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DOE OSTI2021

Traveling Wave Relays for Distribution Feeder Protection with High Penetrations of Distributed Energy Resources: Preprint

Increased penetration of power electronics interfaced Distributed Energy Resources (DER) like PV, electric vehicle and battery storage in the distribution system (both in numbers and sizes) may cause bi-directional power flows under normal operation. In addition, they contribute low fault current under short circuit conditions. These two changes can impact the proper operation of legacy protection systems. This can add additional challenges during weak grid and islanded operation. In this research, traveling wave (high frequency) signature based protection scheme is proposed for future distribution systems. Simulations are performed under different transient scenarios to provide insight into the high frequency signatures to show the traveling wave behavior. Finally, this paper discusses the importance of sensing and digital processing requirements for traveling-wave protection in distribution system.

41 EE - Solar Energy Technologies Office (EE-4S)↗

DOE OSTI2021

Traveling Wave Relays for Distribution Feeder Protection with High Penetrations of Distributed Energy Resources

41 EE - Solar Energy Technologies Office (EE-4S)↗

DOE OSTI2016

MO-G-201-04: Knowledge-Based Planning for Single-Isocenter Stereotactic Radiosurgery to Multiple Brain Metastases

Purpose: Single-isocenter, linac-based SRS for multiple brain metastases (multi-mets) can deliver highly conformal radiation doses and reduce overall patient treatment time compared to other therapy techniques. This study aims to quantify the dosimetric benefits of knowledge-based planning (KBP) for multi-met treatments. Methods: Using a previously-published KBP methodology (an artificial neural network (ANN) trained on single-target linac-based SRS plans), 3D dose distribution predictions for multi-met patients were obtained by treating each brain lesion as a solitary target and subsequently combining individual predictions into a single distribution using a dose-weighted geometric averaging to obtain the best results in the inter-target space. 17 previously-treated multi-met plans, with target numbers ranging from N=2–5, were used to validate the ANN predictions and subsequent KBP auto-planning routine. The fully-deliverable KBP plans were developed by converting dose distribution predictions into patient-specific optimization objectives while maintaining identical target normalizations (typically PTV V100%=D98%). Plan quality improvements were quantified by the difference between SRS quality metrics (QMs): δdQM=QM(clinical)-QM(KBP). QMs of interest were: gradient measure (GM), conformity index (CI), brain V10 and V5, brainstem D0.1cc and heterogeneity index (HI). Finally, overall plan quality was judged via blinded plan comparison by SRS-specializing physicians. Results: Two clinical plans were found to be significant outliers wherein plan quality was dramatically worse than KBP. Despite indicating KBP superiority, these were removed from the QM analysis to prevent skewing the results. In the remaining cases, clinical and KBP QMs were nearly identical with modest improvements in the KBP sample: δGM=0.12±0.56mm, δCI=−0.01±0.04, Brain δV10=0.8±2.6cc, brain δV5=6.3 ±10.7cc, brainstem δD0.1cc=0.06±1.19Gy and δHI= −0.04±0.05. Ultimately, 13/17 KBP plans were deemed superior to the manual plans in blinded physician review. Conclusion: The results demonstrate that KBP-driven automated planning in linac-based single-isocenter treatments for multiple brain metastases is indistinguishable from, or even better than, traditional manual planning. J. Hattangadi: Research Grant; Varian Medical Systems; K.L. Moore: Research Grant: Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2019

Effect of choosing the Q{sub α}-values and daughter density distributions on the magic numbers predicted by α decays

We investigated the effects of choosing the α-decay energy (Q{sub α}) and particular density distributions of the daughter nuclei on predicting unknown magic numbers, or confirming some of them. The Q{sub α} values were calculated using three models, namely the finite-range droplet model (FRDM), the Weizsäcker–Skyrme (WS4) mass model, and a recent fitting formula. The α-decay half-lives (T{sub α}) of superheavy nuclei of Z = 118–124 have been calculated within the generalized density-dependent cluster model. The double-folding α+core potential was determined based on the M3Y-Reid nucleon–nucleon interaction. We have used the two-parameter Fermi distribution to represent the nuclear density, with four sets of parameters that were determined based on electron scattering data and different microscopic calculations. Upon investigating the relative stability of the mentioned superheavy isotopic chains, we found that the Q{sub α}-values deduced from FRDM and WS4 models predict different neutron magic numbers. The examined fitting formula failed to predict any magic number larger than N = 162. Under normalization to the proton and neutron (N) numbers, the different choices of the density distributions showed almost no effect on the general behavior of T{sub α} with N, but changed its values up to one order of magnitude. Even though the maxima and minima of T{sub α} clearly follow the characteristic minima and maxima of Q{sub α}, respectively, the results showed that precise density distribution and deformations, in addition to a correct preformation probability, are necessarily required for estimating an accurate value of the half-life.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS1990

A semiempirical method for obtaining fuselage normal areas from fuselage Mach sliced areas

An aircraft designed to meet low sonic boom or shaped ground overpressure signature requirements has a volume and lift equivalent area distribution which is in close agreement with the equivalent areas of a desired theoretical curve. Final-stage design modifications of the aircraft's geometry to meet this requirement are usually made through adjustments to the fuselage normal cross-section areas that are derived from the corresponding fuselage equivalent areas by iterative methods. The time required to obtain a good agreement between the desired low-boom area distribution and the conceptual aircraft total area distribution can be reduced by using a semi-empirical method which eliminates much of the final trial-and-error iteration previously employed. Fuselages from conceptual aircraft designed to generate low sonic boom ground overpressures at cruise Mach numbers of 2.0 and 3.0 were used as examples to examine the method's capabilities and limitations. Results indicated that the method has merit as a design tool consistent with other linear theory methods.

Mack, Robert J.↗

NASA NTRS2000

Numerical Calculation of the Drag Force Acting on a Solid Particle Pushed by a Solid/Liquid Interface

The distribution of insoluble particles in a metal casting depends primarily on the interaction of the particles with the solid/liquid interface (SLI) during the solidification process. The balance of the forces acting on the particle essentially determines whether a particle will be engulfed or pushed by the SLI. An important component of this force balance is the drag force generated by the particle motion in front of the SLI. Previously developed mathematical models for particle/SLI interaction made use of steady-state solutions of this force provided by the lubrication theory. However, our numerical model based on the SLI tracking approach shows that the steady-state approach is inappropriate to model the interaction process and that at steady-state the theoretical solution underestimates the drag force. It was found that regression analysis of steady-state numerical solutions for cylindrical particles moving normal to a flat SLI gives a relationship of the form: Abstract The distribution of insoluble particles in a metal casting depends primarily on the interaction of the particles with the solid/liquid interface (SLI) during the solidification process. The balance of the forces acting on the particle essentially determines whether a particle will be engulfed or pushed by the SLI. An important component of this force balance is the drag force generated by the particle motion in front of the SLI. Previously developed mathematical models for particle/SLI interaction made use of steady-state solutions of this force provided by the lubrication theory. However, our numerical model based on the SLI tracking approach shows that the steady-state approach is inappropriate to model the interaction process and that at steady-state the theoretical solution underestimates the drag force. It was found that regression analysis of steady-state numerical solutions for cylindrical particles moving normal to a flat SLI gives a relationship of the form: F(sub D, sup num) =sqoare root of 3(pi)(eta)V(sub p)(R(sub p)/d)(sup 10(gamma)/3). This is to compared to the solution provided by the lubrication theory: F(sub D), sup theor) = 3 square root of 2(pi)(eta)V(sub p)(R(sub p)/d)(sub 3/2), where F(sub D) is the drag force, eta is the dynamic viscosity of the fluid, V(sub p) is the particle velocity, R(sub p) is the particle radius, gamma is Euler's constant (gamma approx. = 0.577), and d is the width of the gap between the particle and the SLI. The domain on which the equations proposed by the lubrication theory are relevant is clearly identified in the paper. The numerical model was then validated against the classical lubrication theory within the domain of its validity.

Catalina, Adrian V.↗

DOE OSTI2020

Robust Matrix Completion State Estimation in Distribution Systems

Due to the insufficient measurements in the distribution system state estimation (DSSE), full observability and redundant measurements are difficult to achieve without using the pseudo measurements. The matrix completion state estimation (MCSE) combines the matrix completion and power system model to estimate voltage by exploring the low-rank characteristics of the matrix. This paper proposes a robust matrix completion state estimation (RMCSE) to estimate the voltage in a distribution system under a low-observability condition. Tradition state estimation weighted least squares (WLS) method requires full observability to calculate the states and needs redundant measurements to proceed a bad data detection. The proposed method improves the robustness of the MCSE to bad data by minimizing the rank of the matrix and measurements residual with different weights. It can estimate the system state in a low-observability system and has robust estimates without the bad data detection process in the face of multiple bad data. The method is numerically evaluated on the IEEE 33-node radial distribution system. The estimation performance and robustness of RMCSE are compared with the WLS with the largest normalized residual bad data identification (WLS-LNR), and the MCSE.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2019

Robust Matrix Completion State Estimation in Distribution Systems: Preprint

24 POWER TRANSMISSION AND DISTRIBUTION↗

NASA NTRS2000

Radiative Properties of Cirrus Clouds in the Infrared (8-13 microns) Spectral Region

Atmospheric radiation in the infrared (IR) 8-13 microns spectral region contains a wealth of information that is very useful for the retrieval of ice cloud properties from aircraft or space-borne measurements. To provide the scattering and absorption properties of nonspherical ice crystals that are fundamental to the IR retrieval implementation, we use the finite-difference time domain (FDTD) method to solve for the extinction efficiency, single-scattering albedo, and the asymmetry parameter of the phase function for ice crystals smaller than 40 microns. For particles larger than this size, the improved geometric optics method (IGOM) can be employed to calculate the asymmetry parameter with an acceptable accuracy, provided that we properly account for the inhomogeneity of the refracted wave due to strong absorption inside the ice particle. A combination of the results computed from the two methods provides the asymmetry parameter for the entire practical range of particle sizes between 1 micron and 10000 microns over wavelengths ranging from 8 microns to 13 microns. For the extinction and absorption efficiency calculations, several methods including the IGOM, Mie solution for equivalent spheres (MSFES), and the anomalous diffraction theory (ADT) can lead to a substantial discontinuity in comparison with the FDTD solutions for particle sizes on the order of 40 microns. To overcome this difficulty, we have developed a novel approach called the stretched scattering potential method (SSPM). For the IR 8-13 microns spectral region, we show that SSPM is a more accurate approximation than ADT, MSFES, and IGOM. The SSPM solution can be further refined numerically. Through a combination of the FDTD and SSPM, we have computed the extinction and absorption efficiency for hexagonal ice crystals with sizes ranging from 1 to 10000 microns at 12 wavelengths between 8 and 13 microns Calculations of the cirrus bulk scattering and absorption properties are performed for 30 size distributions obtained from various field campaigns for midlatitude and tropical cirrus cloud systems. Parameterization of these bulk scattering properties is carried out by using second-order polynomial functions for the extinction efficiency and the single-scattering albedo and the power law expression for the asymmetry parameter. We note that the volume-normalized extinction coefficient can be separated into two parts: one is inversely proportional to effective size and is independent of wavelength, and the other is the wavelength-dependent effective extinction efficiency. Unlike conventional parameterization efforts, the present parameterization scheme is more accurate because only the latter part of the volume-normalized extinction coefficient is approximated in terms of an analytical expression. After averaging over size distribution, the single-scattering albedo is shown to decrease with an increase in effective size for wavelengths shorter than 10.0 microns whereas the opposite behavior is observed for longer wavelengths. The variation of the asymmetry parameter as a function of effective size is substantial when the effective size is smaller than 50 microns. For effective sizes larger than 100 microns, the asymmetry parameter approaches its asymptotic value. The results derived in this study can be useful to remote sensing applications involving IR window bands under cirrus cloud conditions.

Yang, Ping↗

DOE OSTI2017

Numerical Simulations of Particle Acceleration at Interplanetary Quasi-perpendicular Shocks

Using test particle simulations we study particle acceleration at highly perpendicular (θ{sub Bn}⩾75{sup ∘}) shocks under conditions of modeling magnetic turbulence. We adopt a backward-in-time method to solve the Newton–Lorentz equation using the observed shock parameters for quasi-perpendicular interplanetary shocks, and compare the simulation results with ACE/EPAM observations to obtain the injection energy and timescale of particle acceleration. With our modeling and observations, we find that a large upstream speed is responsible for efficient particle acceleration. Our results also show that the quasi-perpendicular shocks are capable of accelerating thermal particles to high energies of the order of MeV for both kappa and Maxwellian upstream distributions, which may originate from the fact that in our model, the local background magnetic field has a component parallel to the shock normal.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1984

A model function for ocean radar cross sections at 14.6 GHz

The relationship between the ocean's normalized radar cross section (NRCS) at 14.6 GHz and the surface wind vector is derived using the 3 months of Seasat microwave scatterometer (SASS) measurements. The derivation is based on the statistics of the SASS observations, and no in situ measurements are required, other than a mean global wind speed, which comes from climatology. The frequency distribution of the global wind vectors observed by SASS is assumed to be a bivariate normal probability function. A NRCS model function is found that maps the assumed wind vector statistics into the observed SASS NRCS statistics. This function is compared with a NRCS model coming from the Joint Air Sea Interaction Experiment (JASIN) and with aircraft scatterometer measurements. The results indicate that the statistically derived NRCS model is an improvement over the JASIN model, which was based on a limited number of in situ anemometer measurements.

Wentz, F. J.↗

DOE OSTI2014

SU-E-J-56: Dosimetric Impact of Patient Roll Variability in Peripheral-Lung SBRT

Purpose: Positional variation about the patient longitudinal axis may introduce deleterious effects to clinical treatment plans, the effects of which are exacerbated by hypo-fractionated treatment regimens. Our goal is to evaluate the dosimetric impact of rotational setup error in stereotactic body radiation therapy (SBRT) for peripherally-located lung lesions. Methods: Six patients who had been treated for peripheral lung lesions using varying SBRT techniques were analyzed. Each patient's planning CT was processed using custom in-house software to simulate 1, 3, and 5 degree roll in both directions about their longitudinal axis. The original plan was fused and re-calculated. Agreement between planned and error-simulated dose distributions was quantified using 3%, 3mm criteria for the 3-dimensional gamma metric, and changes in target coverage and adjacent normal anatomy were also quantified. Results: Increased rotational setup error resulted in reduced target coverage, with changes in equivalent uniform dose ranging from −1.24% to −6.11% for simulated roll greater than or equal to 3 degrees, increasing with magnitude of error and skewed for roll directed toward the involved side. Changes to normal tissue metrics are linearly related to simulated roll, with rib D(1cc) changes ranging from −4.23% to 3.27% relative to the original treatment plan. Error-simulated dose distributions demonstrate agreement by the gamma metric in the planned target of 72.56%, 81.02%, and 99.52% for 5, 3, and 1 degree simulated roll scenarios, respectively. Corresponding agreement for the regional dose in excess of 50% of the maximum were 65.71%,70.77%, and 97.88%. Conclusion: This study suggests that the ability to detect and compensate for rotational positioning variations beyond a threshold level may improve care for patients with peripherally-located lesions beyond that which may be accomplished using only translational axes. Positional error of one degree of roll had little influence, though three or more degrees of error introduced significant discrepancy.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2014

Rare earth element components in atmospheric particulates in the Bayan Obo mine region

The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM{sub 10}) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m{sup 3}, and those for PM{sub 10} were 42.8 and 68.9 ng/m{sup 3}, in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM{sub 10} and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM{sub 10} were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La{sub N}/Yb{sub N}, La{sub N}/Sm{sub N}, Gd{sub N}/Yb{sub N}). - Highlights: • TSP and PM{sub 10} samples were collected to analyze the levels and distributions of REE. • Enrichment factors indicated that REE enrichment was caused by anthropogenic sources. • The distribution of REEs showed a strong gradient in the prevailing wind direction. • Obvious fractionation between LREEs and HREEs is observed in atmospheric particulates.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1992

Generic grain size distribution for liquid phase sintering

In order to develop an empirical model to represent a generic grain size distribution for liquid phase sintering, experimental data and theoretical models are analyzed using the plot of standard normal vs normalized size. From the experimental 3D grain size plot, the most representative line is deduced. The line best fits the Lifshitz-Slyozov encounter modified model except for the small size ranges of the lower 15 percent of the distribution. It is shown that grain coalescence might be a cause for this departure from theory.

German, R. M.↗

DOE OSTI2017

Measurement of Top Quark Polarization in $t\bar{t}$ Lepton + Jets Final States at D0

We present a measurement of top quark polarization in $t\bar{t}$ pair production in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using data corresponding to 9.7 fb$^{-1}$ of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the $t\bar{t}$ production plane. This is the first measurement of top quark polarization at Tevatron using lepton+jet final states and the first measurement of the transverse polarization in $t\bar{t}$ production. The observed distributions are consistent with standard model predictions of nearly no polarization.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Postoperative radiotherapy following mastectomy for patients with left-sided breast cancer: A comparative dosimetric study

The purposes of this article were to compare the biophysical dosimetry for postmastectomy left-sided breast cancer using 4 different radiotherapy (RT) techniques. In total, 30 patients with left-sided breast cancer were randomly selected for this treatment planning study. They were planned using 4 RT techniques, including the following: (1) 3-dimensional conventional tangential fields (TFs), (2) tangential intensity-modulated therapy (T-IMRT), (3) 4 fields IMRT (4F-IMRT), and (4) single arc volumetric-modulated arc therapy (S-VMAT). The planning target volume (PTV) dose was prescribed 50 Gy, the comparison of target dose distribution, conformity index, homogeneity index, dose to organs at risk (OARs), tumor control probability (TCP), normal tissue complication probability (NTCP), and number of monitor units (MUs) between 4 plans were investigated for their biophysical dosimetric difference. The target conformity and homogeneity of S-VMAT were better than the other 3 kinds of plans, but increased the volume of OARs receiving low dose (V{sub 5}). TCP of PTV and NTCP of the left lung showed no statistically significant difference in 4 plans. 4F-IMRT plan was superior in terms of target coverage and protection of OARs and demonstrated significant advantages in decreasing the NTCP of heart by 0.07, 0.03, and 0.05 compared with TFs, T-IMRT, and S-VMAT plan. Compared with other 3 plans, TFs reduced the average number of MUs. Of the 4 techniques studied, this analysis supports 4F-IMRT as the most appropriate balance of target coverage and normal tissue sparing.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2013

GALAXY HALO TRUNCATION AND GIANT ARC SURFACE BRIGHTNESS RECONSTRUCTION IN THE CLUSTER MACSJ1206.2-0847

In this work, we analyze the mass distribution of MACSJ1206.2-0847, particularly focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has a significant amount of intracluster light that is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at z = 1.033 into a giant arc and its counterimage. The multiple image positions and the surface brightness (SFB) distribution of the arc, which is bent around several cluster members, are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a Navarro-Frenk-White profile and the galaxy halos with two parameters for the mass normalization and the extent of a reference halo assuming scalings with their observed near-infrared light. We match the multiple image positions at an rms level of 0.''85 and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii-a scale in between those accessible to dynamical and field strong-lensing mass estimates on the one hand and galaxy-galaxy weak-lensing results on the other hand. The velocity dispersion and halo size of a galaxy with m{sub 160W,AB} = 19.2 and M{sub B,Vega} = -20.7 are {sigma} = 150 km s{sup -1} and r Almost-Equal-To 26 {+-} 6 kpc, respectively, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source, which is smaller by a factor of {approx}5.8 in area, demonstrating the increase in morphological information due to lensing. We conclude that this galaxy likely has star-forming spiral arms with a red (older) central component.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1980

Radar altimeter mean return wave forms from near-normal-incidence ocean surface scattering

For a nearly Gaussian transmitted pulse shape scattered from a nearly Gaussian distributed sea surface, a small argument series expansion of one term lead to a several term power series expression for the mean return waveform. Specific expressions are given for the first four terms. These results, which require less computer time than numerical convolution, are useful for data analysis from current or past radar altimeters and for design studies of future systems. Several representative results are presented for an idealized Seasat-1 radar altimeter.

Hayne, G. S.↗