ability to culture an environmental isolate indicates that organisms found in CO 2 environments from previous genomic and metagenomics studies are viable, metabolizing, and potentially affecting the surrounding environment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Characterizations Of Precipitate Phases In a Ti-Ni-Pd Alloy

Precipitates in the Ti46Ni37.5Pd16.5 alloy were investigated by electron diffraction and high-resolution scanning transmission electron microscopy. The phase content and stability were determined at several different temperatures and times. Aging at 400 C for an hour results in a new phase, which is consumed by P-phase at longer aging time. At 450 C, the new phase appears first, and then coexists with P-phase. At 500 C, the entire alloy transformed into the new phase. At 550 C, Ti3(Ni,Pd)4 phase begins to form.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Pseudomonas sp. Strain 273 Degrades Fluorinated Alkanes

Fluorinated organic compounds have emerged as environmental constituents of concern. We demonstrate that the alkane degrader Pseudomonas sp. strain 273 utilizes terminally monofluorinated C 7 –C 10 alkanes and 1,10-difluorodecane (DFD) as the sole carbon and energy sources in the presence of oxygen. Strain 273 degraded 1-fluorodecane (FD) (5.97 ± 0.22 mM, nominal) and DFD (5.62 ± 0.13 mM, nominal) within 7 days of incubation, and 92.7 ± 3.8 and 90.1 ± 1.9% of the theoretical maximum amounts of fluorine were recovered as inorganic fluoride, respectively. With n-decane, strain 273 attained (3.24 ± 0.14) × 10 7 cells per μmol of carbon consumed, while lower biomass yields of (2.48 ± 0.15) × 10 7 and (1.62 ± 0.23) × 10 7 cells were measured with FD or DFD as electron donors, respectively. The organism coupled decanol and decanoate oxidation to denitrification, but the utilization of (fluoro)alkanes was strictly oxygen-dependent, presumably because the initial attack on the terminal carbon requires oxygen. Fluorohexanoate was detected as an intermediate in cultures grown with FD or DFD, suggesting that the initial attack on the fluoroalkanes can occur on the terminal methyl or fluoromethyl groups. Overall, the findings indicate that specialized bacteria such as Pseudomonas sp. strain 273 can break carbon–fluorine bonds most likely with oxygenolytic enzyme systems and that terminally monofluorinated alkanes are susceptible to microbial degradation. The findings have implications for the fate of components associated with aqueous film-forming foam (AFFF) mixtures.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Autonomous Synthesis and Inverse Design of Electrochromic Polymers with High Efficiency and Accuracy

Here, the design and synthesis of functional polymers, aimed at targeted properties through specific structures, have long been challenged by their complex and often nonlinear structure–property relationships. Key processes, including knowledge accumulation for predictive design and experimental refinement and validation, are traditionally labor-insensitive and time-consuming, making it difficult to balance accuracy and efficiency. Here, we introduce an accelerated, autonomous system for the on-demand synthesis of electronic polymers that achieves the desired electrochromic functionality with high accuracy and efficiency. Our approach leverages large language model-assisted data mining, a physics-informed copolymer machine learning model, and an AI-driven autonomous robotic workflow in the Polybot lab. Within 72 h, Polybot autonomously synthesized electrochromic polymers (ECPs) with targeted, previously-unreported color values, including green polymers with specific absorption profiles, precisely fine-tuning copolymer structures with a 5% step size in comonomer composition within a three-monomer system. A publicly accessible ECP informatics database has also been created to foster knowledge exchange.

AI-driven Robotic Lab↗
DOE OSTI2016

Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures

Significance Rare earth metals, La–Lu, Sc, and Y, are essential components of electronic materials and permanent magnets in diverse technologies. But, their mining and separations chemistry are unsustainable and plagued with supply problems. Recycling of consumer materials containing rare earths is a promising new source of these critical materials but similarly requires efficient separations. We report the use of a tripodal hydroxylaminato ligand, TriNOx 3– , with rare earth cations that enable fast, efficient separations through a simple leaching process. This approach is expected to contribute to a new method for recycling postconsumer materials including lighting phosphors and magnets, to diversify and improve the sustainability of the rare earth metal supply chain.

36 MATERIALS SCIENCE↗
DOE OSTI2018

A Soft-Matter Biomolecular Memristor Synapse for Neuromorphic Systems

The goal of neuromorphic computing is to recreate the computational power and efficiency of the human brain with circuitry. The ability of the brain to solve complex real time tasks, while consuming 20 W of power on average, is made possible through its connection density, adaptability, and parallel processing. Recreating these features using traditional electronics circuit elements is incredibly difficult, and therefore, soft-matter memristors made of biomolecules similar to those found in biological synapses and capable of emulating various synaptic features can be used as neuromorphic hardware. In this work, we introduce and experimentally demonstrate an electronic neuron circuit capable of interacting with ionic, soft-matter memristors. These memristors are proven to exhibit short-term plasticity, especially paired-pulse facilitation and depression found in presynaptic terminals - features that are not found in state-of-the-art solid-state memristors. We make use of these features for applications in online learning by developing a synapse-neuron circuit which implements spike-rate-dependent plasticity (SRDP) as a learning function.

Weiss, Ryan↗