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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 OSTI2014

MO-G-BRF-02: Enhancement of Texture-Based Metastasis Prediction Models Via the Optimization of PET/MRI Acquisition Protocols

Purpose: We have previously identified a prediction model of lung metastases at diagnosis of soft-tissue sarcomas (STS) that is composed of two textural features extracted from FDG-PET and T1-weighted (T1w) MRI scans. The goal of this study is to evaluate whether the optimization in FDGPET and MRI acquisition parameters would enhance the prediction performance of texture-based models. Methods: Ten FDG-PET and T1w- MRI digitized tumor models were generated from imaging data of STS patients who underwent pre-treatment clinical scans between 2005 and 2011. Five of ten patients eventually developed lung metastases. Numerically simulated MR images were produced using echo times (TE) of 2 and 4 times the nominal clinical parameter (TEc), and repetition times (TR) of 0.5, 0.67, 1.5 and 2 times the nominal clinical parameter (TRc) found in the DICOM headers (TEc range: 9–13 ms, TRc range: 410-667 ms). PET 2D images were simulated using Monte-Carlo and were reconstructed using an ordered-subsets expectation maximization (OSEM) algorithm with 1 to 32 iterations and a post-reconstruction Gaussian filter of 0, 2, 4 or 6 mm width. For all possible combinations of PET and MRI acquisition parameters, the prediction model was constructed using logistic regression with new coefficients, and its associated prediction performance for lung metastases was evaluated using the area under the ROC curve (AUC). Results: The prediction performance over all simulations yielded AUCs ranging from 0.7 to 1. Notably, TR values below or equal to TRc and higher PET post-reconstruction filter widths yielded higher prediction performance. The best results were obtained with a combination of 4*TEc, TRc, 30 OSEM iterations and 2mm filter width. Conclusion: This work indicates that texture-based metastasis prediction models could be improved using optimized choices of FDG-PET and MRI acquisition protocols. This principle could be generalized to other texture-based models.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

A matter of quantum voltages

Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V{sub o}) – the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V{sub o} from quantum calculations. Voltages are very sensitive to the distribution of electrons and provide metrics to understand interactions in condensed phases. In the present study, we find excellent agreement with measurements of V{sub o} for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V{sub o} as well as the fluctuations of these voltages in aqueous NaCl electrolytes and characterize the changes in their behavior as the resolution increases below the size of atoms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Compositional dependence of antiferromagnetic anisotropy in IrMn/CoFe exchange bias systems

We report on a study of the effect of Ir content on the loop shift (H{sub EX}) and anisotropy constant (K{sub AF}) in the CoFe/IrMn system. The sample structure investigated was Si/NiCr(5 nm)/Ru(5 nm)/Ir{sub x}Mn{sub 1-x}/CoFe(2 nm)/Ta(3 nm). All samples were produced by sputtering and the Ir and Mn levels were varied using a specially made composite target and deposited at {approx}120 deg. C. The composition of the samples was analyzed using energy dispersive x-ray analysis. K{sub AF} was calculated from thermal activation measurements using the York Protocols. A plateau in H{sub EX} was found for Ir levels between 16- 20.5 at. %. H{sub EX} was found to decrease by 50% on either side of this window. This result is consistent with previous studies where the enhancement of H{sub EX} was attributed to an increase in the atomic ordering of the IrMn alloy. However, K{sub AF} decreases linearly with increasing Ir concentration and does not appear to correlate with the change in H{sub EX}.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Investigation of Path Dependence in Commercial Li-ion Cells Chosen for PHEV Duty Cycle Protocols (paper)

Path dependence is emerging as a premier issue of how electrochemical cells age in conditions that are diverse and variable in the time domain. For example, lithium-ion cells in a vehicle configuration will experience a variable combination of usage and rest periods over a range of temperature and state of charge (SOC). This is complicated by the fact that some aging can actually become worse (or better) when a lithium-ion cell is idle for extended periods under calendar-life (calL) aging, as opposed to cycle-life (cycL) conditions where the cell is used within a predictable schedule. The purpose of this study is to bridge the gap between highly idealized and controlled laboratory test conditions and actual field conditions regarding PHEV applications, so that field-type aging mechanisms can be mimicked and quantified in a repeatable laboratory setting. The main parameters are the magnitude and frequency of the thermal cycling, looking at isothermal, mild, and severe scenarios. To date, little is known about Li-ion aging effects caused by thermal cycling superimposed onto electrochemical cycling, and related path dependence. This scenario is representative of what Li-ion batteries will experience in vehicle service, where upon the typical start of a HEV/PHEV, the batteries will be cool or cold, will gradually warm up to normal temperature and operate there for a time, then will cool down after the vehicle is turned off. Such thermal cycling will occur thousands of times during the projected life of a HEV/PHEV battery pack. We propose to quantify the effects of thermal cycling on Li-ion batteries using a representative chemistry that is commercially available. The secondary Li-ion cells used in this study are of the 18650 configuration, have a nominal capacity rating of 1.9 Ah, and consist of a {LiMn2O4 + LiMn(1/3)Ni(1/3)Co(1/3)O2} cathode and a graphite anode. Electrochemical cycling is based on PHEV-relevant cycle-life protocols that are a combination of charge depleting (CD) and charge sustaining (CS) modes discussed in the Battery Test Manual for Plug-in Hybrid Electric Vehicles (INL, March 2008, rev0). A realistic duty cycle will involve both CD and CS modes, the proportion of each defined by the severity of the power demands. We assume that the cells will start each cycling day at 90% SOC, and that they will not be allowed to go below 35% SOC, with operation around 70% SOC being a nominal condition. The 35, 70, and 90% SOC conditions are also being used to define critical aspects of the related reference performance test (RPT) for this investigation. There are three primary components to the RPT, all assessed at room temperature: (A) static and residual capacity (SRC) over a matrix of current, (B) kinetics and pulse performance testing (PPT) over current for SOCs of interest, and (C) EIS for SOCs of interest. The RPT is performed on all cells every 30 day test interval, as well as a pulse-per-day to provide a quick diagnostic snapshot. Where feasible, we utilize various elements of Diagnostic Testing (DT) to characterize performance of the cells and to gain mechanistic-level knowledge regarding both performance features and limitations. We will present the rationale behind the experimental design, early data, and discuss the fundamental tools used to elucidate performance degradation mechanisms.

25 ENERGY STORAGE↗
DOE OSTI2024

Merged Observatory Data Files (MODFs): an integrated observational data product supporting process-oriented investigations and diagnostics

A large and ever-growing body of geophysical information is measured in campaigns and at specialized observatories as a part of scientific expeditions and experiments. These collections of observed data include many essential climate variables (as defined by the Global Climate Observing System) but are often distinguished by a wide range of additional non-routine measurements that are designed to not only document the state of the environment but also the drivers that contribute to that state. These field data are used not only to further understand environmental processes through observation-based studies but also to provide baseline data to test model performance and to codify understanding to improve predictive capabilities. To address the considerable barriers and difficulty in utilizing these diverse and complex data for observation–model research, the Merged Observatory Data File (MODF) concept has been developed. A MODF combines measurements from multiple instruments into a single file that complies with well-established data format and metadata practices and has been designed to parallel the development of corresponding Merged Model Data Files (MMDFs). Using the MODF and MMDF protocols will facilitate the evolution of model intercomparison projects into model intercomparison and improvement projects by putting observation and model data “on the same page” in a timely manner. The MODF concept was developed especially for weather forecast model studies in the Arctic. The surprisingly complex process of implementing MODFs in that context refined the concept itself. Thus, this article explains the concept of MODFs by providing details on the issues that were revealed and resolved during that first specific implementation. Detailed instructions are provided on how to make MODFs, and this article can be considered a MODF creation manual.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

A Study of Cost-Saving Potential of Load Flexibility Measures in Grid-Interactive Multifamily Buildings

With recent advances in smart technologies, more and more smart devices are penetrating the residential and commercial buildings market. The introduction of these smart devices is also helping IoT companies emerge with load aggregator roles in the sector. With more utility companies on the track of supporting OpenADR protocols, the aggregators could play a significant role in providing load flexibilities by automatically responding to demand response (DR) events and coordinating load flexibility measures between customers. This would benefit utility companies by reducing stress on the grid during critical peak demand hours as well as customers by allowing them to utilize utility rate structures advantageous to those able to reduce electric usage during high-demand hours. This study evaluates cost and energy savings from adopting multiple load flexibility measures in multifamily buildings. Combinations of different load flexibility measures, including space temperature floating, light dimming, automatic window shading, and water heater temperature floating, are considered. The simulations are performed using OpenStudio®, an open-source U.S. Department of Energy (DOE) simulation platform. For the case study, we used a midrise apartment building with weather conditions from Denver, Colorado. To compare climate zone differences, simulations were also performed for Los Angeles, California, and Chicago, Illinois. Initial results indicate that the application of automated load flexibility measures without careful consideration of dispatching strategies and DR program enrollments could significantly affect the savings. To get meaningful cost savings, aggregators need to encourage tenant awareness to curtail energy usage through occupant behavior in addition to dispatching automatic load flexibility measures. The outcomes from this study are believed to help load aggregators understand the risks and benefits of load flexibility opportunities.

building energy modeling↗
DOE OSTI2016

Performance characteristics of dedicated molecular breast imaging systems at low doses

Purpose: The purpose of this study was to compare the system performance characteristics and lesion detection capability of two molecular breast imaging (MBI) systems: a multicrystal sodium iodide (NaI)-based single-head system and a cadmium zinc telluride (CZT)-based dual-head system at low administered doses (150–300 MBq) of Tc-99m sestamibi. Methods: System performance characteristics including count sensitivity, uniformity, energy resolution, and spatial resolution were measured using standard NEMA methods, or a modified version thereof in cases where the standard NEMA protocol could not be applied. A contrast-detail phantom with 48 lesions at varying depths from the collimator surface was used to assess lesion contrast-to-noise-ratio (CNR) using background count densities comparable to those observed in patient studies performed with administered doses of 150 MBq Tc-99m sestamibi. Lesions with CNR >3 were deemed to be detectable. Thirty patients undergoing MBI examinations with administered doses of 150–300 MBq were scanned for an additional view on the pixelated NaI system. CNR was calculated for lesions observed on patient images. Background count densities of patient images were measured and compared between the two systems. Results: Over the central field of view, integral and differential uniformity were 6.1% and 4.2%, respectively, for the pixelated NaI system, and 3.8% and 2.7%, respectively, for the CZT system. Count sensitivity was 10.8 kcts/min/MBq for the NaI system and 32.9 kcts/min/MBq for the CZT system. Energy resolution was 13.5% on the pixelated NaI system and 4.5% on the CZT system. Spatial resolution (full-width at half-maximum) for the pixelated NaI detector was 4.2 mm at a distance of 1.2 cm from the collimator and 5.2 mm at 3.1 cm. Spatial resolution of a single CZT detector was 2.9 mm at a distance of 1.2 cm from the collimator and 4.7 mm at 3.1 cm. Effective spatial resolution obtained with dual-head CZT was below 4.7 mm throughout a simulated breast thickness of 6 cm. From contrast-detail phantom images of lesions at distances of 1.5–4.5 cm from the collimator face, the CZT system detected 124 of 144 (86%) of lesions compared to 97 of 144 (67%) with the NaI system. In patient studies, from comparison of the same view with both systems, a total of 7 breast lesions were identified on CZT system in seven patients, and 4 of 7 (57%) were detected on NaI system. Patient image background count densities on the CZT system were on average 3.4 times higher than those on the NaI system. Conclusions: The CZT system demonstrated better uniformity, count sensitivity, spatial resolution, energy resolution, and lesion detection in phantom and patient studies compared to the NaI system. At administered doses of 150–300 MBq Tc-99m sestamibi, patient results obtained with CZT systems may not be directly translatable to NaI systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

A new treatment for human malignant melanoma targeting L-type amino acid transporter 1 (LAT1): A pilot study in a canine model

Highlights: •LAT1 is highly expressed in tumors but at low levels in normal tissues. •We examine LAT1 expression and function in malignant melanoma (MM). •LAT1 expression in MM tissues and cell lines is higher than those in normal tissues. •LAT1 selective inhibitors inhibit amino acid uptake and cell growth in MM cells. •New chemotherapeutic protocols including LAT1 inhibitors are effective for treatment. -- Abstract: L-type amino acid transporter 1 (LAT1), an isoform of amino acid transport system L, transports branched or aromatic amino acids essential for fundamental cellular activities such as cellular growth, proliferation and maintenance. This amino acid transporter recently has received attention because of its preferential and up-regulated expression in a variety of human tumors in contrast to its limited distribution and low-level expression in normal tissues. In this study, we explored the feasibility of using LAT1 inhibitor as a new therapeutic agent for human malignant melanomas (MM) using canine spontaneous MM as a model for human MM. A comparative study of LAT expression was performed in 48 normal tissues, 25 MM tissues and five cell lines established from MM. The study observed LAT1 mRNA levels from MM tissues and cell lines that were significantly (P < 0.01) higher than in normal tissues. Additionally, MM with distant metastasis showed a higher expression than those without distant metastasis. Functional analysis of LAT1 was performed on one of the five cell lines, CMeC-1. [{sup 3}H]L-Leucine uptake and cellular growth activities in CMeC-1 were inhibited in a dose-dependent manner by selective LAT1 inhibitors (2-amino-2-norbornane-carboxylic acid, BCH and melphalan, LPM). Inhibitory growth activities of various conventional anti-cancer drugs, including carboplatin, cyclophosphamide, dacarbazine, doxorubicin, mitoxantrone, nimustine, vinblastine and vincristine, were significantly (P < 0.05) enhanced by combination use with BCH or LPM. These findings suggest that LAT1 could be a new therapeutic target for MM.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Analysis of the static magnetic field-dependent optical transmission of Ni nanorod colloidal suspensions

The magnetic field-dependent optical transmission of dilute Ni nanorod aqueous suspensions was investigated. A series of four samples of nanorods were synthesized using the AAO template method and processed to stable colloids. The distributions of their length and diameter were characterized by analysis of TEM images and revealed average diameters of ∼25 nm and different lengths in the range of 60 nm–1100 nm. The collinear magnetic and optical anisotropy was studied by static field-dependent transmission measurements of linearly polarized light parallel and perpendicular to the magnetic field direction. The experimental results were modelled assuming the field-dependent orientation distribution function of a superparamagnetic ensemble for the uniaxial ferromagnetic nanorods in liquid dispersion and extinction cross sections for longitudinal and transversal optical polarization derived from different approaches, including the electrostatic approximation and the separation of variables method, both applied to spheroidal particles, as well as finite element method simulations of spheroids and capped cylindrical particles. The extinction cross sections were compared to reveal the differences associated with the approximations of homogeneous polarization and/or particle shape. The consequences of these approximations for the quantitative analysis of magnetic field-dependent optical transmission measurements were investigated and a reliable protocol derived. Furthermore, the changes in optical cross sections induced by electromagnetic interaction between two nanorods in parallel end-to-end and side-by-side configuration as a function of their separation were studied.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

TU-EF-204-10: A Preliminary Study Evaluating Calculation Variations of Local Noise Power Spectra for CT Simulation in Radiation Therapy

Purpose: Local noise power spectrum (NPS) properties are significantly affected by calculation variables and CT acquisition and reconstruction parameters, but a thoughtful analysis of these effects is absent. In this study, we performed a complete analysis of the effects of calculation and imaging parameters on the NPS. Methods: The uniformity module of a Catphan phantom was scanned with a Philips Brilliance 64-slice CT simulator using various scanning protocols. Images were reconstructed using both FBP and iDose4 reconstruction algorithms. From these images, local NPS were calculated for regions of interest (ROI) of varying locations and sizes, using four image background removal methods. Additionally, using a predetermined ground truth, NPS calculation accuracy for various calculation parameters was compared for computer simulated ROIs. A complete analysis of the effects of calculation, acquisition, and reconstruction parameters on the NPS was conducted. Results: The local NPS varied with ROI size and image background removal method, particularly at low spatial frequencies. The image subtraction method was the most accurate according to the computer simulation study, and was also the most effective at removing low frequency background components in the acquired data. However, first-order polynomial fitting using residual sum of squares and principle component analysis provided comparable accuracy under certain situations. Similar general trends were observed when comparing the NPS for FBP to that of iDose4 while varying other calculation and scanning parameters. However, while iDose4 reduces the noise magnitude compared to FBP, this reduction is spatial-frequency dependent, further affecting NPS variations at low spatial frequencies. Conclusion: The local NPS varies significantly depending on calculation parameters, image acquisition parameters, and reconstruction techniques. Appropriate local NPS calculation should be performed to capture spatial variations of noise; calculation methodology should be selected with consideration of image reconstruction effects and the desired purpose of CT simulation for radiotherapy tasks.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Durability of Highly Active PGM Catalyst MEA Tested Via Nitrogen and Air AST Cycling Under HDV Condition

PEMFCs are widely considered as the most promising power sources, particularly for heavy-duty vehicles (HDVs). Unfortunately, the degradation of MEAs under HDV condition remains insufficiently studied. In this work, we systematically investigated two MEAs with catalysts of Pt nanoparticles (NPs) supported over high surface area carbon black. These MEAs were tested for durability under HDV condition in nitrogen using a DOE AST protocol for 180,000 cycles, which is equivalent to 30,000 hours or 1 million miles of operation. The commercial Catalyst MEA also underwent 6,000 AST cycles in air under M2FCT condition. We comprehensively investigated the degradation of catalysts. Our results indicate that both MEAs undergo continuous performance degradation in H 2 /air and H 2 /O 2 during the AST cycling in nitrogen, where analysis employing scanning transmission electron microscopy (STEM) and inductively coupled plasma mass spectrometry (ICP-MS) reveal significant degradation behavior for Pt catalysts. The MEA exhibits more significant degradation, especially within mass transfer region, during the AST process in air. In conclusion, this study describes the long-term degradation behavior and mechanism with AST cycling in nitrogen or air governing highly efficient and durable PGM-catalyst MEA design under HDV conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Adult Rhabdomyosarcoma Survival Improved With Treatment on Multimodality Protocols

Purpose: Rhabdomyosarcoma (RMS) is a pediatric sarcoma rarely occurring in adults. For unknown reasons, adults with RMS have worse outcomes than do children. Methods and Materials: We analyzed data from all patients who presented to Memorial Sloan-Kettering Cancer Center between 1990 and 2011 with RMS diagnosed at age 16 or older. One hundred forty-eight patients met the study criteria. Ten were excluded for lack of adequate data. Results: The median age was 28 years. The histologic diagnoses were as follows: embryonal 54%, alveolar 33%, pleomorphic 12%, and not otherwise specified 2%. The tumor site was unfavorable in 67% of patients. Thirty-three patients (24%) were at low risk, 61 (44%) at intermediate risk, and 44 (32%) at high risk. Forty-six percent were treated on or according to a prospective RMS protocol. The 5-year rate of overall survival (OS) was 45% for patients with nonmetastatic disease. The failure rates at 5 years for patients with nonmetastatic disease were 34% for local failure and 42% for distant failure. Among patients with nonmetastatic disease (n=94), significant factors associated with OS were histologic diagnosis, site, risk group, age, and protocol treatment. On multivariate analysis, risk group and protocol treatment were significant after adjustment for age. The 5-year OS was 54% for protocol patients versus 36% for nonprotocol patients. Conclusions: Survival in adult patients with nonmetastatic disease was significantly improved for those treated on RMS protocols, most of which are now open to adults.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
NASA NTRS2021

Characterization Study of TestBed Infrastructure Performance in a Distributed Simulation Environment: Baseline Analysis

Characterization of the performance of Air Traffic Management Exploration (ATM-X) TestBed integration environment has been investigated and documented for one system configuration for progressively increasing traffic. Several statistical parameters were used to assess the performance of the TestBed distributed system such as mean, standard deviation, skewness, and kurtosis of latency, and update rate for aircraft state messages that are transmitted through the simulated system under investigation. It is necessary to assess the performance characteristics of distributed systems in terms of the indicated statistical parameters mentioned above. It is critical to verify the system performance with respect to a researcher’s required system performance. Computer host specifications are documented in terms of Central Processing Unit (CPU) clock speed and core count. Transmission Control Protocol/ Internet Protocol (TCP/IP) message protocol was used for data transmission. The system network topology also contributes to the latency and update rate variations from the one imposed by the data source. The motivation for selecting the TestBed infrastructure as the focus of this study can be attributed to the number of services and capabilities it provides that help simplify the process of preparing and conducting a simulation. These capabilities include an easy to use GUI for simulation configuration, access to TestBed library by the end-user of other simulation software components, a modular adapter paradigm that allows simple connectivity of external software to TestBed, connectivity with other simulation laboratories, and a Software Development Kit (SDK) for quicker development. Two types of traffic generators, Air Traffic Generator (ATG) and Multi Aircraft Control System (MACS) were used to generate messages that were injected into the TestBed distributed environment. Eight different air traffic scenarios with progressively increasing loads were generated for each air traffic simulator. The corresponding air traffic loads between the two simulators had an identical number of aircraft per scenario, but different flight plans. It was observed that the performance of MACS degraded for air traffic scenarios containing more than 200 aircraft (37.5 KB/s nominal throughput). However, ATG performed adequately under all tested air traffic loads up to 1200 aircraft (225. KB/s nominal throughput). The tests show that MACS exhibits better latency performance with smaller aircraft loads when compared to ATG. The tests also show that the TestBed infrastructure successfully transmits 1200 aircraft without significant degradation of its performance. From the latency trends for both MACS and ATG, it is clear that as aircraft load increases, the latency in the system increases as well as its standard deviation. Likewise, the trends for the update data rate for both MACS and ATG show that as the aircraft load increases, so does the standard deviation and mean of the update rates which can be attributed to the performance of MACS and ATG applications. The analysis of the results of this study have proven that the overall system performance is dependent on the individual performance of each system component that is connected to TestBed, which subsequently propagates into the system. All TestBed characterization tests were conducted in SimLabs at NASA Ames Research Center in November 2019. This study addresses the need for a baseline TestBed characterization, and the results will serve as a reference for more complex simulation systems.

Air Traffic Management simulations↗
DOE OSTI2020

Medium amplitude parallel superposition (MAPS) rheology. Part 2: Experimental protocols and data analysis

An experimental protocol is developed to directly measure the new material functions revealed by medium amplitude parallel superposition (MAPS) rheology. This protocol measures the medium amplitude response of a material to a simple shear deformation composed of three sine waves at different frequencies, revealing a rich dataset consisting of up to 19 measurements of the third-order complex modulus at distinct three-frequency coordinates. We discuss how the choice of input frequencies influences the features of the MAPS domain studied by the experiment. A polynomial interpolation method for reducing the bias of measured values from spectral leakage and reducing variance due to noise is discussed, including a derivation of the optimal range of amplitudes for the input signal. This leads to the conclusion that conducting the experiment in a stress-controlled fashion possesses a distinct advantage to the strain-controlled mode. The experimental protocol is demonstrated through measurements of the MAPS response of a model complex fluid: a surfactant solution of wormlike micelles. The resulting dataset is indeed large and feature-rich, while still acquired in a time comparable to similar medium amplitude oscillatory shear (MAOS) experiments. We demonstrate that the data represent measurements of an intrinsic material function by studying its internal consistency, compatibility with low-frequency predictions for Coleman–Noll simple fluids, and agreement with data obtained via MAOS amplitude sweeps. Finally, the data are compared to predictions from the corotational Maxwell model to demonstrate the power of MAPS rheology in determining whether a constitutive model is consistent with a material’s time-dependent response.

Lennon, Kyle R. (ORCID:0000000212515461)↗
DOE OSTI2011

Studies of future readout links for the CMS experiment

The Compact Muon Solenoid (CMS) experiment has developed an electrical implementation of the S-LINK64 extension (Simple Link Interface 64 bit) operating at 400 MB/s in order to read out the detector. This paper studies a possible replacement of the existing S-LINK64 implementation by an optical link, based on 10 Gigabit Ethernet in order to fulfil larger throughput, replace aging hardware and simplify an architecture. A prototype transmitter unit has been developed based on the FPGA Altera PCI Express Development Kit with a custom firmware. A standard PC has been acted as receiving unit. The data transfer has been implemented on a stack of protocols: RDP over IP over Ethernet. This allows receiving the data by standard hardware components like PCs or network switches and NICs. The first test proved that basic exchange of the packets between transmitter and receiving unit works. The paper summarizes the status of these studies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Fine-scale evaluation of two standard 16S rRNA gene amplicon primer pairs for analysis of total prokaryotes and archaeal nitrifiers in differently managed soils

The advance of high-throughput molecular biology tools allows in-depth profiling of microbial communities in soils, which possess a high diversity of prokaryotic microorganisms. Amplicon-based sequencing of 16S rRNA genes is the most common approach to studying the richness and composition of soil prokaryotes. To reliably detect different taxonomic lineages of microorganisms in a single soil sample, an adequate pipeline including DNA isolation, primer selection, PCR amplification, library preparation, DNA sequencing, and bioinformatic post-processing is required. Besides DNA sequencing quality and depth, the selection of PCR primers and PCR amplification reactions arguably have the largest influence on the results. This study tested the performance and potential bias of two primer pairs, i.e., 515F (Parada)-806R (Apprill) and 515F (Parada)-926R (Quince) in the standard pipelines of 16S rRNA gene Illumina amplicon sequencing protocol developed by the Earth Microbiome Project (EMP), against shotgun metagenome-based 16S rRNA gene reads. The evaluation was conducted using five differently managed soils. We observed a higher richness of soil total prokaryotes by using reverse primer 806R compared to 926R, contradicting to in silico evaluation results. Both primer pairs revealed various degrees of taxon-specific bias compared to metagenome-derived 16S rRNA gene reads. Nonetheless, we found consistent patterns of microbial community variation associated with different land uses, irrespective of primers used. Total microbial communities, as well as ammonia oxidizing archaea (AOA), the predominant ammonia oxidizers in these soils, shifted along with increased soil pH due to agricultural management. In the unmanaged low pH plot abundance of AOA was dominated by the acid-tolerant NS-Gamma clade, whereas limed agricultural plots were dominated by neutral-alkaliphilic NS-Delta/NS-Alpha clades. This study stresses how primer selection influences community composition and highlights the importance of primer selection for comparative and integrative studies, and that conclusions must be drawn with caution if data from different sequencing pipelines are to be compared.

16S rRNA gene amplicon Illumina sequencing↗
DOE OSTI2020

Consensus Weighting of a Multi-Agent System for Load Shedding

An agent-based scheme is proposed for distributed underfrequency load shedding (UFLS). The key concept is a consensus weighting protocol (CWP) for agents to reach an agreement. Unlike the well adopted average-consensus protocol (ACP), the proposed CWP enables each agent to converge to its weighted portion of the sum of all initial values. Thus, the proposed CWP is more suitable for the UFLS application, as it allows load buses with a higher level of loading to shed more, rather than reducing by the same average value over all load buses as required by the ACP. Proof of convergence for the proposed CWP is derived and presented in this paper, together with the constraints. For implementation of the multi-agent system (MAS), the monitoring, estimation, and distribution steps are developed. Two study cases and the simulation results are provided to validate the performance of the proposed agent-based UFLS scheme.

Xie, Jing↗
DOE OSTI2019

Rapid kVp switching dual-energy CT in the assessment of urolithiasis in patients with large body habitus: preliminary observations on image quality and stone characterization

Purpose: The purpose of this study was to investigate the image quality (IQ) considerations of rapid kVp switching dual-energy CT (rsDECT) in the assessment of urolithiasis in patients with large body habitus and to evaluate whether it allows stone characterization. Materials and methods: In this IRB-approved, HIPAA compliant retrospective study, 93 consecutive patients (M/F = 72/21, mean age 56.9 years, range 23–83 years) with large body habitus (> 90 kg/198 lbs) who underwent dual-energy (DE) stone protocol CT on a rapid kVp switching DECT scanner between January 2013 and December 2016 were included. Scan acquisition protocol included an initial unenhanced single-energy CT (SECT) scan of KUB followed by targeted DECT in the region of stones. Two readers evaluated both CT data sets (axial 5 mm 120 kVp/140 kVp QC/70 keV monoenergetic, material density water/iodine images and coronal/sagittal 3 mm images) for the assessment of image quality (Scores: 1–4) and characterization of stone composition (reference standard: crystallography). Results: One hundred and five CT examinations were performed in 93 patients (mean body weight 105.12 ± 13.53 kg, range 91–154 kg), and a total of 321 urinary tract calculi (mean size-4.8 ± 3.2 mm, range 1.2–22 mm) were detected. Both SECT and targeted monoenergetic images were of acceptable image quality (mean IQ: 3.77 and 3.83, kappa 0.79 and 0.87 respectively). Material density water and iodine images had lower IQ scores (mean IQ: 2.97 and 3.09 respectively) with image quality deterioration due to severe photon starvation/streak artifacts in 20% (21/105) and 17% (18/105) scans, respectively. Characterization of stone composition into uric acid/non-uric acid stones was achieved in 93.14% (299/321) of calculi (mean size: 4.99 ± 3.3 mm, range 1.2–22 mm), while 7% (22/321) stones could not be characterized (mean size 3.03 ± 1.16 mm, range 1.6–6.4 mm) (p < 0.001). Most common reason for non-characterization was image quality deterioration of the material density iodine images due to severe photon starvation artifacts. On multivariate regression, stone size and patient weight were predictors of stone composition determination on DECT (p < 0.05). The transverse diameter had a weak negative correlation with stone composition determination, but it was not statistically significant. Stone characterization into uric acid vs. non-uric acid stones was accurate in 95% (n = 38/40) of stones in comparison with crystallography. Conclusion: In patients with large body habitus, rsDECT allowed characterization of most calculi (93%) despite image quality deterioration due to photon starvation/streak artifacts in up to 20% of material density images. Stone size and patient weight were predictors of stone composition determination on DECT, and small calculi in very large patients may not be characterized.

62 RADIOLOGY AND NUCLEAR MEDICINE↗