A learning-based time-efficient framework for building energy performance evaluation
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Bhattacharya, Saptarshi↗
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Deep inspiration breath-hold technique for left-sided breast cancer: An analysis of predictors for organ-at-risk sparing
To identify anatomic and treatment characteristics that correlate with organ-at-risk (OAR) sparing with deep inspiration breath-hold (DIBH) technique to guide patient selection for this technique. Anatomic and treatment characteristics and radiation doses to OARs were compared between free-breathing and DIBH plans. Linear regression analysis was used to identify factors independently predicting for cardiac sparing. We identified 64 patients: 44 with intact breast and 20 postmastectomy. For changes measured directly on treatment planning scans, DIBH plans decreased heart-chest wall length (6.5 vs 5.0 cm, p < 0.001), and increased lung volume (1074.4 vs 1881.3 cm{sup 3}, p < 0.001), and for changes measured after fields are set, they decreased maximum heart depth (1.1 vs 0.3 cm, p < 0.001) and heart volume in field (HVIF) (9.1 vs 0.9 cm{sup 3}, p < 0.001). DIBH reduced the mean heart dose (3.4 vs 1.8 Gy, p < 0.001) and lung V{sub 20} (19.6% vs 15.3%, p < 0.001). Regression analysis found that only change in HVIF independently predicted for cardiac sparing. We identified patients in the bottom quartile of the dosimetric benefits seen with DIBH and categorized the cause of this “minimal benefit.” Overall, 29% of patients satisfied these criteria for minimal benefit with DIBH and the most common cause was favorable baseline anatomy. Only the reduction in HVIF predicted for reductions in mean heart dose; no specific anatomic surrogate for the dosimetric benefits of DIBH technique could be identified. Most patients have significant dosimetric benefit with DIBH, and this technique should be planned and evaluated for all patients receiving left-sided breast/chest wall radiation.
61 RADIATION PROTECTION AND DOSIMETRY↗
Effect of H + Exchange and Surface Impurities on Bulk and Interfacial Electrochemistry of Garnet Solid Electrolytes
Contact loss and current constriction pose significant challenges at the Li metal interface of solid-state batteries. For garnet-structured Li 7 La 3 Zr 2 O 12 (LLZO), these effects are amplified by Li + /H + exchange and surface contamination reactions, which lead to conductivity losses and poor Li wetting. In this study, we utilize a variety of surface treatment processes across 37 cells to selectively induce proton exchange and contamination reactions in LLZO. The resulting bulk and surface chemistry is systematically characterized and correlated to changes in electrochemical properties. Additionally, we combine impedance analysis and finite element method modeling to deconvolute sources of impedance contributions at the Li metal interface. Specifically, we show that constriction impedance at the Li metal interface arises not solely from voids, but also from ionically-resistive surface contaminants. Further, these findings emphasize the connection between ionic conductivity and constriction, demonstrating that micron-scale ionically-resistive components increase constriction even with identical contact geometries. Finally, we leverage our comprehensive dataset to highlight unstable overpotential growth as a failure mechanism, additionally showing that the phase of a cell’s impedance is a sensitive indicator for the onset of interfacial instability. Overall, this study clarifies the impacts of proton exchange and surface contamination on electrochemical properties at the Li|solid electrolyte interface and elucidates insights that are generalizable to other solid-state battery systems.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Integrated Two-Stage Alkaline-Oxidative Pretreatment of Hybrid Poplar. Part 1: Impact of Alkaline Pre-Extraction Conditions on Process Performance and Lignin Properties
We previously demonstrated that a two-stage pretreatment comprising of an alkaline pre-extraction followed by a Cu-catalyzed alkaline–oxidative treatment is effective at pretreating hardwoods under relatively mild reaction conditions. In this work, we focus on characterizing how biomass source and reaction conditions used during the alkaline pre-extraction impact the subsequent processing stages as well as lignin yields and properties. Specifically, three hybrid poplars were subjected to the first stage alkaline pre-extraction under various conditions including differences in time (15–300 min), temperature (95–155 °C), and alkali loadings (50–200 mg NaOH/g biomass), and the impact on total mass solubilization, lignin recovery, and lignin purity was determined. Empirical correlations were developed between reaction conditions and mass solubilization and lignin recovery during the pre-extraction stage. For select conditions, lignin properties were assessed and include β-O-4 content determined by 13C NMR, molecular mass distributions as determined by gel permeation chromatography, and susceptibility to depolymerization to aromatic monomers using thioacidolysis and formic acid catalyzed depolymerization. We found alkaline pre-extraction performed at higher temperatures generated lignins exhibiting lower contamination by polysaccharides, lower aromatic monomer yields from depolymerization, lower molar masses, and lower β-O-4 contents relative to the lower temperature pre-extractions. Lastly, the pre-extracted biomass from select conditions was assessed for its response to the subsequent Cu-catalyzed alkaline–oxidative treatment and enzymatic hydrolysis. It was demonstrated that minor differences in delignification during pre-extraction have quantifiable impacts on the subsequent efficacy of the second stage of pretreatment and enzymatic hydrolysis with improved lignin removal during the first pre-extraction stage resulting in improved hydrolysis yields.
09 BIOMASS FUELS↗
Advances in QCD sum-rule calculations
We review the recent progress in the applications of QCD sum rules to hadron properties with the emphasis on the following selected problems: (i) development of new algorithms for the extraction of ground-state parameters from two-point correlators; (ii) form factors at large momentum transfers from three-point vacuum correlation functions: (iii) properties of exotic tetraquark hadrons from correlation functions of four-quark currents.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
An analysis of carrier dynamics in methylammonium lead triiodide perovskite solar cells using cross correlation noise spectroscopy
Using cross correlation current noise spectroscopy, we have investigated carrier dynamics in methylammonium lead triiodide solar cells. This method provides space selectivity for devices with a planar multi-layered structure, effectively amplifying current noise contributions coming from the most resistive element of the stack. In the studied solar cells, we observe near full-scale shot noise, indicating the dominance of noise generation by a single source, likely the interface between the perovskite and the spiro-organic 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene hole-transport layer. In this paper, we argue that the strong 1/f noise term has contributions from both the perovskite layer and interfaces. It displays a non-ideal dependence on photocurrent, S $\propto$ I 1.4 (instead of usual S $\propto$ I 2 ), which is likely due to current-induced halide migration. Finally, we observe generation–recombination noise. We argue that this contribution is due to bimolecular recombination in the perovskite bulk absorption layer. Extrapolating our results, we estimate that at standard 1 sun illumination, the electron–hole recombination time is 5 microseconds.
14 SOLAR ENERGY↗
Far-infrared and accretion luminosities of the present-day active galactic nuclei
We investigate the relation between star formation (SF) and black hole accretion luminosities, using a sample of 492 type-2 active galactic nuclei (AGNs) at z<0.22, which are detected in the far-infrared (FIR) surveys with AKARI and Herschel. We adopt FIR luminosities at 90 and 100 μm as SF luminosities, assuming the proposed linear proportionality of star formation rate with FIR luminosities. By estimating AGN luminosities from [O iii]λ5007 and [O i]λ6300 emission lines, we find a positive linear trend between FIR and AGN luminosities over a wide dynamical range. This result appears to be inconsistent with the recent reports that low-luminosity AGNs show essentially no correlation between FIR and X-ray luminosities, while the discrepancy is likely due to the Malmquist and sample selection biases. By analyzing the spectral energy distribution, we find that pure-AGN candidates, of which FIR radiation is thought to be AGN-dominated, show significantly low-SF activities. These AGNs hosted by low-SF galaxies are rare in our sample (∼1%). However, the low fraction of low-SF AGNs is possibly due to observational limitations since the recent FIR surveys are insufficient to examine the population of high-luminosity AGNs hosted by low-SF galaxies.
79 ASTRONOMY AND ASTROPHYSICS↗
Generalized quasiharmonic approximation via space group irreducible derivatives
The quasiharmonic approximation (QHA) is the simplest nontrivial approximation for interacting phonons under constant pressure, bringing the effects of anharmonicity into temperature-dependent observables. Nonetheless, the QHA is often implemented with additional approximations due to the complexity of computing phonons under arbitrary strains, and the generalized QHA, which employs constant stress boundary conditions, has not been completely developed. In this work we formulate the generalized QHA, providing a practical algorithm for computing the strain state and other observables as a function of temperature and true stress. We circumvent the complexity of computing phonons under arbitrary strains by employing irreducible second-order displacement derivatives of the Born-Oppenheimer potential and their strain dependence, which are efficiently and precisely computed using the lone irreducible derivative approach. We formulate two complementary strain parametrizations: a discretized strain grid interpolation and a Taylor series expansion in symmetrized strain. We illustrate our approach by evaluating the temperature and pressure dependence of select elastic constants and the thermal expansion in thoria (ThO 2 ) using density functional theory with three exchange-correlation functionals. The QHA results are compared to our measurements of the elastic constant tensor using time-domain Brillouin scattering and inelastic neutron scattering. Our irreducible derivative approach simplifies the implementation of the generalized QHA, which will facilitate reproducible, data-driven applications.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
SU-E-T-422: Fast Analytical Beamlet Optimization for Volumetric Intensity-Modulated Arc Therapy
Purpose: To implement a fast optimization algorithm on CPU/GPU heterogeneous computing platform and to obtain an optimal fluence for a given target dose distribution from the pre-calculated beamlets in an analytical approach. Methods: The 2D target dose distribution was modeled as an n-dimensional vector and estimated by a linear combination of independent basis vectors. The basis set was composed of the pre-calculated beamlet dose distributions at every 6 degrees of gantry angle and the cost function was set as the magnitude square of the vector difference between the target and the estimated dose distribution. The optimal weighting of the basis, which corresponds to the optimal fluence, was obtained analytically by the least square method. Those basis vectors with a positive weighting were selected for entering into the next level of optimization. Totally, 7 levels of optimization were implemented in the study.Ten head-and-neck and ten prostate carcinoma cases were selected for the study and mapped to a round water phantom with a diameter of 20cm. The Matlab computation was performed in a heterogeneous programming environment with Intel i7 CPU and NVIDIA Geforce 840M GPU. Results: In all selected cases, the estimated dose distribution was in a good agreement with the given target dose distribution and their correlation coefficients were found to be in the range of 0.9992 to 0.9997. Their root-mean-square error was monotonically decreasing and converging after 7 cycles of optimization. The computation took only about 10 seconds and the optimal fluence maps at each gantry angle throughout an arc were quickly obtained. Conclusion: An analytical approach is derived for finding the optimal fluence for a given target dose distribution and a fast optimization algorithm implemented on the CPU/GPU heterogeneous computing environment greatly reduces the optimization time.
60 APPLIED LIFE SCIENCES↗
Diagnostic device for monitoring the technical condition of mechanical assemblies
An automatic diagnostic device for monitoring the condition of tractor transmission gears is described. The structural noise spectrum of the gearshift box and rear axle of the tractor were analyzed in a digital computer, by an algorithm based on the multiple correlation method. The optimum assembly of operating frequencies, by use of which the errors in measurement were minimized, was selected from the entire frequency spectrum. Selected frequencies are necessary for choosing the measurement range of the diagnostic device. It turned out that, to obtain a relative error of no more than 2%, it was sufficient to use two filters, vibrating only at the frequencies carrying the maximum data of the mechanical parameter being investigated. The measurement system consists of frequency-selection filters, amplifiers and quadratic detectors, at the outlets of which constant voltages are created, which are proportional to the signal level at the frequencies selected.
Osovskiy, V. I.↗
S-191 sensor performance evaluation
A final analysis was performed on the Skylab S-191 spectrometer data received from missions SL-2, SL-3, and SL-4. The repeatability and accuracy of the S-191 spectroradiometric internal calibration was determined by correlation to the output obtained from well-defined external targets. These included targets on the moon and earth as well as deep space. In addition, the accuracy of the S-191 short wavelength autocalibration was flight checked by correlation of the earth resources experimental package S-191 outputs and the Backup Unit S-191 outputs after viewing selected targets on the moon.
Hughes, C. L.↗
Vibrationally excited silicon monoxide masers
Published data on a select group of SiO maser sources have been analyzed for velocity variations as a function of phase. No apparent correlation was found to a level of about 2 km/s. This places constraints on the location of the maser molecules. Such a correlation should be present at some level. The implications for future high resolution infrared measurements are discussed.
Buhl, D.↗
Aerodynamic features of designed strake-wing configurations
Sixteen analytically and empirically designed strakes have been aerodynamically tested on a common wing-body to determine the longitudinal characteristics of the configurations. These strakes were selected, in general, due to their superior performance in a water-tunnel test. There they exhibited a good correlation between the hypothesized high value of angle of attack for strake vortex breakdown and the high value of leading-edge suction at the strake tip. The lift and pitch data were reasonably well predicted by an extended suction analogy method, and the lift agreement improved with increasing strake area. The strake-vortex-breakdown angle and configuration maximum lift generally increase with increasing strake area and, to some extent, strake tip leading-edge suction value. The best strake configurations all developed about the same maximum area efficiency value despite their differences in size.
Lamar, J. E.↗
Relationship of strength of turbulence to received power
Because of contributions due to reflection, the determination of the turbulence refractive index structure constant may be affected. For pure scattering from turbulence in the inertial subrange, the radar echo power can be used to calculate the refractive index structure constant. The radar power is determined by a convolution integral. If the antenna beam is swung to sufficiently large off-zenith angles ( 12.5 deg) so that a quasi-isotropic response from the tail ends of the Gaussian angular distribution can be anticipated, the evaluation of the convolution integral depends only on the known antenna pattern of the radar. This procedure, swinging the radar beam to attenuate the reflected component, may be called angular or direction filtering. The tilted antenna also may be pick up reflected components from near the zenith through the sidelobes. This can be tested by the evaluation of the correlation function. This method applies a time domain filtering of the intensity time series but needs a very careful selection of the high pass filters.
Rottger, J.↗
Complexes of polyadenylic acid and the methyl esters of amino acids
A study of amino acid methyl esters binding to polyadenylic acid supports the theory that the genetic code originated through weak but selective affinities between amino acids and nucleotides. NMR, insoluble complex analysis, and ultraviolet spectroscopy are used to illustrate a correlation between the hydrophybicities of A amino acids and their binding constants, which, beginning with the largest, are in the order of Phe (having nominally a hydrophobic AAA anticodon), Ile, Leu, Val and Gly (having a hydrophilic anticodon with no A). In general, the binding constants are twice the values by Reuben and Polk (1980) for monomeric AMP, which suggests that polymer amino acids are interacting with only one base. No real differences are found betwen poly A binding for free Phe, Phe methyl ester or Phe amide, except that the amide value is slightly lower.
Khaled, M. A.↗
Single beam synthesis from thinned arrays
Radio astronomers have investigated spatial frequencies and their relationship to apertures with the objective to improve the resolution in radio observations. Welch (1965) has related Fourier transform theory developed for linear communications to aperture design problems, while Fakley (1959) has conducted a comparison between the performances of a time-averaged product array and an intraclass correlator. The present investigation is concerned with an approach which resembles very closely the intraclass correlator system considered by Fakley. A description is presented of a process whereby a thinned array of elements samples selected spatial frequencies from a uniform signal wave front incident on the array. The spatial frequencies are used to generate a set of synthetic spatial frequencies which behave as though they had been sampled by a fully filled array. Beam formation is obtained by summing the set of synthetic spatial frequencies.
Kaiser, J. A., Jr.↗
Evaluation of seals for high-performance cryogenic turbomachines
An approach to computing flow and dynamic characteristics for seals or bearings is discussed. The local average velocity was strongly influenced by inlet and exit effects and fluid injection, which in turn drove zones of secondary flow. For the restricted three-dimensional model considered, the integral averaged results were in reasonable agreement with selected data. Unidirectional pressure measurements alone were insufficient to define such flow variations. However, for seal and bearing leakage correlations the principles of corresponding states were found to be useful. Also discussed are three phenomena encountered during testing of three eccentric nonrotating seal configurations for the Space Shuttle Main Engine (SSME) Program. Fluid injection, choking within a seal, and pressure profile crossover are related to postulated zones of secondary flow or separation and to direct stiffness.
Hendricks, R. C.↗
Oceanographic applications of laser technology
Oceanographic activities with the Airborne Oceanographic Lidar (AOL) for the past several years have primarily been focussed on using active (laser induced pigment fluorescence) and concurrent passive ocean color spectra to improve existing ocean color algorithms for estimating primary production in the world's oceans. The most significant results were the development of a technique for selecting optimal passive wavelengths for recovering phytoplankton photopigment concentration and the application of this technique, termed active-passive correlation spectroscopy (APCS), to various forms of passive ocean color algorithms. Included in this activity is use of airborne laser and passive ocean color for development of advanced satellite ocean color sensors. Promising on-wavelength subsurface scattering layer measurements were recently obtained. A partial summary of these results are shown.
Hoge, F. E.↗