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Sample records for accurate energy analysis

  1. A DPF Analysis Yields Quantum Mechanically Accurate Analytic Potential Energy Functions for the a ^1Σ^+ and X ^1Σ^+ States of NaH

    NASA Astrophysics Data System (ADS)

    Le Roy, Robert J.; Walji, Sadru; Sentjens, Katherine

    2013-06-01

    Alkali hydride diatomic molecules have long been the object of spectroscopic studies. However, their small reduced mass makes them species for which the conventional semiclassical-based methods of analysis tend to have the largest errors. To date, the only quantum-mechanically accurate direct-potential-fit (DPF) analysis for one of these molecules was the one for LiH reported by Coxon and Dickinson. The present paper extends this level of analysis to NaH, and reports a DPF analysis of all available spectroscopic data for the A ^1Σ^+-X ^1Σ^+ system of NaH which yields analytic potential energy functions for these two states that account for those data (on average) to within the experimental uncertainties. W.C. Stwalley, W.T. Zemke and S.C. Yang, J. Phys. Chem. Ref. Data {20}, 153-187 (1991). J.A. Coxon and C.S. Dickinson, J. Chem. Phys. {121}, 8378 (2004).

  2. Accurate Analysis of Array References

    DTIC Science & Technology

    1992-09-22

    This thesis addresses the problem of data dependence analysis, the base step in detecting loop level parallelism in scientific programs. Traditional...data dependence analysis research has concentrated on the simpler problem of affine memory disambiguation. Many algorithms have been developed that...can devise an experiment to test the effectiveness of affine memory disambiguation at approximating the full dependence problem. We discover that the

  3. Accurate ab initio vibrational energies of methyl chloride

    SciTech Connect

    Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2015-06-28

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH{sub 3}{sup 35}Cl and CH{sub 3}{sup 37}Cl. The respective PESs, CBS-35{sup  HL}, and CBS-37{sup  HL}, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY {sub 3}Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35{sup  HL} and CBS-37{sup  HL} PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm{sup −1}, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH{sub 3}Cl without empirical refinement of the respective PESs.

  4. Accurate spectral numerical schemes for kinetic equations with energy diffusion

    NASA Astrophysics Data System (ADS)

    Wilkening, Jon; Cerfon, Antoine J.; Landreman, Matt

    2015-08-01

    We examine the merits of using a family of polynomials that are orthogonal with respect to a non-classical weight function to discretize the speed variable in continuum kinetic calculations. We consider a model one-dimensional partial differential equation describing energy diffusion in velocity space due to Fokker-Planck collisions. This relatively simple case allows us to compare the results of the projected dynamics with an expensive but highly accurate spectral transform approach. It also allows us to integrate in time exactly, and to focus entirely on the effectiveness of the discretization of the speed variable. We show that for a fixed number of modes or grid points, the non-classical polynomials can be many orders of magnitude more accurate than classical Hermite polynomials or finite-difference solvers for kinetic equations in plasma physics. We provide a detailed analysis of the difference in behavior and accuracy of the two families of polynomials. For the non-classical polynomials, if the initial condition is not smooth at the origin when interpreted as a three-dimensional radial function, the exact solution leaves the polynomial subspace for a time, but returns (up to roundoff accuracy) to the same point evolved to by the projected dynamics in that time. By contrast, using classical polynomials, the exact solution differs significantly from the projected dynamics solution when it returns to the subspace. We also explore the connection between eigenfunctions of the projected evolution operator and (non-normalizable) eigenfunctions of the full evolution operator, as well as the effect of truncating the computational domain.

  5. Accurate nuclear radii and binding energies from a chiral interaction

    DOE PAGES

    Ekstrom, Jan A.; Jansen, G. R.; Wendt, Kyle A.; ...

    2015-05-01

    With the goal of developing predictive ab initio capability for light and medium-mass nuclei, two-nucleon and three-nucleon forces from chiral effective field theory are optimized simultaneously to low-energy nucleon-nucleon scattering data, as well as binding energies and radii of few-nucleon systems and selected isotopes of carbon and oxygen. Coupled-cluster calculations based on this interaction, named NNLOsat, yield accurate binding energies and radii of nuclei up to 40Ca, and are consistent with the empirical saturation point of symmetric nuclear matter. In addition, the low-lying collective Jπ=3- states in 16O and 40Ca are described accurately, while spectra for selected p- and sd-shellmore » nuclei are in reasonable agreement with experiment.« less

  6. Accurate nuclear radii and binding energies from a chiral interaction

    SciTech Connect

    Ekstrom, Jan A.; Jansen, G. R.; Wendt, Kyle A.; Hagen, Gaute; Papenbrock, Thomas F.; Carlsson, Boris; Forssen, Christian; Hjorth-Jensen, M.; Navratil, Petr; Nazarewicz, Witold

    2015-05-01

    With the goal of developing predictive ab initio capability for light and medium-mass nuclei, two-nucleon and three-nucleon forces from chiral effective field theory are optimized simultaneously to low-energy nucleon-nucleon scattering data, as well as binding energies and radii of few-nucleon systems and selected isotopes of carbon and oxygen. Coupled-cluster calculations based on this interaction, named NNLOsat, yield accurate binding energies and radii of nuclei up to 40Ca, and are consistent with the empirical saturation point of symmetric nuclear matter. In addition, the low-lying collective Jπ=3- states in 16O and 40Ca are described accurately, while spectra for selected p- and sd-shell nuclei are in reasonable agreement with experiment.

  7. Inverter Modeling For Accurate Energy Predictions Of Tracking HCPV Installations

    NASA Astrophysics Data System (ADS)

    Bowman, J.; Jensen, S.; McDonald, Mark

    2010-10-01

    High efficiency high concentration photovoltaic (HCPV) solar plants of megawatt scale are now operational, and opportunities for expanded adoption are plentiful. However, effective bidding for sites requires reliable prediction of energy production. HCPV module nameplate power is rated for specific test conditions; however, instantaneous HCPV power varies due to site specific irradiance and operating temperature, and is degraded by soiling, protective stowing, shading, and electrical connectivity. These factors interact with the selection of equipment typically supplied by third parties, e.g., wire gauge and inverters. We describe a time sequence model accurately accounting for these effects that predicts annual energy production, with specific reference to the impact of the inverter on energy output and interactions between system-level design decisions and the inverter. We will also show two examples, based on an actual field design, of inverter efficiency calculations and the interaction between string arrangements and inverter selection.

  8. Accurate energy levels for singly ionized platinum (Pt II)

    NASA Technical Reports Server (NTRS)

    Reader, Joseph; Acquista, Nicolo; Sansonetti, Craig J.; Engleman, Rolf, Jr.

    1988-01-01

    New observations of the spectrum of Pt II have been made with hollow-cathode lamps. The region from 1032 to 4101 A was observed photographically with a 10.7-m normal-incidence spectrograph. The region from 2245 to 5223 A was observed with a Fourier-transform spectrometer. Wavelength measurements were made for 558 lines. The uncertainties vary from 0.0005 to 0.004 A. From these measurements and three parity-forbidden transitions in the infrared, accurate values were determined for 28 even and 72 odd energy levels of Pt II.

  9. Accurate Energy Transaction Allocation using Path Integration and Interpolation

    NASA Astrophysics Data System (ADS)

    Bhide, Mandar Mohan

    This thesis investigates many of the popular cost allocation methods which are based on actual usage of the transmission network. The Energy Transaction Allocation (ETA) method originally proposed by A.Fradi, S.Brigonne and B.Wollenberg which gives unique advantage of accurately allocating the transmission network usage is discussed subsequently. Modified calculation of ETA based on simple interpolation technique is then proposed. The proposed methodology not only increase the accuracy of calculation but also decreases number of calculations to less than half of the number of calculations required in original ETAs.

  10. Accurate bond dissociation energies (D 0) for FHF- isotopologues

    NASA Astrophysics Data System (ADS)

    Stein, Christopher; Oswald, Rainer; Sebald, Peter; Botschwina, Peter; Stoll, Hermann; Peterson, Kirk A.

    2013-09-01

    Accurate bond dissociation energies (D 0) are determined for three isotopologues of the bifluoride ion (FHF-). While the zero-point vibrational contributions are taken from our previous work (P. Sebald, A. Bargholz, R. Oswald, C. Stein, P. Botschwina, J. Phys. Chem. A, DOI: 10.1021/jp3123677), the equilibrium dissociation energy (D e ) of the reaction ? was obtained by a composite method including frozen-core (fc) CCSD(T) calculations with basis sets up to cardinal number n = 7 followed by extrapolation to the complete basis set limit. Smaller terms beyond fc-CCSD(T) cancel each other almost completely. The D 0 values of FHF-, FDF-, and FTF- are predicted to be 15,176, 15,191, and 15,198 cm-1, respectively, with an uncertainty of ca. 15 cm-1.

  11. A highly accurate ab initio potential energy surface for methane

    NASA Astrophysics Data System (ADS)

    Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2016-09-01

    A new nine-dimensional potential energy surface (PES) for methane has been generated using state-of-the-art ab initio theory. The PES is based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit and incorporates a range of higher-level additive energy corrections. These include core-valence electron correlation, higher-order coupled cluster terms beyond perturbative triples, scalar relativistic effects, and the diagonal Born-Oppenheimer correction. Sub-wavenumber accuracy is achieved for the majority of experimentally known vibrational energy levels with the four fundamentals of 12CH4 reproduced with a root-mean-square error of 0.70 cm-1. The computed ab initio equilibrium C-H bond length is in excellent agreement with previous values despite pure rotational energies displaying minor systematic errors as J (rotational excitation) increases. It is shown that these errors can be significantly reduced by adjusting the equilibrium geometry. The PES represents the most accurate ab initio surface to date and will serve as a good starting point for empirical refinement.

  12. Accurate NMR structures through minimization of an extended hybrid energy.

    PubMed

    Nilges, Michael; Bernard, Aymeric; Bardiaux, Benjamin; Malliavin, Thérèse; Habeck, Michael; Rieping, Wolfgang

    2008-09-10

    The use of generous distance bounds has been the hallmark of NMR structure determination. However, bounds necessitate the estimation of data quality before the calculation, reduce the information content, introduce human bias, and allow for major errors in the structures. Here, we propose a new rapid structure calculation scheme based on Bayesian analysis. The minimization of an extended energy function, including a new type of distance restraint and a term depending on the data quality, results in an estimation of the data quality in addition to coordinates. This allows for the determination of the optimal weight on the experimental information. The resulting structures are of better quality and closer to the X-ray crystal structure of the same molecule. With the new calculation approach, the analysis of discrepancies from the target distances becomes meaningful. The strategy may be useful in other applications-for example, in homology modeling.

  13. The Calculation of Accurate Metal-Ligand Bond Energies

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W.; Partridge, Harry, III; Ricca, Alessandra; Arnold, James O. (Technical Monitor)

    1997-01-01

    The optimization of the geometry and calculation of zero-point energies are carried out at the B3LYP level of theory. The bond energies are determined at this level, as well as at the CCSD(T) level using very large basis sets. The successive OH bond energies to the first row transition metal cations are reported. For most systems there has been an experimental determination of the first OH. In general, the CCSD(T) values are in good agreement with experiment. The bonding changes from mostly covalent for the early metals to mostly electrostatic for the late transition metal systems.

  14. Energy Analysis.

    ERIC Educational Resources Information Center

    Bazjanac, Vladimir

    1981-01-01

    The Aquatic Center at Corvallis (Oregon) is analyzed for energy use. Energy conservation in the building would be accomplished best through heavy insulation of exterior surfaces and the maximization of passive solar gain. (Author/MLF)

  15. An accurate determination of the surface energy of solid selenium

    NASA Astrophysics Data System (ADS)

    Guisbiers, G.; Arscott, S.; Snyders, R.

    2012-12-01

    Selenium is currently a key element for developing nano and micro-technologies. Nevertheless, the surface energy of solid selenium (γSe) reported in the literature is still questionable. In this work, we have measured γSe = 0.291 ± 0.025 J/m2 at 293 K using the sessile drop technique with different probe liquids, namely ethylene glycol, de-ionized water, mercury, and gallium. This value is in excellent agreement with theoretical predictions.

  16. An Accurate Potential Energy Surface for H2O

    NASA Technical Reports Server (NTRS)

    Schwenke, David W.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    We have carried out extensive high quality ab initio electronic structure calculations of the ground state potential energy surface (PES) and dipole moment function (DMF) for H2O. A small adjustment is made to the PES to improve the agreement of line positions from theory and experiment. The theoretical line positions are obtained from variational ro-vibrational calculations using the exact kinetic energy operator. For the lines being fitted, the root-mean-square error was reduced from 6.9 to 0.08 /cm. We were then able to match 30,092 of the 30,117 lines from the HITRAN 96 data base to theoretical lines, and 80% of the line positions differed less than 0.1 /cm. About 3% of the line positions in the experimental data base appear to be incorrect. Theory predicts the existence of many additional weak lines with intensities above the cutoff used in the data base. To obtain results of similar accuracy for HDO, a mass dependent correction to the PH is introduced and is parameterized by simultaneously fitting line positions for HDO and D2O. The mass dependent PH has good predictive value for T2O and HTO. Nonadiabatic effects are not explicitly included. Line strengths for vibrational bands summed over rotational levels usually agree well between theory and experiment, but individual line strengths can differ greatly. A high temperature line list containing about 380 million lines has been generated using the present PES and DMF

  17. Accurate stone analysis: the impact on disease diagnosis and treatment.

    PubMed

    Mandel, Neil S; Mandel, Ian C; Kolbach-Mandel, Ann M

    2017-02-01

    This manuscript reviews the requirements for acceptable compositional analysis of kidney stones using various biophysical methods. High-resolution X-ray powder diffraction crystallography and Fourier transform infrared spectroscopy (FTIR) are the only acceptable methods in our labs for kidney stone analysis. The use of well-constructed spectral reference libraries is the basis for accurate and complete stone analysis. The literature included in this manuscript identify errors in most commercial laboratories and in some academic centers. We provide personal comments on why such errors are occurring at such high rates, and although the work load is rather large, it is very worthwhile in providing accurate stone compositions. We also provide the results of our almost 90,000 stone analyses and a breakdown of the number of components we have observed in the various stones. We also offer advice on determining the method used by the various FTIR equipment manufacturers who also provide a stone analysis library so that the FTIR users can feel comfortable in the accuracy of their reported results. Such an analysis on the accuracy of the individual reference libraries could positively influence the reduction in their respective error rates.

  18. Residential Building Energy Analysis

    SciTech Connect

    Ritschard, R. L.

    1990-09-01

    PEAR (Program for Energy Analysis of Residences) provides an easy-to-use and accurate method of estimating the energy and cost savings associated with various energy conservation measures in site-built single-family homes. Measures such as ceiling, wall, and floor insulation; different window type and glazing layers; infiltration levels; and equipment efficiency can be considered. PEAR also allows the user to consider the effects of roof and wall color, movable night insulation on the windows, reflective and heat absorbing glass, an attached sunspace, and use of a night temperature setback. Regression techniques permit adjustments for different building geometries, window areas and orientations, wall construction, and extension of the data to 880 U.S. locations determined by climate parameters. Based on annual energy savings, user-specified costs of conservation measures, fuel, lifetime of measure, loan period, and fuel escalation and interest rates, PEAR calculates two economic indicators; the Simple Payback Period (SPP) and the Savings-to-Investment Ratio (SIR). Energy and cost savings of different sets of conservation measures can be compared in a single run. The program can be used both as a research tool by energy policy analysts and as a method for nontechnical energy calculation by architects, home builders, home owners, and others in the building industry.

  19. Accurate interlaminar stress recovery from finite element analysis

    NASA Technical Reports Server (NTRS)

    Tessler, Alexander; Riggs, H. Ronald

    1994-01-01

    The accuracy and robustness of a two-dimensional smoothing methodology is examined for the problem of recovering accurate interlaminar shear stress distributions in laminated composite and sandwich plates. The smoothing methodology is based on a variational formulation which combines discrete least-squares and penalty-constraint functionals in a single variational form. The smoothing analysis utilizes optimal strains computed at discrete locations in a finite element analysis. These discrete strain data are smoothed with a smoothing element discretization, producing superior accuracy strains and their first gradients. The approach enables the resulting smooth strain field to be practically C1-continuous throughout the domain of smoothing, exhibiting superconvergent properties of the smoothed quantity. The continuous strain gradients are also obtained directly from the solution. The recovered strain gradients are subsequently employed in the integration o equilibrium equations to obtain accurate interlaminar shear stresses. The problem is a simply-supported rectangular plate under a doubly sinusoidal load. The problem has an exact analytic solution which serves as a measure of goodness of the recovered interlaminar shear stresses. The method has the versatility of being applicable to the analysis of rather general and complex structures built of distinct components and materials, such as found in aircraft design. For these types of structures, the smoothing is achieved with 'patches', each patch covering the domain in which the smoothed quantity is physically continuous.

  20. Combining MFD and PIE for accurate single-pair Förster resonance energy transfer measurements.

    PubMed

    Kudryavtsev, Volodymyr; Sikor, Martin; Kalinin, Stanislav; Mokranjac, Dejana; Seidel, Claus A M; Lamb, Don C

    2012-03-01

    Single-pair Förster resonance energy transfer (spFRET) experiments using single-molecule burst analysis on a confocal microscope are an ideal tool to measure inter- and intramolecular distances and dynamics on the nanoscale. Different techniques have been developed to maximize the amount of information available in spFRET burst analysis experiments. Multiparameter fluorescence detection (MFD) is used to monitor a variety of fluorescence parameters simultaneously and pulsed interleaved excitation (PIE) employs direct excitation of the acceptor to probe its presence and photoactivity. To calculate accurate FRET efficiencies from spFRET experiments with MFD or PIE, several calibration measurements are usually required. Herein, we demonstrate that by combining MFD with PIE information regarding all calibration factors as well as an accurate determination of spFRET histograms can be performed in a single measurement. In addition, the quality of overlap of the different detection volumes as well as the detection of acceptor photophysics can be investigated with MFD-PIE. Bursts containing acceptor photobleaching can be identified and excluded from further investigation while bursts that contain FRET dynamics are unaffected by this analysis. We have employed MFD-PIE to accurately analyze the effects of nucleotides and substrate on the interdomain separation in DnaK, the major bacterial heat shock protein 70 (Hsp70). The interdomain distance increases from 47 Å in the ATP-bound state to 84 Å in the ADP-bound state and slightly contracts to 77 Å when a substrate is bound. This is in contrast to what was observed for the mitochondrial member of the Hsp70s, Ssc1, supporting the notion of evolutionary specialization of Hsp70s for different cellular functions in different organisms and cell organelles.

  1. Low-energy structures of benzene clusters with a novel accurate potential surface.

    PubMed

    Bartolomei, M; Pirani, F; Marques, J M C

    2015-12-05

    The benzene-benzene (Bz-Bz) interaction is present in several chemical systems and it is known to be crucial in understanding the specificity of important biological phenomena. In this work, we propose a novel Bz-Bz analytical potential energy surface which is fine-tuned on accurate ab initio calculations in order to improve its reliability. Once the Bz-Bz interaction is modeled, an analytical function for the energy of the Bzn clusters may be obtained by summing up over all pair potentials. We apply an evolutionary algorithm (EA) to discover the lowest-energy structures of Bzn clusters (for n=2-25), and the results are compared with previous global optimization studies where different potential functions were employed. Besides the global minimum, the EA also gives the structures of other low-lying isomers ranked by the corresponding energy. Additional ab initio calculations are carried out for the low-lying isomers of Bz3 and Bz4 clusters, and the global minimum is confirmed as the most stable structure for both sizes. Finally, a detailed analysis of the low-energy isomers of the n = 13 and 19 magic-number clusters is performed. The two lowest-energy Bz13 isomers show S6 and C3 symmetry, respectively, which is compatible with the experimental results available in the literature. The Bz19 structures reported here are all non-symmetric, showing two central Bz molecules surrounded by 12 nearest-neighbor monomers in the case of the five lowest-energy structures.

  2. Electron Microprobe Analysis Techniques for Accurate Measurements of Apatite

    NASA Astrophysics Data System (ADS)

    Goldoff, B. A.; Webster, J. D.; Harlov, D. E.

    2010-12-01

    Apatite [Ca5(PO4)3(F, Cl, OH)] is a ubiquitous accessory mineral in igneous, metamorphic, and sedimentary rocks. The mineral contains halogens and hydroxyl ions, which can provide important constraints on fugacities of volatile components in fluids and other phases in igneous and metamorphic environments in which apatite has equilibrated. Accurate measurements of these components in apatite are therefore necessary. Analyzing apatite by electron microprobe (EMPA), which is a commonly used geochemical analytical technique, has often been found to be problematic and previous studies have identified sources of error. For example, Stormer et al. (1993) demonstrated that the orientation of an apatite grain relative to the incident electron beam could significantly affect the concentration results. In this study, a variety of alternative EMPA operating conditions for apatite analysis were investigated: a range of electron beam settings, count times, crystal grain orientations, and calibration standards were tested. Twenty synthetic anhydrous apatite samples that span the fluorapatite-chlorapatite solid solution series, and whose halogen concentrations were determined by wet chemistry, were analyzed. Accurate measurements of these samples were obtained with many EMPA techniques. One effective method includes setting a static electron beam to 10-15nA, 15kV, and 10 microns in diameter. Additionally, the apatite sample is oriented with the crystal’s c-axis parallel to the slide surface and the count times are moderate. Importantly, the F and Cl EMPA concentrations are in extremely good agreement with the wet-chemical data. We also present EMPA operating conditions and techniques that are problematic and should be avoided. J.C. Stormer, Jr. et al., Am. Mineral. 78 (1993) 641-648.

  3. Methods for Efficiently and Accurately Computing Quantum Mechanical Free Energies for Enzyme Catalysis.

    PubMed

    Kearns, F L; Hudson, P S; Boresch, S; Woodcock, H L

    2016-01-01

    Enzyme activity is inherently linked to free energies of transition states, ligand binding, protonation/deprotonation, etc.; these free energies, and thus enzyme function, can be affected by residue mutations, allosterically induced conformational changes, and much more. Therefore, being able to predict free energies associated with enzymatic processes is critical to understanding and predicting their function. Free energy simulation (FES) has historically been a computational challenge as it requires both the accurate description of inter- and intramolecular interactions and adequate sampling of all relevant conformational degrees of freedom. The hybrid quantum mechanical molecular mechanical (QM/MM) framework is the current tool of choice when accurate computations of macromolecular systems are essential. Unfortunately, robust and efficient approaches that employ the high levels of computational theory needed to accurately describe many reactive processes (ie, ab initio, DFT), while also including explicit solvation effects and accounting for extensive conformational sampling are essentially nonexistent. In this chapter, we will give a brief overview of two recently developed methods that mitigate several major challenges associated with QM/MM FES: the QM non-Boltzmann Bennett's acceptance ratio method and the QM nonequilibrium work method. We will also describe usage of these methods to calculate free energies associated with (1) relative properties and (2) along reaction paths, using simple test cases with relevance to enzymes examples.

  4. Accurate Hartree-Fock energy of extended systems using large Gaussian basis sets

    NASA Astrophysics Data System (ADS)

    Paier, Joachim; Diaconu, Cristian V.; Scuseria, Gustavo E.; Guidon, Manuel; Vandevondele, Joost; Hutter, Jürg

    2009-11-01

    Calculating highly accurate thermochemical properties of condensed matter via wave-function-based approaches (such as, e.g., Hartree-Fock or hybrid functionals) has recently attracted much interest. We here present two strategies providing accurate Hartree-Fock energies for solid LiH in a large Gaussian basis set and applying periodic boundary conditions. The total energies were obtained using two different approaches, namely, a supercell evaluation of Hartree-Fock exchange using a truncated Coulomb operator and an extrapolation toward the full-range Hartree-Fock limit of a Padé fit to a series of short-range screened Hartree-Fock calculations. These two techniques agreed to significant precision. We also present the Hartree-Fock cohesive energy of LiH (converged to within sub-millielectron volt) at the experimental equilibrium volume as well as the Hartree-Fock equilibrium lattice constant and bulk modulus.

  5. A Cavity Corrected 3D-RISM Functional for Accurate Solvation Free Energies

    PubMed Central

    2014-01-01

    We show that an Ng bridge function modified version of the three-dimensional reference interaction site model (3D-RISM-NgB) solvation free energy method can accurately predict the hydration free energy (HFE) of a set of 504 organic molecules. To achieve this, a single unique constant parameter was adjusted to the computed HFE of single atom Lennard-Jones solutes. It is shown that 3D-RISM is relatively accurate at predicting the electrostatic component of the HFE without correction but requires a modification of the nonpolar contribution that originates in the formation of the cavity created by the solute in water. We use a free energy functional with the Ng scaling of the direct correlation function [Ng, K. C. J. Chem. Phys.1974, 61, 2680]. This produces a rapid, reliable small molecule HFE calculation for applications in drug design. PMID:24634616

  6. Automatic generation of reaction energy databases from highly accurate atomization energy benchmark sets.

    PubMed

    Margraf, Johannes T; Ranasinghe, Duminda S; Bartlett, Rodney J

    2017-03-31

    In this contribution, we discuss how reaction energy benchmark sets can automatically be created from arbitrary atomization energy databases. As an example, over 11 000 reaction energies derived from the W4-11 database, as well as some relevant subsets are reported. Importantly, there is only very modest computational overhead involved in computing >11 000 reaction energies compared to 140 atomization energies, since the rate-determining step for either benchmark is performing the same 140 quantum chemical calculations. The performance of commonly used electronic structure methods for the new database is analyzed. This allows investigating the relationship between the performances for atomization and reaction energy benchmarks based on an identical set of molecules. The atomization energy is found to be a weak predictor for the overall usefulness of a method. The performance of density functional approximations in light of the number of empirically optimized parameters used in their design is also discussed.

  7. Accurate prediction of adsorption energies on graphene, using a dispersion-corrected semiempirical method including solvation.

    PubMed

    Vincent, Mark A; Hillier, Ian H

    2014-08-25

    The accurate prediction of the adsorption energies of unsaturated molecules on graphene in the presence of water is essential for the design of molecules that can modify its properties and that can aid its processability. We here show that a semiempirical MO method corrected for dispersive interactions (PM6-DH2) can predict the adsorption energies of unsaturated hydrocarbons and the effect of substitution on these values to an accuracy comparable to DFT values and in good agreement with the experiment. The adsorption energies of TCNE, TCNQ, and a number of sulfonated pyrenes are also predicted, along with the effect of hydration using the COSMO model.

  8. Progress toward accurate high spatial resolution actinide analysis by EPMA

    NASA Astrophysics Data System (ADS)

    Jercinovic, M. J.; Allaz, J. M.; Williams, M. L.

    2010-12-01

    High precision, high spatial resolution EPMA of actinides is a significant issue for geochronology, resource geochemistry, and studies involving the nuclear fuel cycle. Particular interest focuses on understanding of the behavior of Th and U in the growth and breakdown reactions relevant to actinide-bearing phases (monazite, zircon, thorite, allanite, etc.), and geochemical fractionation processes involving Th and U in fluid interactions. Unfortunately, the measurement of minor and trace concentrations of U in the presence of major concentrations of Th and/or REEs is particularly problematic, especially in complexly zoned phases with large compositional variation on the micro or nanoscale - spatial resolutions now accessible with modern instruments. Sub-micron, high precision compositional analysis of minor components is feasible in very high Z phases where scattering is limited at lower kV (15kV or less) and where the beam diameter can be kept below 400nm at high current (e.g. 200-500nA). High collection efficiency spectrometers and high performance electron optics in EPMA now allow the use of lower overvoltage through an exceptional range in beam current, facilitating higher spatial resolution quantitative analysis. The U LIII edge at 17.2 kV precludes L-series analysis at low kV (high spatial resolution), requiring careful measurements of the actinide M series. Also, U-La detection (wavelength = 0.9A) requires the use of LiF (220) or (420), not generally available on most instruments. Strong peak overlaps of Th on U make highly accurate interference correction mandatory, with problems compounded by the ThMIV and ThMV absorption edges affecting peak, background, and interference calibration measurements (especially the interference of the Th M line family on UMb). Complex REE bearing phases such as monazite, zircon, and allanite have particularly complex interference issues due to multiple peak and background overlaps from elements present in the activation

  9. Exchange-Hole Dipole Dispersion Model for Accurate Energy Ranking in Molecular Crystal Structure Prediction.

    PubMed

    Whittleton, Sarah R; Otero-de-la-Roza, A; Johnson, Erin R

    2017-02-14

    Accurate energy ranking is a key facet to the problem of first-principles crystal-structure prediction (CSP) of molecular crystals. This work presents a systematic assessment of B86bPBE-XDM, a semilocal density functional combined with the exchange-hole dipole moment (XDM) dispersion model, for energy ranking using 14 compounds from the first five CSP blind tests. Specifically, the set of crystals studied comprises 11 rigid, planar compounds and 3 co-crystals. The experimental structure was correctly identified as the lowest in lattice energy for 12 of the 14 total crystals. One of the exceptions is 4-hydroxythiophene-2-carbonitrile, for which the experimental structure was correctly identified once a quasi-harmonic estimate of the vibrational free-energy contribution was included, evidencing the occasional importance of thermal corrections for accurate energy ranking. The other exception is an organic salt, where charge-transfer error (also called delocalization error) is expected to cause the base density functional to be unreliable. Provided the choice of base density functional is appropriate and an estimate of temperature effects is used, XDM-corrected density-functional theory is highly reliable for the energetic ranking of competing crystal structures.

  10. Accurate studies of dissociation energies and vibrational energies on alkali metals

    NASA Astrophysics Data System (ADS)

    Liu, Xiu-Ying; Sun, Wei-Guo; Fan, Qun-Chao

    2008-06-01

    This paper studies full vibrational spectra {Ev} and molecular dissociation energies De by using conventional least-squares (LS) fitting and an algebraic method (AM) proposed recently for 10 diatomic electronic states of 7Li2, Na2, NaK and NaLi molecules based on some known experimental vibrational energies in a subset [Evexpt] respectively. Studies show that: (1) although both the full AM spectrum {EvAM} and the LS spectrum {EvLS} can reproduce the known experimental energies in [Evexpt], the {EvAM} is superior to the {EvLS} in that the high-lying AM vibrational energies which may not be available experimentally have better or much better accuracy than those LS counterparts in {EvLS}, and so is the AM dissociation energy DeAM; (2) the main source of the errors in the data obtained by using the LS fitting is that the fitting which is just a pure mathematical process does not use any physical criteria that must be satisfied by the full vibrational spectrum, while the AM method does. This study suggests that when fitting or solving a physical equation using a set of source data, it is important not only to apply a proper mathematical tool, but also to use correct physical criteria which measure the physical properties of the data, kick out those data having bigger errors, and impose conditional convergence on the numerical process.

  11. Accurate Zero Parameter Correlation Energy Functional Obtained from the Homogeneous Electron Gas with an Energy Gap

    NASA Astrophysics Data System (ADS)

    Krieger, J. B.; Chen, Jiqiang; Iafrate, G. J.; Savin, A.

    1998-03-01

    We have obtained an analytic approximation to E_c(r_g, ζ,G) where G is an energy gap separating the occupied and unoccupied states of a homogeneous electron gas for ζ=3D0 and ξ=3D1. When G=3D0, E_c(r_g, ζ) reduces to the usual LSD result. This functional is employed in calculating correlation energies for unpolarized atoms and ions for Z <= 18 by taking G[n]=3D1/8|nabla ln n|^2, which reduces to the ionization energy in the large r limit in an exact Kohn-Sham (KS) theory. The resulting functional is self-interaction-corrected employing a method which is invariant under a unitary transformation. We find that the application of this approach to the calculation of the Ec functional reduces the error in the LSD result by more than 95%. When the value of G is approximately corrected to include the effect of higher lying unoccupied localized states, the resulting values of Ec are within a few percent of the exact results.

  12. Accurate Evaluation of the Dispersion Energy in the Simulation of Gas Adsorption into Porous Zeolites.

    PubMed

    Fraccarollo, Alberto; Canti, Lorenzo; Marchese, Leonardo; Cossi, Maurizio

    2017-03-07

    The force fields used to simulate the gas adsorption in porous materials are strongly dominated by the van der Waals (vdW) terms. Here we discuss the delicate problem to estimate these terms accurately, analyzing the effect of different models. To this end, we simulated the physisorption of CH4, CO2, and Ar into various Al-free microporous zeolites (ITQ-29, SSZ-13, and silicalite-1), comparing the theoretical results with accurate experimental isotherms. The vdW terms in the force fields were parametrized against the free gas densities and high-level quantum mechanical (QM) calculations, comparing different methods to evaluate the dispersion energies. In particular, MP2 and DFT with semiempirical corrections, with suitable basis sets, were chosen to approximate the best QM calculations; either Lennard-Jones or Morse expressions were used to include the vdW terms in the force fields. The comparison of the simulated and experimental isotherms revealed that a strong interplay exists between the definition of the dispersion energies and the functional form used in the force field; these results are fairly general and reproducible, at least for the systems considered here. On this basis, the reliability of different models can be discussed, and a recipe can be provided to obtain accurate simulated adsorption isotherms.

  13. Ab Initio Potential Energy Surfaces and the Calculation of Accurate Vibrational Frequencies

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Dateo, Christopher E.; Martin, Jan M. L.; Taylor, Peter R.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Due to advances in quantum mechanical methods over the last few years, it is now possible to determine ab initio potential energy surfaces in which fundamental vibrational frequencies are accurate to within plus or minus 8 cm(exp -1) on average, and molecular bond distances are accurate to within plus or minus 0.001-0.003 Angstroms, depending on the nature of the bond. That is, the potential energy surfaces have not been scaled or empirically adjusted in any way, showing that theoretical methods have progressed to the point of being useful in analyzing spectra that are not from a tightly controlled laboratory environment, such as vibrational spectra from the interstellar medium. Some recent examples demonstrating this accuracy will be presented and discussed. These include the HNO, CH4, C2H4, and ClCN molecules. The HNO molecule is interesting due to the very large H-N anharmonicity, while ClCN has a very large Fermi resonance. The ab initio studies for the CH4 and C2H4 molecules present the first accurate full quartic force fields of any kind (i.e., whether theoretical or empirical) for a five-atom and six-atom system, respectively.

  14. Accurate nonrelativistic ground-state energies of 3d transition metal atoms

    SciTech Connect

    Scemama, A.; Applencourt, T.; Giner, E.; Caffarel, M.

    2014-12-28

    We present accurate nonrelativistic ground-state energies of the transition metal atoms of the 3d series calculated with Fixed-Node Diffusion Monte Carlo (FN-DMC). Selected multi-determinantal expansions obtained with the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) method and including the most prominent determinants of the full configuration interaction expansion are used as trial wavefunctions. Using a maximum of a few tens of thousands determinants, fixed-node errors on total DMC energies are found to be greatly reduced for some atoms with respect to those obtained with Hartree-Fock nodes. To the best of our knowledge, the FN-DMC/(CIPSI nodes) ground-state energies presented here are the lowest variational total energies reported so far. They differ from the recently recommended non-variational values of McCarthy and Thakkar [J. Chem. Phys. 136, 054107 (2012)] only by a few percents of the correlation energy. Thanks to the variational property of FN-DMC total energies, our results provide exact lower bounds for the absolute value of all-electron correlation energies, |E{sub c}|.

  15. Building energy analysis tool

    DOEpatents

    Brackney, Larry; Parker, Andrew; Long, Nicholas; Metzger, Ian; Dean, Jesse; Lisell, Lars

    2016-04-12

    A building energy analysis system includes a building component library configured to store a plurality of building components, a modeling tool configured to access the building component library and create a building model of a building under analysis using building spatial data and using selected building components of the plurality of building components stored in the building component library, a building analysis engine configured to operate the building model and generate a baseline energy model of the building under analysis and further configured to apply one or more energy conservation measures to the baseline energy model in order to generate one or more corresponding optimized energy models, and a recommendation tool configured to assess the one or more optimized energy models against the baseline energy model and generate recommendations for substitute building components or modifications.

  16. Energy Sector Market Analysis

    SciTech Connect

    Arent, D.; Benioff, R.; Mosey, G.; Bird, L.; Brown, J.; Brown, E.; Vimmerstedt, L.; Aabakken, J.; Parks, K.; Lapsa, M.; Davis, S.; Olszewski, M.; Cox, D.; McElhaney, K.; Hadley, S.; Hostick, D.; Nicholls, A.; McDonald, S.; Holloman, B.

    2006-10-01

    This paper presents the results of energy market analysis sponsored by the Department of Energy's (DOE) Weatherization and International Program (WIP) within the Office of Energy Efficiency and Renewable Energy (EERE). The analysis was conducted by a team of DOE laboratory experts from the National Renewable Energy Laboratory (NREL), Oak Ridge National Laboratory (ORNL), and Pacific Northwest National Laboratory (PNNL), with additional input from Lawrence Berkeley National Laboratory (LBNL). The analysis was structured to identify those markets and niches where government can create the biggest impact by informing management decisions in the private and public sectors. The analysis identifies those markets and niches where opportunities exist for increasing energy efficiency and renewable energy use.

  17. Toward an Accurate Estimate of the Exfoliation Energy of Black Phosphorus: A Periodic Quantum Chemical Approach.

    PubMed

    Sansone, Giuseppe; Maschio, Lorenzo; Usvyat, Denis; Schütz, Martin; Karttunen, Antti

    2016-01-07

    The black phosphorus (black-P) crystal is formed of covalently bound layers of phosphorene stacked together by weak van der Waals interactions. An experimental measurement of the exfoliation energy of black-P is not available presently, making theoretical studies the most important source of information for the optimization of phosphorene production. Here, we provide an accurate estimate of the exfoliation energy of black-P on the basis of multilevel quantum chemical calculations, which include the periodic local Møller-Plesset perturbation theory of second order, augmented by higher-order corrections, which are evaluated with finite clusters mimicking the crystal. Very similar results are also obtained by density functional theory with the D3-version of Grimme's empirical dispersion correction. Our estimate of the exfoliation energy for black-P of -151 meV/atom is substantially larger than that of graphite, suggesting the need for different strategies to generate isolated layers for these two systems.

  18. New accurate benchmark energies for large water clusters: DFT is better than expected.

    PubMed

    Anacker, Tony; Friedrich, Joachim

    2014-03-30

    In this work, we use MP2 and coupled-cluster with single, double, and perturbative triple excitations [CCSD(T)] as well as their corresponding explicitly correlated (F12) counterparts to compute the interaction energies of water icosamers. The incremental scheme is used to compute benchmark energies at the CCSD(T)/CBS(45) and CCSD(T)(F12*)/cc-pVQZ-F12 level of theory. The four structures, dodecahedron, edge sharing, face sharing, and fused cubes, are part of the WATER27 test set and therefore, highly accurate interaction energies are required. All methods applied in this work lead to new benchmark energies for these four systems. To obtain these values, we carefully analyze the convergence of the interaction energies with respect to the basis set. Furthermore, we investigate the influence of the basis set superposition error and the core-valence correlation. The interaction energies are: dodecahedron -198.6 kcal/mol, edge sharing -209.7 kcal/mol, face sharing -208.0 kcal/mol, and fused cubes -208.0 kcal/mol. For water clusters, we recommend to use the PW6B95 density functional of Truhlar in combination with Grimme's dispersion correction (D3), as the mean absolute error is 0.9 and the root mean-squared deviation is only 1.4 kcal/mol.

  19. Do Bond Functions Help for the Calculation of Accurate Bond Energies?

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Arnold, James (Technical Monitor)

    1998-01-01

    The bond energies of 8 chemically bound diatomics are computed using several basis sets with and without bond functions (BF). The bond energies obtained using the aug-pVnZ+BF basis sets (with a correction for basis set superposition error, BSSE) tend to be slightly smaller that the results obtained using the aug-pV(n+I)Z basis sets, but slightly larger than the BSSE corrected aug-pV(n+I)Z results. The aug-cc-pVDZ+BF and aug-cc-pVTZ+BF basis sets yield reasonable estimates of bond energies, but, in most cases, these results cannot be considered highly accurate. Extrapolation of the results obtained with basis sets including bond functions appears to be inferior to the results obtained by extrapolation using atom-centered basis sets. Therefore bond functions do not appear to offer a path for obtaining highly accurate results for chemically bound systems at a lower computational cost than atom centered basis sets.

  20. Quantitative proteomic analysis by accurate mass retention time pairs.

    PubMed

    Silva, Jeffrey C; Denny, Richard; Dorschel, Craig A; Gorenstein, Marc; Kass, Ignatius J; Li, Guo-Zhong; McKenna, Therese; Nold, Michael J; Richardson, Keith; Young, Phillip; Geromanos, Scott

    2005-04-01

    Current methodologies for protein quantitation include 2-dimensional gel electrophoresis techniques, metabolic labeling, and stable isotope labeling methods to name only a few. The current literature illustrates both pros and cons for each of the previously mentioned methodologies. Keeping with the teachings of William of Ockham, "with all things being equal the simplest solution tends to be correct", a simple LC/MS based methodology is presented that allows relative changes in abundance of proteins in highly complex mixtures to be determined. Utilizing a reproducible chromatographic separations system along with the high mass resolution and mass accuracy of an orthogonal time-of-flight mass spectrometer, the quantitative comparison of tens of thousands of ions emanating from identically prepared control and experimental samples can be made. Using this configuration, we can determine the change in relative abundance of a small number of ions between the two conditions solely by accurate mass and retention time. Employing standard operating procedures for both sample preparation and ESI-mass spectrometry, one typically obtains under 5 ppm mass precision and quantitative variations between 10 and 15%. The principal focus of this paper will demonstrate the quantitative aspects of the methodology and continue with a discussion of the associated, complementary qualitative capabilities.

  1. Accurate structures and binding energies for small water clusters: The water trimer

    SciTech Connect

    Nielsen, I.M.; Seidl, E.T.; Janssen, C.L.

    1999-05-01

    The global minimum on the water trimer potential energy surface has been investigated by means of second-order Mo/ller-Plesset (MP2) perturbation theory employing the series of correlation-consistent basis sets aug-cc-pVXZ (X = D, T, Q, 5, 6), the largest of which contains 1329 basis functions. Definitive predictions are made for the binding energy and equilibrium structure, and improved values are presented for the harmonic vibrational frequencies. A value of 15.82{plus_minus}0.05 kcal mol{sup {minus}1} is advanced for the infinite basis set frozen core MP2 binding energy, obtained by extrapolation of MP2 correlation energies computed at the aug-cc-pVQZ MP2 geometry. Inclusion of core correlation, using the aug-cc-pCV5Z basis set, has been found to increase the binding energy by 0.08 kcal mol{sup {minus}1}, and after consideration of core correlation and higher-order correlation effects, the classical binding energy for the water trimer is estimated to be 15.9{plus_minus}0.2 kcal mol{sup {minus}1}. A zero-point vibrational correction of {minus}5.43 kcal mol{sup {minus}1} has been computed from aug-cc-pVTZ MP2 harmonic vibrational frequencies. The accuracy of different computational schemes for obtaining the binding energies of the water dimer and trimer has been investigated, and computationally feasible methods are suggested for obtaining accurate structures and binding energies for larger water clusters.{copyright} {ital 1999 American Institute of Physics.}

  2. Accurate calculation of conformational free energy differences in explicit water: the confinement-solvation free energy approach.

    PubMed

    Esque, Jeremy; Cecchini, Marco

    2015-04-23

    The calculation of the free energy of conformation is key to understanding the function of biomolecules and has attracted significant interest in recent years. Here, we present an improvement of the confinement method that was designed for use in the context of explicit solvent MD simulations. The development involves an additional step in which the solvation free energy of the harmonically restrained conformers is accurately determined by multistage free energy perturbation simulations. As a test-case application, the newly introduced confinement/solvation free energy (CSF) approach was used to compute differences in free energy between conformers of the alanine dipeptide in explicit water. The results are in excellent agreement with reference calculations based on both converged molecular dynamics and umbrella sampling. To illustrate the general applicability of the method, conformational equilibria of met-enkephalin (5 aa) and deca-alanine (10 aa) in solution were also analyzed. In both cases, smoothly converged free-energy results were obtained in agreement with equilibrium sampling or literature calculations. These results demonstrate that the CSF method may provide conformational free-energy differences of biomolecules with small statistical errors (below 0.5 kcal/mol) and at a moderate computational cost even with a full representation of the solvent.

  3. Accurate potential energy, dipole moment curves, and lifetimes of vibrational states of heteronuclear alkali dimers

    SciTech Connect

    Fedorov, Dmitry A.; Varganov, Sergey A.; Derevianko, Andrei

    2014-05-14

    We calculate the potential energy curves, the permanent dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X{sup 1}Σ{sup +} electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-ζ basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-ζ quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of permanent dipole moments. The dissociation energies are overestimated by only 14 cm{sup −1} for LiNa and by no more than 114 cm{sup −1} for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm{sup −1}, and the discrepancies for the anharmonic correction are less than 0.1 cm{sup −1}. We show that correlation between atomic electronegativity differences and permanent dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schrödinger equation is solved with the B-spline basis set method. The transition dipole moments between all vibrational states, the Einstein coefficients, and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.

  4. Accurate potential energy, dipole moment curves, and lifetimes of vibrational states of heteronuclear alkali dimers.

    PubMed

    Fedorov, Dmitry A; Derevianko, Andrei; Varganov, Sergey A

    2014-05-14

    We calculate the potential energy curves, the permanent dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X(1)Σ(+) electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-ζ basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-ζ quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of permanent dipole moments. The dissociation energies are overestimated by only 14 cm(-1) for LiNa and by no more than 114 cm(-1) for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm(-1), and the discrepancies for the anharmonic correction are less than 0.1 cm(-1). We show that correlation between atomic electronegativity differences and permanent dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schrödinger equation is solved with the B-spline basis set method. The transition dipole moments between all vibrational states, the Einstein coefficients, and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.

  5. Energy expenditure during level human walking: seeking a simple and accurate predictive solution.

    PubMed

    Ludlow, Lindsay W; Weyand, Peter G

    2016-03-01

    Accurate prediction of the metabolic energy that walking requires can inform numerous health, bodily status, and fitness outcomes. We adopted a two-step approach to identifying a concise, generalized equation for predicting level human walking metabolism. Using literature-aggregated values we compared 1) the predictive accuracy of three literature equations: American College of Sports Medicine (ACSM), Pandolf et al., and Height-Weight-Speed (HWS); and 2) the goodness-of-fit possible from one- vs. two-component descriptions of walking metabolism. Literature metabolic rate values (n = 127; speed range = 0.4 to 1.9 m/s) were aggregated from 25 subject populations (n = 5-42) whose means spanned a 1.8-fold range of heights and a 4.2-fold range of weights. Population-specific resting metabolic rates (V̇o2 rest) were determined using standardized equations. Our first finding was that the ACSM and Pandolf et al. equations underpredicted nearly all 127 literature-aggregated values. Consequently, their standard errors of estimate (SEE) were nearly four times greater than those of the HWS equation (4.51 and 4.39 vs. 1.13 ml O2·kg(-1)·min(-1), respectively). For our second comparison, empirical best-fit relationships for walking metabolism were derived from the data set in one- and two-component forms for three V̇o2-speed model types: linear (∝V(1.0)), exponential (∝V(2.0)), and exponential/height (∝V(2.0)/Ht). We found that the proportion of variance (R(2)) accounted for, when averaged across the three model types, was substantially lower for one- vs. two-component versions (0.63 ± 0.1 vs. 0.90 ± 0.03) and the predictive errors were nearly twice as great (SEE = 2.22 vs. 1.21 ml O2·kg(-1)·min(-1)). Our final analysis identified the following concise, generalized equation for predicting level human walking metabolism: V̇o2 total = V̇o2 rest + 3.85 + 5.97·V(2)/Ht (where V is measured in m/s, Ht in meters, and V̇o2 in ml O2·kg(-1)·min(-1)).

  6. Accurate feature detection and estimation using nonlinear and multiresolution analysis

    NASA Astrophysics Data System (ADS)

    Rudin, Leonid; Osher, Stanley

    1994-11-01

    A program for feature detection and estimation using nonlinear and multiscale analysis was completed. The state-of-the-art edge detection was combined with multiscale restoration (as suggested by the first author) and robust results in the presence of noise were obtained. Successful applications to numerous images of interest to DOD were made. Also, a new market in the criminal justice field was developed, based in part, on this work.

  7. Conformational energy range of ligands in protein crystal structures: The difficult quest for accurate understanding.

    PubMed

    Peach, Megan L; Cachau, Raul E; Nicklaus, Marc C

    2017-02-24

    In this review, we address a fundamental question: What is the range of conformational energies seen in ligands in protein-ligand crystal structures? This value is important biophysically, for better understanding the protein-ligand binding process; and practically, for providing a parameter to be used in many computational drug design methods such as docking and pharmacophore searches. We synthesize a selection of previously reported conflicting results from computational studies of this issue and conclude that high ligand conformational energies really are present in some crystal structures. The main source of disagreement between different analyses appears to be due to divergent treatments of electrostatics and solvation. At the same time, however, for many ligands, a high conformational energy is in error, due to either crystal structure inaccuracies or incorrect determination of the reference state. Aside from simple chemistry mistakes, we argue that crystal structure error may mainly be because of the heuristic weighting of ligand stereochemical restraints relative to the fit of the structure to the electron density. This problem cannot be fixed with improvements to electron density fitting or with simple ligand geometry checks, though better metrics are needed for evaluating ligand and binding site chemistry in addition to geometry during structure refinement. The ultimate solution for accurately determining ligand conformational energies lies in ultrahigh-resolution crystal structures that can be refined without restraints.

  8. Hydration free energies of cyanide and hydroxide ions from molecular dynamics simulations with accurate force fields

    USGS Publications Warehouse

    Lee, M.W.; Meuwly, M.

    2013-01-01

    The evaluation of hydration free energies is a sensitive test to assess force fields used in atomistic simulations. We showed recently that the vibrational relaxation times, 1D- and 2D-infrared spectroscopies for CN(-) in water can be quantitatively described from molecular dynamics (MD) simulations with multipolar force fields and slightly enlarged van der Waals radii for the C- and N-atoms. To validate such an approach, the present work investigates the solvation free energy of cyanide in water using MD simulations with accurate multipolar electrostatics. It is found that larger van der Waals radii are indeed necessary to obtain results close to the experimental values when a multipolar force field is used. For CN(-), the van der Waals ranges refined in our previous work yield hydration free energy between -72.0 and -77.2 kcal mol(-1), which is in excellent agreement with the experimental data. In addition to the cyanide ion, we also study the hydroxide ion to show that the method used here is readily applicable to similar systems. Hydration free energies are found to sensitively depend on the intermolecular interactions, while bonded interactions are less important, as expected. We also investigate in the present work the possibility of applying the multipolar force field in scoring trajectories generated using computationally inexpensive methods, which should be useful in broader parametrization studies with reduced computational resources, as scoring is much faster than the generation of the trajectories.

  9. Reduction procedures for accurate analysis of MSX surveillance experiment data

    NASA Technical Reports Server (NTRS)

    Gaposchkin, E. Mike; Lane, Mark T.; Abbot, Rick I.

    1994-01-01

    Technical challenges of the Midcourse Space Experiment (MSX) science instruments require careful characterization and calibration of these sensors for analysis of surveillance experiment data. Procedures for reduction of Resident Space Object (RSO) detections will be presented which include refinement and calibration of the metric and radiometric (and photometric) data and calculation of a precise MSX ephemeris. Examples will be given which support the reduction, and these are taken from ground-test data similar in characteristics to the MSX sensors and from the IRAS satellite RSO detections. Examples to demonstrate the calculation of a precise ephemeris will be provided from satellites in similar orbits which are equipped with S-band transponders.

  10. Accurate potential energy surfaces with a DFT+U(R) approach.

    PubMed

    Kulik, Heather J; Marzari, Nicola

    2011-11-21

    We introduce an improvement to the Hubbard U augmented density functional approach known as DFT+U that incorporates variations in the value of self-consistently calculated, linear-response U with changes in geometry. This approach overcomes the one major shortcoming of previous DFT+U studies, i.e., the use of an averaged Hubbard U when comparing energies for different points along a potential energy surface is no longer required. While DFT+U is quite successful at providing accurate descriptions of localized electrons (e.g., d or f) by correcting self-interaction errors of standard exchange correlation functionals, we show several diatomic molecule examples where this position-dependent DFT+U(R) provides a significant two- to four-fold improvement over DFT+U predictions, when compared to accurate correlated quantum chemistry and experimental references. DFT+U(R) reduces errors in binding energies, frequencies, and equilibrium bond lengths by applying the linear-response, position-dependent U(R) at each configuration considered. This extension is most relevant where variations in U are large across the points being compared, as is the case with covalent diatomic molecules such as transition-metal oxides. We thus provide a tool for deciding whether a standard DFT+U approach is sufficient by determining the strength of the dependence of U on changes in coordinates. We also apply this approach to larger systems with greater degrees of freedom and demonstrate how DFT+U(R) may be applied automatically in relaxations, transition-state finding methods, and dynamics.

  11. Accurate, precise, and efficient theoretical methods to calculate anion-π interaction energies in model structures.

    PubMed

    Mezei, Pál D; Csonka, Gábor I; Ruzsinszky, Adrienn; Sun, Jianwei

    2015-01-13

    A correct description of the anion-π interaction is essential for the design of selective anion receptors and channels and important for advances in the field of supramolecular chemistry. However, it is challenging to do accurate, precise, and efficient calculations of this interaction, which are lacking in the literature. In this article, by testing sets of 20 binary anion-π complexes of fluoride, chloride, bromide, nitrate, or carbonate ions with hexafluorobenzene, 1,3,5-trifluorobenzene, 2,4,6-trifluoro-1,3,5-triazine, or 1,3,5-triazine and 30 ternary π-anion-π' sandwich complexes composed from the same monomers, we suggest domain-based local-pair natural orbital coupled cluster energies extrapolated to the complete basis-set limit as reference values. We give a detailed explanation of the origin of anion-π interactions, using the permanent quadrupole moments, static dipole polarizabilities, and electrostatic potential maps. We use symmetry-adapted perturbation theory (SAPT) to calculate the components of the anion-π interaction energies. We examine the performance of the direct random phase approximation (dRPA), the second-order screened exchange (SOSEX), local-pair natural-orbital (LPNO) coupled electron pair approximation (CEPA), and several dispersion-corrected density functionals (including generalized gradient approximation (GGA), meta-GGA, and double hybrid density functional). The LPNO-CEPA/1 results show the best agreement with the reference results. The dRPA method is only slightly less accurate and precise than the LPNO-CEPA/1, but it is considerably more efficient (6-17 times faster) for the binary complexes studied in this paper. For 30 ternary π-anion-π' sandwich complexes, we give dRPA interaction energies as reference values. The double hybrid functionals are much more efficient but less accurate and precise than dRPA. The dispersion-corrected double hybrid PWPB95-D3(BJ) and B2PLYP-D3(BJ) functionals perform better than the GGA and meta

  12. Toward accurate prediction of pKa values for internal protein residues: the importance of conformational relaxation and desolvation energy.

    PubMed

    Wallace, Jason A; Wang, Yuhang; Shi, Chuanyin; Pastoor, Kevin J; Nguyen, Bao-Linh; Xia, Kai; Shen, Jana K

    2011-12-01

    Proton uptake or release controls many important biological processes, such as energy transduction, virus replication, and catalysis. Accurate pK(a) prediction informs about proton pathways, thereby revealing detailed acid-base mechanisms. Physics-based methods in the framework of molecular dynamics simulations not only offer pK(a) predictions but also inform about the physical origins of pK(a) shifts and provide details of ionization-induced conformational relaxation and large-scale transitions. One such method is the recently developed continuous constant pH molecular dynamics (CPHMD) method, which has been shown to be an accurate and robust pK(a) prediction tool for naturally occurring titratable residues. To further examine the accuracy and limitations of CPHMD, we blindly predicted the pK(a) values for 87 titratable residues introduced in various hydrophobic regions of staphylococcal nuclease and variants. The predictions gave a root-mean-square deviation of 1.69 pK units from experiment, and there were only two pK(a)'s with errors greater than 3.5 pK units. Analysis of the conformational fluctuation of titrating side-chains in the context of the errors of calculated pK(a) values indicate that explicit treatment of conformational flexibility and the associated dielectric relaxation gives CPHMD a distinct advantage. Analysis of the sources of errors suggests that more accurate pK(a) predictions can be obtained for the most deeply buried residues by improving the accuracy in calculating desolvation energies. Furthermore, it is found that the generalized Born implicit-solvent model underlying the current CPHMD implementation slightly distorts the local conformational environment such that the inclusion of an explicit-solvent representation may offer improvement of accuracy.

  13. SCAN: An Efficient Density Functional Yielding Accurate Structures and Energies of Diversely-Bonded Materials

    NASA Astrophysics Data System (ADS)

    Sun, Jianwei

    The accuracy and computational efficiency of the widely used Kohn-Sham density functional theory (DFT) are limited by the approximation to its exchange-correlation energy Exc. The earliest local density approximation (LDA) overestimates the strengths of all bonds near equilibrium (even the vdW bonds). By adding the electron density gradient to model Exc, generalized gradient approximations (GGAs) generally soften the bonds to give robust and overall more accurate descriptions, except for the vdW interaction which is largely lost. Further improvement for covalent, ionic, and hydrogen bonds can be obtained by the computationally more expensive hybrid GGAs, which mix GGAs with the nonlocal exact exchange. Meta-GGAs are still semilocal in computation and thus efficient. Compared to GGAs, they add the kinetic energy density that enables them to recognize and accordingly treat different bonds, which no LDA or GGA can. We show here that the recently developed non-empirical strongly constrained and appropriately normed (SCAN) meta-GGA improves significantly over LDA and the standard Perdew-Burke-Ernzerhof GGA for geometries and energies of diversely-bonded materials (including covalent, metallic, ionic, hydrogen, and vdW bonds) at comparable efficiency. Often SCAN matches or improves upon the accuracy of a hybrid functional, at almost-GGA cost. This work has been supported by NSF under DMR-1305135 and CNS-09-58854, and by DOE BES EFRC CCDM under DE-SC0012575.

  14. Communication: An accurate global potential energy surface for the ground electronic state of ozone

    SciTech Connect

    Dawes, Richard E-mail: hguo@unm.edu; Lolur, Phalgun; Li, Anyang; Jiang, Bin; Guo, Hua E-mail: hguo@unm.edu

    2013-11-28

    We report a new full-dimensional and global potential energy surface (PES) for the O + O{sub 2} → O{sub 3} ozone forming reaction based on explicitly correlated multireference configuration interaction (MRCI-F12) data. It extends our previous [R. Dawes, P. Lolur, J. Ma, and H. Guo, J. Chem. Phys. 135, 081102 (2011)] dynamically weighted multistate MRCI calculations of the asymptotic region which showed the widely found submerged reef along the minimum energy path to be the spurious result of an avoided crossing with an excited state. A spin-orbit correction was added and the PES tends asymptotically to the recently developed long-range electrostatic model of Lepers et al. [J. Chem. Phys. 137, 234305 (2012)]. This PES features: (1) excellent equilibrium structural parameters, (2) good agreement with experimental vibrational levels, (3) accurate dissociation energy, and (4) most-notably, a transition region without a spurious reef. The new PES is expected to allow insight into the still unresolved issues surrounding the kinetics, dynamics, and isotope signature of ozone.

  15. Accurate Cross-section Calculations for Low-Energy Electron-Atom Collisions

    SciTech Connect

    Zatsarinny, Oleg; Bartschat, Klaus

    2011-05-11

    We describe a recently developed fully relativistic B-spline R-matrix method for atomic structure as well as calculations for electron and photon collision with atoms and ions. The method is based on the solution of the many-electron Fock-Dirac equation and allows to employ non-orthogonal sets of atomic orbitals. A B-spline basis is used to generate both the target description and the R-matrix basis functions in the inner region. Employing B-splines of different orders for the large and small components prevents the appearance of spurious states in the spectrum of the Dirac equation. Using term-dependent and thus nonorthogonal sets of one-electron functions enables us to generate accurate and flexible representations of the target states and the scattering function. Our method is based upon the Dirac-Coulomb Hamiltonian and thus may be employed for any complex atom or ion, without the use of phenomenological core potentials. Example results from recent applications of the method for accurate calculations of low-energy electron scattering from noble gases are presented. In most cases we obtained a substantial improvement over results obtained in previous Breit-Pauli R-matrix calculations.

  16. Accurate first-principles structures and energies of diversely bonded systems from an efficient density functional

    NASA Astrophysics Data System (ADS)

    Sun, Jianwei; Remsing, Richard C.; Zhang, Yubo; Sun, Zhaoru; Ruzsinszky, Adrienn; Peng, Haowei; Yang, Zenghui; Paul, Arpita; Waghmare, Umesh; Wu, Xifan; Klein, Michael L.; Perdew, John P.

    2016-09-01

    One atom or molecule binds to another through various types of bond, the strengths of which range from several meV to several eV. Although some computational methods can provide accurate descriptions of all bond types, those methods are not efficient enough for many studies (for example, large systems, ab initio molecular dynamics and high-throughput searches for functional materials). Here, we show that the recently developed non-empirical strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) within the density functional theory framework predicts accurate geometries and energies of diversely bonded molecules and materials (including covalent, metallic, ionic, hydrogen and van der Waals bonds). This represents a significant improvement at comparable efficiency over its predecessors, the GGAs that currently dominate materials computation. Often, SCAN matches or improves on the accuracy of a computationally expensive hybrid functional, at almost-GGA cost. SCAN is therefore expected to have a broad impact on chemistry and materials science.

  17. Screened exchange hybrid density functional for accurate and efficient structures and interaction energies.

    PubMed

    Brandenburg, Jan Gerit; Caldeweyher, Eike; Grimme, Stefan

    2016-06-21

    We extend the recently introduced PBEh-3c global hybrid density functional [S. Grimme et al., J. Chem. Phys., 2015, 143, 054107] by a screened Fock exchange variant based on the Henderson-Janesko-Scuseria exchange hole model. While the excellent performance of the global hybrid is maintained for small covalently bound molecules, its performance for computed condensed phase mass densities is further improved. Most importantly, a speed up of 30 to 50% can be achieved and especially for small orbital energy gap cases, the method is numerically much more robust. The latter point is important for many applications, e.g., for metal-organic frameworks, organic semiconductors, or protein structures. This enables an accurate density functional based electronic structure calculation of a full DNA helix structure on a single core desktop computer which is presented as an example in addition to comprehensive benchmark results.

  18. Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces

    NASA Astrophysics Data System (ADS)

    Mead, A. J.; Heymans, C.; Lombriser, L.; Peacock, J. A.; Steele, O. I.; Winther, H. A.

    2016-06-01

    We present an accurate non-linear matter power spectrum prediction scheme for a variety of extensions to the standard cosmological paradigm, which uses the tuned halo model previously developed in Mead et al. We consider dark energy models that are both minimally and non-minimally coupled, massive neutrinos and modified gravitational forces with chameleon and Vainshtein screening mechanisms. In all cases, we compare halo-model power spectra to measurements from high-resolution simulations. We show that the tuned halo-model method can predict the non-linear matter power spectrum measured from simulations of parametrized w(a) dark energy models at the few per cent level for k < 10 h Mpc-1, and we present theoretically motivated extensions to cover non-minimally coupled scalar fields, massive neutrinos and Vainshtein screened modified gravity models that result in few per cent accurate power spectra for k < 10 h Mpc-1. For chameleon screened models, we achieve only 10 per cent accuracy for the same range of scales. Finally, we use our halo model to investigate degeneracies between different extensions to the standard cosmological model, finding that the impact of baryonic feedback on the non-linear matter power spectrum can be considered independently of modified gravity or massive neutrino extensions. In contrast, considering the impact of modified gravity and massive neutrinos independently results in biased estimates of power at the level of 5 per cent at scales k > 0.5 h Mpc-1. An updated version of our publicly available HMCODE can be found at https://github.com/alexander-mead/hmcode.

  19. An approach to an accurate determination of the energy spectrum of high-energy electron beams using magnetic spectrometry

    NASA Astrophysics Data System (ADS)

    Renner, F.; Schwab, A.; Kapsch, R.-P.; Makowski, Ch; Jannek, D.

    2014-03-01

    At the national metrology institute of Germany, the Physikalisch-Technische Bundesanstalt, a research accelerator for dosimetry in radiation therapy has been installed. Magnetic spectrometry is used to determine the spectrum of high-energy electrons generated by this accelerator. Regarding the intended experiments at the accelerator, a high accuracy for the energy determination of the electron beam is required. For this purpose, an experimental setup is used that has a number of additional devices assembled around the spectrometer to determine geometric characteristics of the electron beam, which influence the energy analysis. For the analysis of the acquired data, a software was developed which meets specific needs. One important aspect is that the software is based on an algorithm for energy determination which considers the measured magnetic flux density of the spectrometer and geometric details of the beam and the spectrometer. The software also meets the demand that it can be used to estimate the uncertainty assigned to the energy. This paper covers the experimental and analytical background of magnetic spectrometry at the high-energy beamline of PTB's research accelerator. A comparison of results calculated with the specific algorithm for energy determination which was developed for this experimental setup and with well-known algorithms is given to show the advantage of the specific method. Results of measurements and their analysis with the algorithm are presented as well.

  20. Accurate ab initio potential energy computations for the H sub 4 system: Tests of some analytic potential energy surfaces

    SciTech Connect

    Boothroyd, A.I. ); Dove, J.E.; Keogh, W.J. ); Martin, P.G. ); Peterson, M.R. )

    1991-09-15

    The interaction potential energy surface (PES) of H{sub 4} is of great importance for quantum chemistry, as a test case for molecule--molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H{sub 2} in molecular clouds, at densities too low to be accessible experimentally. Accurate {ital ab} {ital initio} energies were computed for 6046 conformations of H{sub 4}, using a multiple reference (single and) double excitation configuration interaction (MRD-CI) program. Both systematic and random'' errors were estimated to have an rms size of 0.6 mhartree, for a total rms error of about 0.9 mhartree (or 0.55 kcal/mol) in the final {ital ab} {ital initio} energy values. It proved possible to include in a self-consistent way {ital ab} {ital initio} energies calculated by Schwenke, bringing the number of H{sub 4} conformations to 6101. {ital Ab} {ital initio} energies were also computed for 404 conformations of H{sub 3}; adding {ital ab} {ital initio} energies calculated by other authors yielded a total of 772 conformations of H{sub 3}. (The H{sub 3} results, and an improved analytic PES for H{sub 3}, are reported elsewhere.) {ital Ab} {ital initio} energies are tabulated in this paper only for a sample of H{sub 4} conformations; a full list of all 6101 conformations of H{sub 4} (and 772 conformations of H{sub 3} ) is available from Physics Auxiliary Publication Service (PAPS), or from the authors.

  1. Statistical Energy Analysis Program

    NASA Technical Reports Server (NTRS)

    Ferebee, R. C.; Trudell, R. W.; Yano, L. I.; Nygaard, S. I.

    1985-01-01

    Statistical Energy Analysis (SEA) is powerful tool for estimating highfrequency vibration spectra of complex structural systems and incorporated into computer program. Basic SEA analysis procedure divided into three steps: Idealization, parameter generation, and problem solution. SEA computer program written in FORTRAN V for batch execution.

  2. Charged Point Defects in the Flatland: Accurate Formation Energy Calculations in Two-Dimensional Materials

    NASA Astrophysics Data System (ADS)

    Komsa, Hannu-Pekka; Berseneva, Natalia; Krasheninnikov, Arkady V.; Nieminen, Risto M.

    2014-07-01

    Impurities and defects frequently govern materials properties, with the most prominent example being the doping of bulk semiconductors where a minute amount of foreign atoms can be responsible for the operation of the electronic devices. Several computational schemes based on a supercell approach have been developed to get insights into types and equilibrium concentrations of point defects, which successfully work in bulk materials. Here, we show that many of these schemes cannot directly be applied to two-dimensional (2D) systems, as formation energies of charged point defects are dominated by large spurious electrostatic interactions between defects in inhomogeneous environments. We suggest two approaches that solve this problem and give accurate formation energies of charged defects in 2D systems in the dilute limit. Our methods, which are applicable to all kinds of charged defects in any 2D system, are benchmarked for impurities in technologically important h-BN and MoS2 2D materials, and they are found to perform equally well for substitutional and adatom impurities.

  3. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    SciTech Connect

    Thompson, A.P.; Swiler, L.P.; Trott, C.R.; Foiles, S.M.; Tucker, G.J.

    2015-03-15

    We present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum.

  4. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    NASA Astrophysics Data System (ADS)

    Thompson, A. P.; Swiler, L. P.; Trott, C. R.; Foiles, S. M.; Tucker, G. J.

    2015-03-01

    We present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum.

  5. Anharmonic zero point vibrational energies: Tipping the scales in accurate thermochemistry calculations?

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Florian; Rauhut, Guntram; Feller, David; Peterson, Kirk A.

    2013-01-01

    Anharmonic zero point vibrational energies (ZPVEs) calculated using both conventional CCSD(T) and MP2 in combination with vibrational second-order perturbation theory (VPT2) are compared to explicitly correlated CCSD(T)-F12 and MP2-F12 results that utilize vibrational configuration interaction (VCI) theory for 26 molecules of varying size. Sequences of correlation consistent basis sets are used throughout. It is found that the explicitly correlated methods yield results close to the basis set limit even with double-zeta quality basis sets. In particular, the anharmonic contributions to the ZPVE are accurately recovered at just the MP2 (or MP2-F12) level of theory. Somewhat surprisingly, the best vibrational CI results agreed with the VPT2 values with a mean unsigned deviation of just 0.09 kJ/mol and a standard deviation of just 0.11 kJ/mol. The largest difference was observed for C4H4O (0.34 kJ/mol). A simplified version of the vibrational CI procedure that limited the modal expansion to at most 2-mode coupling yielded anharmonic corrections generally within about 0.1 kJ/mol of the full 3- or 4-mode results, except in the cases of C3H8 and C4H4O where the contributions were underestimated by 1.3 and 0.8 kJ/mol, respectively (34% and 40%, respectively). For the molecules considered in this work, accurate anharmonic ZPVEs are most economically obtained by combining CCSD(T)-F12a/cc-pVDZ-F12 harmonic frequencies with either MP2/aug-cc-pVTZ/VPT2 or MP2-F12/cc-pVDZ-F12/VCI anharmonic corrections.

  6. No Galaxy Left Behind: Accurate Measurements with the Faintest Objects in the Dark Energy Survey

    SciTech Connect

    Suchyta, E.

    2016-01-27

    Accurate statistical measurement with large imaging surveys has traditionally required throwing away a sizable fraction of the data. This is because most measurements have have relied on selecting nearly complete samples, where variations in the composition of the galaxy population with seeing, depth, or other survey characteristics are small. We introduce a new measurement method that aims to minimize this wastage, allowing precision measurement for any class of stars or galaxies detectable in an imaging survey. We have implemented our proposal in Balrog, a software package which embeds fake objects in real imaging in order to accurately characterize measurement biases. We also demonstrate this technique with an angular clustering measurement using Dark Energy Survey (DES) data. We first show that recovery of our injected galaxies depends on a wide variety of survey characteristics in the same way as the real data. We then construct a flux-limited sample of the faintest galaxies in DES, chosen specifically for their sensitivity to depth and seeing variations. Using the synthetic galaxies as randoms in the standard LandySzalay correlation function estimator suppresses the effects of variable survey selection by at least two orders of magnitude. Now our measured angular clustering is found to be in excellent agreement with that of a matched sample drawn from much deeper, higherresolution space-based COSMOS imaging; over angular scales of 0.004° < θ < 0.2 ° , we find a best-fit scaling amplitude between the DES and COSMOS measurements of 1.00 ± 0.09. We expect this methodology to be broadly useful for extending the statistical reach of measurements in a wide variety of coming imaging surveys.

  7. No galaxy left behind: accurate measurements with the faintest objects in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Suchyta, E.; Huff, E. M.; Aleksić, J.; Melchior, P.; Jouvel, S.; MacCrann, N.; Ross, A. J.; Crocce, M.; Gaztanaga, E.; Honscheid, K.; Leistedt, B.; Peiris, H. V.; Rykoff, E. S.; Sheldon, E.; Abbott, T.; Abdalla, F. B.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; James, D. J.; Jarvis, M.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Miller, C. J.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Nord, B.; Ogando, R.; Percival, W. J.; Reil, K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Vikram, V.; Walker, A. R.; Wechsler, R. H.; Zhang, Y.; DES Collaboration

    2016-03-01

    Accurate statistical measurement with large imaging surveys has traditionally required throwing away a sizable fraction of the data. This is because most measurements have relied on selecting nearly complete samples, where variations in the composition of the galaxy population with seeing, depth, or other survey characteristics are small. We introduce a new measurement method that aims to minimize this wastage, allowing precision measurement for any class of detectable stars or galaxies. We have implemented our proposal in BALROG, software which embeds fake objects in real imaging to accurately characterize measurement biases. We demonstrate this technique with an angular clustering measurement using Dark Energy Survey (DES) data. We first show that recovery of our injected galaxies depends on a variety of survey characteristics in the same way as the real data. We then construct a flux-limited sample of the faintest galaxies in DES, chosen specifically for their sensitivity to depth and seeing variations. Using the synthetic galaxies as randoms in the Landy-Szalay estimator suppresses the effects of variable survey selection by at least two orders of magnitude. With this correction, our measured angular clustering is found to be in excellent agreement with that of a matched sample from much deeper, higher resolution space-based Cosmological Evolution Survey (COSMOS) imaging; over angular scales of 0.004° < θ < 0.2°, we find a best-fitting scaling amplitude between the DES and COSMOS measurements of 1.00 ± 0.09. We expect this methodology to be broadly useful for extending measurements' statistical reach in a variety of upcoming imaging surveys.

  8. No Galaxy Left Behind: Accurate Measurements with the Faintest Objects in the Dark Energy Survey

    DOE PAGES

    Suchyta, E.

    2016-01-27

    Accurate statistical measurement with large imaging surveys has traditionally required throwing away a sizable fraction of the data. This is because most measurements have have relied on selecting nearly complete samples, where variations in the composition of the galaxy population with seeing, depth, or other survey characteristics are small. We introduce a new measurement method that aims to minimize this wastage, allowing precision measurement for any class of stars or galaxies detectable in an imaging survey. We have implemented our proposal in Balrog, a software package which embeds fake objects in real imaging in order to accurately characterize measurement biases.more » We also demonstrate this technique with an angular clustering measurement using Dark Energy Survey (DES) data. We first show that recovery of our injected galaxies depends on a wide variety of survey characteristics in the same way as the real data. We then construct a flux-limited sample of the faintest galaxies in DES, chosen specifically for their sensitivity to depth and seeing variations. Using the synthetic galaxies as randoms in the standard LandySzalay correlation function estimator suppresses the effects of variable survey selection by at least two orders of magnitude. Now our measured angular clustering is found to be in excellent agreement with that of a matched sample drawn from much deeper, higherresolution space-based COSMOS imaging; over angular scales of 0.004° < θ < 0.2 ° , we find a best-fit scaling amplitude between the DES and COSMOS measurements of 1.00 ± 0.09. We expect this methodology to be broadly useful for extending the statistical reach of measurements in a wide variety of coming imaging surveys.« less

  9. Building Energy Consumption Analysis

    SciTech Connect

    2005-03-02

    DOE2.1E-121SUNOS is a set of modules for energy analysis in buildings. Modules are included to calculate the heating and cooling loads for each space in a building for each hour of a year (LOADS), to simulate the operation and response of the equipment and systems that control temperature and humidity and distribute heating, cooling and ventilation to the building (SYSTEMS), to model energy conversion equipment that uses fuel or electricity to provide the required heating, cooling and electricity (PLANT), and to compute the cost of energy and building operation based on utility rate schedule and economic parameters (ECONOMICS).

  10. Accurate bond energies of biodiesel methyl esters from multireference averaged coupled-pair functional calculations.

    PubMed

    Oyeyemi, Victor B; Keith, John A; Carter, Emily A

    2014-09-04

    Accurate bond dissociation energies (BDEs) are important for characterizing combustion chemistry, particularly the initial stages of pyrolysis. Here we contribute to evaluating the thermochemistry of biodiesel methyl ester molecules using ab initio BDEs derived from a multireference averaged coupled-pair functional (MRACPF2)-based scheme. Having previously validated this approach for hydrocarbons and a variety of oxygenates, herein we provide further validation for bonds within carboxylic acids and methyl esters, finding our scheme predicts BDEs within chemical accuracy (i.e., within 1 kcal/mol) for these molecules. Insights into BDE trends with ester size are then analyzed for methyl formate through methyl crotonate. We find that the carbonyl group in the ester moiety has only a local effect on BDEs. C═C double bonds in ester alkyl chains are found to increase the strengths of bonds adjacent to the double bond. An important exception are bonds beta to C═C or C═O bonds, which produce allylic-like radicals upon dissociation. The observed trends arise from different degrees of geometric relaxation and resonance stabilization in the radicals produced. We also compute BDEs in various small alkanes and alkenes as models for the long hydrocarbon chain of actual biodiesel methyl esters. We again show that allylic bonds in the alkenes are much weaker than those in the small methyl esters, indicating that hydrogen abstractions are more likely at the allylic site and even more likely at bis-allylic sites of alkyl chains due to more electrons involved in π-resonance in the latter. Lastly, we use the BDEs in small surrogates to estimate heretofore unknown BDEs in large methyl esters of biodiesel fuels.

  11. Building Energy Consumption Analysis

    SciTech Connect

    2005-01-24

    DOE2.1E-121 is a set of modules for energy analysis in buildings. Modules are included to calculate the heating and cooling loads for each space in a building for each hour of a year (LOADS), to simulate the operation and response of the equipment and systems that control temperature and humidity and distribute heating, cooling and ventilation to the building (SYSTEMS), to model energy conversion equipment that uses fuel or electricity to provide the required heating, cooling and electricity (PLANT), and to compute the cost of energy and building operation based on utility rate schedule and economic parameters (ECONOMICS). DOE2.1E-121 contains modifications to DOE2.1E which allows 1000 zones to be modeled.

  12. An accurate potential energy curve for helium based on ab initio calculations

    NASA Astrophysics Data System (ADS)

    Janzen, A. R.; Aziz, R. A.

    1997-07-01

    Korona, Williams, Bukowski, Jeziorski, and Szalewicz [J. Chem. Phys. 106, 1 (1997)] constructed a completely ab initio potential for He2 by fitting their calculations using infinite order symmetry adapted perturbation theory at intermediate range, existing Green's function Monte Carlo calculations at short range and accurate dispersion coefficients at long range to a modified Tang-Toennies potential form. The potential with retardation added to the dipole-dipole dispersion is found to predict accurately a large set of microscopic and macroscopic experimental data. The potential with a significantly larger well depth than other recent potentials is judged to be the most accurate characterization of the helium interaction yet proposed.

  13. Accurate Human Tissue Characterization for Energy-Efficient Wireless On-Body Communications

    PubMed Central

    Vallejo, Mónica; Recas, Joaquín; del Valle, Pablo García; Ayala, José L.

    2013-01-01

    The demand for Wireless Body Sensor Networks (WBSNs) is rapidly increasing due to the revolution in wearable systems demonstrated by the penetration of on-the-body sensors in hospitals, sports medicine and general health-care practices. In WBSN, the body acts as a communication channel for the propagation of electromagnetic (EM) waves, where losses are mainly due to absorption of power in the tissue. This paper shows the effects of the dielectric properties of biological tissues in the signal strength and, for the first time, relates these effects with the human body composition. After a careful analysis of results, this work proposes a reactive algorithm for power transmission to alleviate the effect of body movement and body type. This policy achieves up to 40.8% energy savings in a realistic scenario with no performance overhead. PMID:23752565

  14. Accurate human tissue characterization for energy-efficient wireless on-body communications.

    PubMed

    Vallejo, Mónica; Recas, Joaquín; del Valle, Pablo García; Ayala, José L

    2013-06-10

    The demand for Wireless Body Sensor Networks (WBSNs) is rapidly increasing due to the revolution in wearable systems demonstrated by the penetration of on-the-body sensors in hospitals, sports medicine and general health-care practices. In WBSN, the body acts as a communication channel for the propagation of electromagnetic (EM) waves, where losses are mainly due to absorption of power in the tissue. This paper shows the effects of the dielectric properties of biological tissues in the signal strength and, for the first time, relates these effects with the human body composition. After a careful analysis of results, this work proposes a reactive algorithm for power transmission to alleviate the effect of body movement and body type. This policy achieves up to 40.8% energy savings in a realistic scenario with no performance overhead.

  15. Is scintillometer measurement accurate enough for evaluating remote sensing based energy balance ET models?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The three evapotranspiration (ET) measurement/retrieval techniques used in this study, lysimeter, scintillometer and remote sensing vary in their level of complexity, accuracy, resolution and applicability. The lysimeter with its point measurement is the most accurate and direct method to measure ET...

  16. Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for 32S16O2 up to 8000 cm-1

    NASA Astrophysics Data System (ADS)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2014-03-01

    A purely ab initio potential energy surface (PES) was refined with selected 32S16O2 HITRAN data. Compared to HITRAN, the root-mean-squares error (σRMS) for all J = 0-80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm-1. Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296 K and covers up to 8000 cm-1. Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85%-90%. Our predictions for 34S16O2 band origins, higher energy 32S16O2 band origins and missing 32S16O2 IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict 32/34S16O2 band origins below 5500 cm-1 with 0.01-0.03 cm-1 uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The Ka-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO2 IR spectral experimental analysis, as well as elimination of SO2 lines in high-resolution astronomical observations.

  17. Highly Accurate Potential Energy Surface, Dipole Moment Surface, Rovibrational Energy Levels, and Infrared Line List for (32)S(16)O2 up to 8000 cm(exp -1)

    NASA Technical Reports Server (NTRS)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2014-01-01

    A purely ab initio potential energy surface (PES) was refined with selected (32)S(16)O2 HITRAN data. Compared to HITRAN, the root-mean-squares error (RMS) error for all J=0-80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm(exp -1). Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296K and covers up to 8,000 cm(exp -1). Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85-90%. Our predictions for (34)S(16)O2 band origins, higher energy (32)S(16)O2 band origins and missing (32)S(16)O2 IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict (32/34)S(16)O2 band origins below 5500 cm(exp -1) with 0.01-0.03 cm(exp -1) uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The Ka-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO2 IR spectral experimental analysis, as well as elimination of SO2 lines in high-resolution astronomical observations.

  18. Supporting middle school students' development of an accurate and applicable energy concept

    NASA Astrophysics Data System (ADS)

    Nordine, Jeffrey Carl

    Energy is a fundamental unifying concept of science, yet common approaches to energy instruction in middle school have shown little success with helping students develop their naive ideas about energy into more sophisticated understandings that are useful for making sense of their experiences. While traditional approaches to energy focus on performing calculations in idealized systems, our development team produced a new middle school energy unit that focuses qualitatively on the energy transformations that occur in everyday, non-idealized, systems. This approach uses project-based pedagogy to contextualize instruction with the driving question, "How can I use trash to power my stereo?" In this study, I investigate the effectiveness of our approach by tracking 8th grade students' conceptual development during the unit, following up with students who participated in the unit a year previously, and comparing the energy conceptions and content knowledge between energy unit participants and older students in the same school who learned about energy in an approach that did not emphasize energy transformations in non-idealized systems. Results indicate that during instruction, students' energy conceptions progress from a set of disconnected ideas toward a coherent understanding that is organized around the principle of transformation. After instruction, students who participated in the energy unit were generally more capable of using their understanding of energy to make sense of everyday scenarios than were older non-participants. Furthermore, 9th grade students who participated in the energy unit in their 8th grade year continued to develop more sophisticated understandings of energy during their 9th grade biology course. These 9th grade students seemed better prepared to learn about energy content in their biology course than 10th graders, who did not participate in the energy unit, but took the same biology course during their 9th grade year. Overall, my results

  19. The accurate use of impedance analysis for the study of microbial electrochemical systems.

    PubMed

    Dominguez-Benetton, Xochitl; Sevda, Surajbhan; Vanbroekhoven, Karolien; Pant, Deepak

    2012-11-07

    The present critical review aims to portray the principles and theoretical foundations that have been used for the application of electrochemical impedance spectroscopy (EIS) to study electron-transfer mechanisms, mass transfer phenomena and distribution of the heterogeneous properties of microbial electrochemical systems (MXCs). Over the past eight years, the application of this method has allowed major breakthroughs, especially in the field of microbial fuel cells (MFCs); however, it is still most widely extended only to the calculation of internal resistances. The use and interpretation of EIS should greatly improve since the intrinsic knowledge of this field, and efforts and current trends in this field have already allowed its understanding based on rather meaningful physical properties and not only on fitting electrical analogues. From this perspective, the use, analysis and interpretation of EIS applied to the study of MXCs are critically examined. Together with the revision of more than 150 articles directly devoted to this topic, two examples of the correct and improved analysis of EIS data are extensively presented. The first one focuses on the use of graphical methods for improving EIS analysis and the other one concentrates on the elucidation of the constant phase element (CPE) parameters. CPEs have been introduced in equivalent circuit models, sometimes without solid justification or analysis; the effective capacitance has been obtained from CPE parameters, following an unsuitable theory for the case of microbial-electrochemical interfaces. The use of CPE is reviewed in terms of meaningful physical parameters, such as biofilm thickness. The use of a finite-diffusion element is reviewed throughout estimation of accurate values for obtaining the dimensionless numbers, Schmidt and Sherwood, in the context of a dioxygen-reducing-biocathode, under different flow-rate conditions. The use and analysis of EIS in this context are still emerging, but because of

  20. Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method

    SciTech Connect

    Sinha, Debalina; Pavanello, Michele

    2015-08-28

    The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.

  1. Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method.

    PubMed

    Sinha, Debalina; Pavanello, Michele

    2015-08-28

    The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.

  2. One-photon mass-analyzed threshold ionization (MATI) spectroscopy of pyridine: Determination of accurate ionization energy and cationic structure

    NASA Astrophysics Data System (ADS)

    Lee, Yu Ran; Kang, Do Won; Kim, Hong Lae; Kwon, Chan Ho

    2014-11-01

    Ionization energies and cationic structures of pyridine were intensively investigated utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. The present one-photon high-resolution MATI spectrum of pyridine demonstrated a much finer and richer vibrational structure than that of the previously reported two-photon MATI spectrum. From the MATI spectrum and photoionization efficiency curve, the accurate ionization energy of the ionic ground state of pyridine was confidently determined to be 73 570 ± 6 cm-1 (9.1215 ± 0.0007 eV). The observed spectrum was almost completely assigned by utilizing Franck-Condon factors and vibrational frequencies calculated through adjustments of the geometrical parameters of cationic pyridine at the B3LYP/cc-pVTZ level. A unique feature unveiled through rigorous analysis was the prominent progression of the 10 vibrational mode, which corresponds to in-plane ring bending, and the combination of other totally symmetric fundamentals with the ring bending overtones, which contribute to the geometrical change upon ionization. Notably, the remaining peaks originate from the upper electronic state (2A2), as predicted by high-resolution photoelectron spectroscopy studies and symmetry-adapted cluster configuration interaction calculations. Based on the quantitatively good agreement between the experimental and calculated results, it was concluded that upon ionization the pyridine cation in the ground electronic state should have a planar structure of C2v symmetry through the C-N axis.

  3. One-photon mass-analyzed threshold ionization (MATI) spectroscopy of pyridine: Determination of accurate ionization energy and cationic structure

    SciTech Connect

    Lee, Yu Ran; Kang, Do Won; Kim, Hong Lae E-mail: hlkim@kangwon.ac.kr; Kwon, Chan Ho E-mail: hlkim@kangwon.ac.kr

    2014-11-07

    Ionization energies and cationic structures of pyridine were intensively investigated utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. The present one-photon high-resolution MATI spectrum of pyridine demonstrated a much finer and richer vibrational structure than that of the previously reported two-photon MATI spectrum. From the MATI spectrum and photoionization efficiency curve, the accurate ionization energy of the ionic ground state of pyridine was confidently determined to be 73 570 ± 6 cm{sup −1} (9.1215 ± 0.0007 eV). The observed spectrum was almost completely assigned by utilizing Franck-Condon factors and vibrational frequencies calculated through adjustments of the geometrical parameters of cationic pyridine at the B3LYP/cc-pVTZ level. A unique feature unveiled through rigorous analysis was the prominent progression of the 10 vibrational mode, which corresponds to in-plane ring bending, and the combination of other totally symmetric fundamentals with the ring bending overtones, which contribute to the geometrical change upon ionization. Notably, the remaining peaks originate from the upper electronic state ({sup 2}A{sub 2}), as predicted by high-resolution photoelectron spectroscopy studies and symmetry-adapted cluster configuration interaction calculations. Based on the quantitatively good agreement between the experimental and calculated results, it was concluded that upon ionization the pyridine cation in the ground electronic state should have a planar structure of C{sub 2v} symmetry through the C-N axis.

  4. Combining energy and Laplacian regularization to accurately retrieve the depth of brain activity of diffuse optical tomographic data

    NASA Astrophysics Data System (ADS)

    Chiarelli, Antonio M.; Maclin, Edward L.; Low, Kathy A.; Mathewson, Kyle E.; Fabiani, Monica; Gratton, Gabriele

    2016-03-01

    Diffuse optical tomography (DOT) provides data about brain function using surface recordings. Despite recent advancements, an unbiased method for estimating the depth of absorption changes and for providing an accurate three-dimensional (3-D) reconstruction remains elusive. DOT involves solving an ill-posed inverse problem, requiring additional criteria for finding unique solutions. The most commonly used criterion is energy minimization (energy constraint). However, as measurements are taken from only one side of the medium (the scalp) and sensitivity is greater at shallow depths, the energy constraint leads to solutions that tend to be small and superficial. To correct for this bias, we combine the energy constraint with another criterion, minimization of spatial derivatives (Laplacian constraint, also used in low resolution electromagnetic tomography, LORETA). Used in isolation, the Laplacian constraint leads to solutions that tend to be large and deep. Using simulated, phantom, and actual brain activation data, we show that combining these two criteria results in accurate (error <2 mm) absorption depth estimates, while maintaining a two-point spatial resolution of <24 mm up to a depth of 30 mm. This indicates that accurate 3-D reconstruction of brain activity up to 30 mm from the scalp can be obtained with DOT.

  5. Combining energy and Laplacian regularization to accurately retrieve the depth of brain activity of diffuse optical tomographic data.

    PubMed

    Chiarelli, Antonio M; Maclin, Edward L; Low, Kathy A; Mathewson, Kyle E; Fabiani, Monica; Gratton, Gabriele

    2016-03-01

    Diffuse optical tomography (DOT) provides data about brain function using surface recordings. Despite recent advancements, an unbiased method for estimating the depth of absorption changes and for providing an accurate three-dimensional (3-D) reconstruction remains elusive. DOT involves solving an ill-posed inverse problem, requiring additional criteria for finding unique solutions. The most commonly used criterion is energy minimization (energy constraint). However, as measurements are taken from only one side of the medium (the scalp) and sensitivity is greater at shallow depths, the energy constraint leads to solutions that tend to be small and superficial. To correct for this bias, we combine the energy constraint with another criterion, minimization of spatial derivatives (Laplacian constraint, also used in low resolution electromagnetic tomography, LORETA). Used in isolation, the Laplacian constraint leads to solutions that tend to be large and deep. Using simulated, phantom, and actual brain activation data, we show that combining these two criteria results in accurate (error <2 mm) absorption depth estimates, while maintaining a two-point spatial resolution of <24 mm up to a depth of 30 mm. This indicates that accurate 3-D reconstruction of brain activity up to 30 mm from the scalp can be obtained with DOT.

  6. Combining energy and Laplacian regularization to accurately retrieve the depth of brain activity of diffuse optical tomographic data

    PubMed Central

    Chiarelli, Antonio M.; Maclin, Edward L.; Low, Kathy A.; Mathewson, Kyle E.; Fabiani, Monica; Gratton, Gabriele

    2016-01-01

    Abstract. Diffuse optical tomography (DOT) provides data about brain function using surface recordings. Despite recent advancements, an unbiased method for estimating the depth of absorption changes and for providing an accurate three-dimensional (3-D) reconstruction remains elusive. DOT involves solving an ill-posed inverse problem, requiring additional criteria for finding unique solutions. The most commonly used criterion is energy minimization (energy constraint). However, as measurements are taken from only one side of the medium (the scalp) and sensitivity is greater at shallow depths, the energy constraint leads to solutions that tend to be small and superficial. To correct for this bias, we combine the energy constraint with another criterion, minimization of spatial derivatives (Laplacian constraint, also used in low resolution electromagnetic tomography, LORETA). Used in isolation, the Laplacian constraint leads to solutions that tend to be large and deep. Using simulated, phantom, and actual brain activation data, we show that combining these two criteria results in accurate (error <2  mm) absorption depth estimates, while maintaining a two-point spatial resolution of <24  mm up to a depth of 30 mm. This indicates that accurate 3-D reconstruction of brain activity up to 30 mm from the scalp can be obtained with DOT. PMID:26987429

  7. Quantum Dynamics of Vinylidene Photodetachment on an Accurate Global Acetylene-Vinylidene Potential Energy Surface.

    PubMed

    Guo, Lifen; Han, Huixian; Ma, Jianyi; Guo, Hua

    2015-08-06

    Vinylidene is a high-energy isomer of acetylene, and the rearrangement of bonds in the two species serves as a prototype for isomerization reactions. Here, a full-dimensional quantum mechanical study of the vinylidene vibration is carried out on a recently developed global acetylene-vinylidene potential energy surface by simulating the photodetachment dynamics of the vinylidene anion. Several low-lying vibrational levels of the anion were first determined on a new ab initio based potential energy surface, and their photoelectron spectra were obtained within the Condon approximation. The vibrational features of the vinylidene isomer are found to agree well with the experiment in both positions and intensities, validating the global acetylene-vinylidene potential energy surface.

  8. Tools for Accurate and Efficient Analysis of Complex Evolutionary Mechanisms in Microbial Genomes. Final Report

    SciTech Connect

    Nakhleh, Luay

    2014-03-12

    I proposed to develop computationally efficient tools for accurate detection and reconstruction of microbes' complex evolutionary mechanisms, thus enabling rapid and accurate annotation, analysis and understanding of their genomes. To achieve this goal, I proposed to address three aspects. (1) Mathematical modeling. A major challenge facing the accurate detection of HGT is that of distinguishing between these two events on the one hand and other events that have similar "effects." I proposed to develop a novel mathematical approach for distinguishing among these events. Further, I proposed to develop a set of novel optimization criteria for the evolutionary analysis of microbial genomes in the presence of these complex evolutionary events. (2) Algorithm design. In this aspect of the project, I proposed to develop an array of e cient and accurate algorithms for analyzing microbial genomes based on the formulated optimization criteria. Further, I proposed to test the viability of the criteria and the accuracy of the algorithms in an experimental setting using both synthetic as well as biological data. (3) Software development. I proposed the nal outcome to be a suite of software tools which implements the mathematical models as well as the algorithms developed.

  9. Revisiting the blind tests in crystal structure prediction: accurate energy ranking of molecular crystals.

    PubMed

    Asmadi, Aldi; Neumann, Marcus A; Kendrick, John; Girard, Pascale; Perrin, Marc-Antoine; Leusen, Frank J J

    2009-12-24

    In the 2007 blind test of crystal structure prediction hosted by the Cambridge Crystallographic Data Centre (CCDC), a hybrid DFT/MM method correctly ranked each of the four experimental structures as having the lowest lattice energy of all the crystal structures predicted for each molecule. The work presented here further validates this hybrid method by optimizing the crystal structures (experimental and submitted) of the first three CCDC blind tests held in 1999, 2001, and 2004. Except for the crystal structures of compound IX, all structures were reminimized and ranked according to their lattice energies. The hybrid method computes the lattice energy of a crystal structure as the sum of the DFT total energy and a van der Waals (dispersion) energy correction. Considering all four blind tests, the crystal structure with the lowest lattice energy corresponds to the experimentally observed structure for 12 out of 14 molecules. Moreover, good geometrical agreement is observed between the structures determined by the hybrid method and those measured experimentally. In comparison with the correct submissions made by the blind test participants, all hybrid optimized crystal structures (apart from compound II) have the smallest calculated root mean squared deviations from the experimentally observed structures. It is predicted that a new polymorph of compound V exists under pressure.

  10. Size-extensivity-corrected multireference configuration interaction schemes to accurately predict bond dissociation energies of oxygenated hydrocarbons

    SciTech Connect

    Oyeyemi, Victor B.; Krisiloff, David B.; Keith, John A.; Libisch, Florian; Pavone, Michele; Carter, Emily A.

    2014-01-28

    Oxygenated hydrocarbons play important roles in combustion science as renewable fuels and additives, but many details about their combustion chemistry remain poorly understood. Although many methods exist for computing accurate electronic energies of molecules at equilibrium geometries, a consistent description of entire combustion reaction potential energy surfaces (PESs) requires multireference correlated wavefunction theories. Here we use bond dissociation energies (BDEs) as a foundational metric to benchmark methods based on multireference configuration interaction (MRCI) for several classes of oxygenated compounds (alcohols, aldehydes, carboxylic acids, and methyl esters). We compare results from multireference singles and doubles configuration interaction to those utilizing a posteriori and a priori size-extensivity corrections, benchmarked against experiment and coupled cluster theory. We demonstrate that size-extensivity corrections are necessary for chemically accurate BDE predictions even in relatively small molecules and furnish examples of unphysical BDE predictions resulting from using too-small orbital active spaces. We also outline the specific challenges in using MRCI methods for carbonyl-containing compounds. The resulting complete basis set extrapolated, size-extensivity-corrected MRCI scheme produces BDEs generally accurate to within 1 kcal/mol, laying the foundation for this scheme's use on larger molecules and for more complex regions of combustion PESs.

  11. Size-extensivity-corrected multireference configuration interaction schemes to accurately predict bond dissociation energies of oxygenated hydrocarbons

    NASA Astrophysics Data System (ADS)

    Oyeyemi, Victor B.; Krisiloff, David B.; Keith, John A.; Libisch, Florian; Pavone, Michele; Carter, Emily A.

    2014-01-01

    Oxygenated hydrocarbons play important roles in combustion science as renewable fuels and additives, but many details about their combustion chemistry remain poorly understood. Although many methods exist for computing accurate electronic energies of molecules at equilibrium geometries, a consistent description of entire combustion reaction potential energy surfaces (PESs) requires multireference correlated wavefunction theories. Here we use bond dissociation energies (BDEs) as a foundational metric to benchmark methods based on multireference configuration interaction (MRCI) for several classes of oxygenated compounds (alcohols, aldehydes, carboxylic acids, and methyl esters). We compare results from multireference singles and doubles configuration interaction to those utilizing a posteriori and a priori size-extensivity corrections, benchmarked against experiment and coupled cluster theory. We demonstrate that size-extensivity corrections are necessary for chemically accurate BDE predictions even in relatively small molecules and furnish examples of unphysical BDE predictions resulting from using too-small orbital active spaces. We also outline the specific challenges in using MRCI methods for carbonyl-containing compounds. The resulting complete basis set extrapolated, size-extensivity-corrected MRCI scheme produces BDEs generally accurate to within 1 kcal/mol, laying the foundation for this scheme's use on larger molecules and for more complex regions of combustion PESs.

  12. An accurate and efficient method to predict the electronic excitation energies of BODIPY fluorescent dyes.

    PubMed

    Wang, Jia-Nan; Jin, Jun-Ling; Geng, Yun; Sun, Shi-Ling; Xu, Hong-Liang; Lu, Ying-Hua; Su, Zhong-Min

    2013-03-15

    Recently, the extreme learning machine neural network (ELMNN) as a valid computing method has been proposed to predict the nonlinear optical property successfully (Wang et al., J. Comput. Chem. 2012, 33, 231). In this work, first, we follow this line of work to predict the electronic excitation energies using the ELMNN method. Significantly, the root mean square deviation of the predicted electronic excitation energies of 90 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives between the predicted and experimental values has been reduced to 0.13 eV. Second, four groups of molecule descriptors are considered when building the computing models. The results show that the quantum chemical descriptions have the closest intrinsic relation with the electronic excitation energy values. Finally, a user-friendly web server (EEEBPre: Prediction of electronic excitation energies for BODIPY dyes), which is freely accessible to public at the web site: http://202.198.129.218, has been built for prediction. This web server can return the predicted electronic excitation energy values of BODIPY dyes that are high consistent with the experimental values. We hope that this web server would be helpful to theoretical and experimental chemists in related research.

  13. NANA Strategic Energy Plan & Energy Options Analysis

    SciTech Connect

    Jay Hermanson; Brian Yanity

    2008-12-31

    Biomass Feasibility analysis in the upper Kobuk; • Run of the river hydroelectric development for the Upper Kobuk; • Solar photovoltaic (PV) power demonstration projects for Noatak, Ambler, Selawik, Kiana, and Noorvik; • Heat Recovery for several communities; In September 2008, the NRC team participated at the Alaska Rural Energy Conference in Girdwood, Alaska In November 2008, the NRC team gave a presentation on the NANA regional energy plans at a DOE Tribal Energy Program conference in Denver, Colorado. In January 2009, the final SEP report was submitted to NRC.

  14. Reliable Spectroscopic Constants for CCH-, NH2- and Their Isotopomers from an Accurate Potential Energy Function

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Dateo, Christopher E.; Schwenke, David W.; Chaban, Galina M.

    2005-01-01

    Accurate quartic force fields have been determined for the CCH- and NH2- molecular anions using the singles and doubles coupled-cluster method that includes a perturbational estimate of the effects of connected triple excitations, CCSD(T). Very large one-particle basis sets have been used including diffuse functions and up through g-type functions. Correlation of the nitrogen and carbon core electrons has been included, as well as other "small" effects, such as the diagonal Born-Oppenheimer correction, and basis set extrapolation, and corrections for higher-order correlation effects and scalar relativistic effects. Fundamental vibrational frequencies have been computed using standard second-order perturbation theory as well as variational methods. Comparison with the available experimental data is presented and discussed. The implications of our research for the astronomical observation of molecular anions will be discussed.

  15. Revised Charge Equilibration Parameters for More Accurate Hydration Free Energies of Alkanes.

    PubMed

    Davis, Joseph E; Patel, Sandeep

    2010-01-01

    We present a refined alkane charge equilibration (CHEQ) force field, improving our previously reported CHEQ alkane force field[1] to better reproduce experimental hydration free energies. Experimental hydration free energies of ethane, propane, butane, pentane, hexane, and heptane are reproduced to within 3.6% on average. We demonstrate that explicit polarization results in a shift in molecular dipole moment for water molecules associated with the alkane molecule. We also show that our new parameters do not have a significant effect on the alkane-water interactions as measured by the radial distribution function (RDF).

  16. Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

    SciTech Connect

    Han, Huixian; Li, Anyang; Guo, Hua

    2014-12-28

    A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S{sub 0}) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm{sup −1}. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm{sup −1} above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

  17. An accurate global potential energy surface, dipole moment surface, and rovibrational frequencies for NH(3).

    PubMed

    Huang, Xinchuan; Schwenke, David W; Lee, Timothy J

    2008-12-07

    A global potential energy surface (PES) that includes short and long range terms has been determined for the NH(3) molecule. The singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations and the internally contracted averaged coupled-pair functional electronic structure methods have been used in conjunction with very large correlation-consistent basis sets, including diffuse functions. Extrapolation to the one-particle basis set limit was performed and core correlation and scalar relativistic contributions were included directly, while the diagonal Born-Oppenheimer correction was added. Our best purely ab initio PES, denoted "mixed," is constructed from two PESs which differ in whether the ic-ACPF higher-order correlation correction was added or not. Rovibrational transition energies computed from the mixed PES agree well with experiment and the best previous theoretical studies, but most importantly the quality does not deteriorate even up to 10 300 cm(-1) above the zero-point energy (ZPE). The mixed PES was improved further by empirical refinement using the most reliable J=0-2 rovibrational transitions in the HITRAN 2004 database. Agreement between high-resolution experiment and rovibrational transition energies computed from our refined PES for J=0-6 is excellent. Indeed, the root mean square (rms) error for 13 HITRAN 2004 bands for J=0-2 is 0.023 cm(-1) and that for each band is always energies computed with our refined PES should be useful in the assignment of new high-resolution NH(3) spectra and in correcting mistakes in previous assignments. Ideas for further improvements to our refined PES and for extension to other isotopolog are discussed.

  18. Energy-Systems Economic Analysis

    NASA Technical Reports Server (NTRS)

    Doane, J.; Slonski, M. L.; Borden, C. S.

    1982-01-01

    Energy Systems Economic Analysis (ESEA) program is flexible analytical tool for rank ordering of alternative energy systems. Basic ESEA approach derives an estimate of those costs incurred as result of purchasing, installing and operating an energy system. These costs, suitably aggregated into yearly costs over lifetime of system, are divided by expected yearly energy output to determine busbar energy costs. ESEA, developed in 1979, is written in FORTRAN IV for batch execution.

  19. Energy analysis program. 1994 annual report

    SciTech Connect

    Levine, M.D.

    1995-04-01

    This report provides an energy analysis overview. The following topics are described: building energy analysis; urban and energy environmental issues; appliance energy efficiency standards; utility planning and policy; energy efficiency, economics, and policy issues; and international energy and environmental issues.

  20. Accurate double many-body expansion potential energy surface of HS2A2A‧) by scaling the external correlation

    NASA Astrophysics Data System (ADS)

    Lu-Lu, Zhang; Yu-Zhi, Song; Shou-Bao, Gao; Yuan, Zhang; Qing-Tian, Meng

    2016-05-01

    A globally accurate single-sheeted double many-body expansion potential energy surface is reported for the first excited state of HS2 by fitting the accurate ab initio energies, which are calculated at the multireference configuration interaction level with the aug-cc-pVQZ basis set. By using the double many-body expansion-scaled external correlation method, such calculated ab initio energies are then slightly corrected by scaling their dynamical correlation. A grid of 2767 ab initio energies is used in the least-square fitting procedure with the total root-mean square deviation being 1.406 kcal·mol-1. The topographical features of the HS2(A2A‧) global potential energy surface are examined in detail. The attributes of the stationary points are presented and compared with the corresponding ab initio results as well as experimental and other theoretical data, showing good agreement. The resulting potential energy surface of HS2(A2A‧) can be used as a building block for constructing the global potential energy surfaces of larger S/H molecular systems and recommended for dynamic studies on the title molecular system. Project supported by the National Natural Science Foundation of China (Grant No. 11304185), the Taishan Scholar Project of Shandong Province, China, the Shandong Provincial Natural Science Foundation, China (Grant No. ZR2014AM022), the Shandong Province Higher Educational Science and Technology Program, China (Grant No. J15LJ03), the China Postdoctoral Science Foundation (Grant No. 2014M561957), and the Post-doctoral Innovation Project of Shandong Province, China (Grant No. 201402013).

  1. An accurate and efficient computation method of the hydration free energy of a large, complex molecule.

    PubMed

    Yoshidome, Takashi; Ekimoto, Toru; Matubayasi, Nobuyuki; Harano, Yuichi; Kinoshita, Masahiro; Ikeguchi, Mitsunori

    2015-05-07

    The hydration free energy (HFE) is a crucially important physical quantity to discuss various chemical processes in aqueous solutions. Although an explicit-solvent computation with molecular dynamics (MD) simulations is a preferable treatment of the HFE, huge computational load has been inevitable for large, complex solutes like proteins. In the present paper, we propose an efficient computation method for the HFE. In our method, the HFE is computed as a sum of 〈UUV〉/2 (〈UUV〉 is the ensemble average of the sum of pair interaction energy between solute and water molecule) and the water reorganization term mainly reflecting the excluded volume effect. Since 〈UUV〉 can readily be computed through a MD of the system composed of solute and water, an efficient computation of the latter term leads to a reduction of computational load. We demonstrate that the water reorganization term can quantitatively be calculated using the morphometric approach (MA) which expresses the term as the linear combinations of the four geometric measures of a solute and the corresponding coefficients determined with the energy representation (ER) method. Since the MA enables us to finish the computation of the solvent reorganization term in less than 0.1 s once the coefficients are determined, the use of the MA enables us to provide an efficient computation of the HFE even for large, complex solutes. Through the applications, we find that our method has almost the same quantitative performance as the ER method with substantial reduction of the computational load.

  2. Extensive and accurate energy levels and transition rates for Al-like Zn XVIII

    NASA Astrophysics Data System (ADS)

    Si, R.; Zhang, C. Y.; Liu, Y. W.; Chen, Z. B.; Guo, X. L.; Li, S.; Yan, J.; Chen, C. Y.; Wang, K.

    2017-03-01

    Energy levels and transition rates for electric-dipole (E1), electric-quadrupole (E2), magnetic-dipole (M1), and magnetic-quadrupole (M2) transitions of the lowest 393 levels arising from the 3l3 (0 ≤ l ⩽ 2), 3s2 4 l (0 ≤ l ⩽ 3), 3 s 3 p 4 l (0 ≤ l ⩽ 3), 3p2 4 l (0 ≤ l ⩽ 2), 3 s 3 d 4 l (0 ≤ l ⩽ 1), and 3s2 5 l (0 ≤ l ⩽ 4) configurations in Al-like Zn are calculated through the multi-configuration Dirac-Hartree-Fock (MCDHF) method and second-order many-body perturbation theory (MBPT). In the MCDHF calculation, valence-valence and core-valence correlations with the 2 p and 2 s electrons are taken into account. The effect of Breit interaction and quantum electrodynamics corrections on excitation level energies and level lifetimes are assessed though the MCDHF and MBPT calculations. The two sets of level energies are in excellent agreement of better than 0.1%, while the level lifetimes mostly agree to within 2%. Comparisons are also made with experimental measurements and other theoretical results to assess the accuracy of our calculations.

  3. Optimising speed and energy expenditure in accurate visually directed upper limb movements.

    PubMed

    Elliott, Digby; Hansen, Steve; Grierson, Lawrence E M

    2009-04-01

    Traditional models of speed-accuracy relations and limb control are steady-state models that fail to consider the learning history and strategic approach of the performer. Work from this laboratory indicates that a performer adjusts his/her behaviour from trial-to-trial to optimise not only the speed and accuracy of performance, but also energy expenditure. Because some errors have greater temporal and energy costs than others, most performers execute movements that are prepared such that potential errors are of minimal expense. The trajectories and subsequent endpoint distributions of rapid aiming movements depend on advance knowledge about the availability of afferent information for online control, as well as the costs associated with undershooting or overshooting the target position with the initial impulse. With practice, a performer is able to reduce the trial-to-trial variability associated with goal-directed movement through more consistent movement planning processes and more rapid online control. Part of the optimisation process is related to the development of an internal model of performance against which early afferent feedback can be evaluated. This framework for examining speed, accuracy and energy expenditure in goal-directed reaching can be used to help understand the breakdown of efficient limb control due to fatigue, ageing and pathology.

  4. Accurate analysis of planar optical waveguide devices using higher-order FDTD scheme.

    PubMed

    Kong, Fanmin; Li, Kang; Liu, Xin

    2006-11-27

    A higher-order finite-difference time-domain (HO-FDTD) numerical method is proposed for the time-domain analysis of planar optical waveguide devices. The anisotropic perfectly matched layer (APML) absorbing boundary condition for the HO-FDTD scheme is implemented and the numerical dispersion of this scheme is studied. The numerical simulations for the parallel-slab directional coupler are presented and the computing results using this scheme are in highly accordance with analytical solutions. Compared with conventional FDTD method, this scheme can save considerable computational resource without sacrificing solution accuracy and especially could be applied in the accurate analysis of optical devices.

  5. Fast and accurate focusing analysis of large photon sieve using pinhole ring diffraction model.

    PubMed

    Liu, Tao; Zhang, Xin; Wang, Lingjie; Wu, Yanxiong; Zhang, Jizhen; Qu, Hemeng

    2015-06-10

    In this paper, we developed a pinhole ring diffraction model for the focusing analysis of a large photon sieve. Instead of analyzing individual pinholes, we discuss the focusing of all of the pinholes in a single ring. An explicit equation for the diffracted field of individual pinhole ring has been proposed. We investigated the validity range of this generalized model and analytically describe the sufficient conditions for the validity of this pinhole ring diffraction model. A practical example and investigation reveals the high accuracy of the pinhole ring diffraction model. This simulation method could be used for fast and accurate focusing analysis of a large photon sieve.

  6. Accurate radiation temperature and chemical potential from quantitative photoluminescence analysis of hot carrier populations

    NASA Astrophysics Data System (ADS)

    Gibelli, François; Lombez, Laurent; Guillemoles, Jean-François

    2017-02-01

    In order to characterize hot carrier populations in semiconductors, photoluminescence measurement is a convenient tool, enabling us to probe the carrier thermodynamical properties in a contactless way. However, the analysis of the photoluminescence spectra is based on some assumptions which will be discussed in this work. We especially emphasize the importance of the variation of the material absorptivity that should be considered to access accurate thermodynamical properties of the carriers, especially by varying the excitation power. The proposed method enables us to obtain more accurate results of thermodynamical properties by taking into account a rigorous physical description and finds direct application in investigating hot carrier solar cells, which are an adequate concept for achieving high conversion efficiencies with a relatively simple device architecture.

  7. Accurate radiation temperature and chemical potential from quantitative photoluminescence analysis of hot carrier populations.

    PubMed

    Gibelli, François; Lombez, Laurent; Guillemoles, Jean-François

    2017-02-15

    In order to characterize hot carrier populations in semiconductors, photoluminescence measurement is a convenient tool, enabling us to probe the carrier thermodynamical properties in a contactless way. However, the analysis of the photoluminescence spectra is based on some assumptions which will be discussed in this work. We especially emphasize the importance of the variation of the material absorptivity that should be considered to access accurate thermodynamical properties of the carriers, especially by varying the excitation power. The proposed method enables us to obtain more accurate results of thermodynamical properties by taking into account a rigorous physical description and finds direct application in investigating hot carrier solar cells, which are an adequate concept for achieving high conversion efficiencies with a relatively simple device architecture.

  8. Accurate electron affinity of Pb and isotope shifts of binding energies of Pb-

    NASA Astrophysics Data System (ADS)

    Chen, Xiaolin; Ning, Chuangang

    2016-08-01

    Lead (Pb) was the last element of the group IVA whose electron affinity had a low accuracy around 10 meV before the present work. This was due to the generic threshold photodetachment measurement that cannot extent well below 0.5 eV due to the light source limitation. In the present work, the electron affinity of Pb was determined to be 2877.33(13) cm-1 or 0.356 743(16) eV for the isotope m = 208. The accuracy was improved by a factor of 500 with respect to the previous laser photodetachment electron spectroscopy. Moreover, remarkable isotope shifts of the binding energy of Pb- 6p3 4S3/2 - Pb 6p2 3P2 were observed for m = 206, 207, and 208.

  9. Accurate electron affinity of Pb and isotope shifts of binding energies of Pb(.).

    PubMed

    Chen, Xiaolin; Ning, Chuangang

    2016-08-28

    Lead (Pb) was the last element of the group IVA whose electron affinity had a low accuracy around 10 meV before the present work. This was due to the generic threshold photodetachment measurement that cannot extent well below 0.5 eV due to the light source limitation. In the present work, the electron affinity of Pb was determined to be 2877.33(13) cm(-1) or 0.356 743(16) eV for the isotope m = 208. The accuracy was improved by a factor of 500 with respect to the previous laser photodetachment electron spectroscopy. Moreover, remarkable isotope shifts of the binding energy of Pb(-) 6p(3) (4)S3/2 - Pb 6p(2) (3)P2 were observed for m = 206, 207, and 208.

  10. Towards More Accurate Measurements of the Ionization Energy of Molecular Hydrogen

    NASA Astrophysics Data System (ADS)

    Sprecher, D.; Beyer, M.; Liu, J.; Merkt, F.; Salumbides, E.; Eikema, K. S. E.; Ubachs, W.; Jungen, Ch.

    2013-06-01

    With two electrons and two protons, molecular hydrogen is the simplest molecule displaying all features of a chemical bond. H_2 is therefore a fundamental system for testing molecular quantum mechanics and quantum electrodynamics in molecules. The test can be performed by comparing measured and calculated intervals between different rovibronic states of H_2. Two further quantities that can be used for this test are the dissociation and ionization energies of H_2, and considerable efforts have been invested over more than 80 years to improve the precision and accuracy of experimental and theoretical determination of these two quantities. The current status of the comparison is that the theoretical and experimental values of the ionization and dissociation energies of H_2 agree within the combined uncertainty of 30 MHz (see also). The factors currently limiting the precision of the experimental determination will be discussed and the strategies that are being implemented towards overcoming these limitations will be presented. A long-term goal is to achieve a precision of better than 15 kHz, which is the ultimate limit imposed on the accuracy of the theoretical determination by the current uncertainty of the proton-to-electron mass ratio. E. J. Salumbides, G. D. Dickenson, T. I. Ivanov and W. Ubachs, {Phys. Rev. Lett.} 107 (4), 043005 (2011). K. Piszczatowski, G. Lach, M. Przybytek, J. Komasa, K. Pachuckiand and B. Jeziorski, {J. Chem. Theory Comput.} 5 (11), 3039 (2009). J. Liu, E. J. Salumbides, U. Hollenstein, J. C. J. Koelemeij, K. S. E. Eikema, W. Ubachs and F. Merkt, {J. Chem. Phys.} 130 (17), 174306 (2009). D. Sprecher, Ch. Jungen, W. Ubachs and F. Merkt, {Faraday Discuss.} 150, 51 (2011).

  11. Full Dimensional Vibrational Calculations for Methane Using AN Accurate New AB Initio Based Potential Energy Surface

    NASA Astrophysics Data System (ADS)

    Majumder, Moumita; Dawes, Richard; Wang, Xiao-Gang; Carrington, Tucker; Li, Jun; Guo, Hua; Manzhos, Sergei

    2014-06-01

    New potential energy surfaces for methane were constructed, represented as analytic fits to about 100,000 individual high-level ab initio data. Explicitly-correlated multireference data (MRCI-F12(AE)/CVQZ-F12) were computed using Molpro [1] and fit using multiple strategies. Fits with small to negligible errors were obtained using adaptations of the permutation-invariant-polynomials (PIP) approach [2,3] based on neural-networks (PIP-NN) [4,5] and the interpolative moving least squares (IMLS) fitting method [6] (PIP-IMLS). The PESs were used in full-dimensional vibrational calculations with an exact kinetic energy operator by representing the Hamiltonian in a basis of products of contracted bend and stretch functions and using a symmetry adapted Lanczos method to obtain eigenvalues and eigenvectors. Very close agreement with experiment was produced from the purely ab initio PESs. References 1- H.-J. Werner, P. J. Knowles, G. Knizia, 2012.1 ed. 2012, MOLPRO, a package of ab initio programs. see http://www.molpro.net. 2- Z. Xie and J. M. Bowman, J. Chem. Theory Comput 6, 26, 2010. 3- B. J. Braams and J. M. Bowman, Int. Rev. Phys. Chem. 28, 577, 2009. 4- J. Li, B. Jiang and Hua Guo, J. Chem. Phys. 139, 204103 (2013). 5- S Manzhos, X Wang, R Dawes and T Carrington, JPC A 110, 5295 (2006). 6- R. Dawes, X-G Wang, A.W. Jasper and T. Carrington Jr., J. Chem. Phys. 133, 134304 (2010).

  12. Spatial Pattern Classification for More Accurate Forecasting of Variable Energy Resources

    NASA Astrophysics Data System (ADS)

    Novakovskaia, E.; Hayes, C.; Collier, C.

    2014-12-01

    The accuracy of solar and wind forecasts is becoming increasingly essential as grid operators continue to integrate additional renewable generation onto the electric grid. Forecast errors affect rate payers, grid operators, wind and solar plant maintenance crews and energy traders through increases in prices, project down time or lost revenue. While extensive and beneficial efforts were undertaken in recent years to improve physical weather models for a broad spectrum of applications these improvements have generally not been sufficient to meet the accuracy demands of system planners. For renewables, these models are often used in conjunction with additional statistical models utilizing both meteorological observations and the power generation data. Forecast accuracy can be dependent on specific weather regimes for a given location. To account for these dependencies it is important that parameterizations used in statistical models change as the regime changes. An automated tool, based on an artificial neural network model, has been developed to identify different weather regimes as they impact power output forecast accuracy at wind or solar farms. In this study, improvements in forecast accuracy were analyzed for varying time horizons for wind farms and utility-scale PV plants located in different geographical regions.

  13. An atlas of RNA base pairs involving modified nucleobases with optimal geometries and accurate energies.

    PubMed

    Chawla, Mohit; Oliva, Romina; Bujnicki, Janusz M; Cavallo, Luigi

    2015-08-18

    Posttranscriptional modifications greatly enhance the chemical information of RNA molecules, contributing to explain the diversity of their structures and functions. A significant fraction of RNA experimental structures available to date present modified nucleobases, with half of them being involved in H-bonding interactions with other bases, i.e. 'modified base pairs'. Herein we present a systematic investigation of modified base pairs, in the context of experimental RNA structures. To this end, we first compiled an atlas of experimentally observed modified base pairs, for which we recorded occurrences and structural context. Then, for each base pair, we selected a representative for subsequent quantum mechanics calculations, to find out its optimal geometry and interaction energy. Our structural analyses show that most of the modified base pairs are non Watson-Crick like and are involved in RNA tertiary structure motifs. In addition, quantum mechanics calculations quantify and provide a rationale for the impact of the different modifications on the geometry and stability of the base pairs they participate in.

  14. Efficient and accurate evaluation of potential energy matrix elements for quantum dynamics using Gaussian process regression

    NASA Astrophysics Data System (ADS)

    Alborzpour, Jonathan P.; Tew, David P.; Habershon, Scott

    2016-11-01

    Solution of the time-dependent Schrödinger equation using a linear combination of basis functions, such as Gaussian wavepackets (GWPs), requires costly evaluation of integrals over the entire potential energy surface (PES) of the system. The standard approach, motivated by computational tractability for direct dynamics, is to approximate the PES with a second order Taylor expansion, for example centred at each GWP. In this article, we propose an alternative method for approximating PES matrix elements based on PES interpolation using Gaussian process regression (GPR). Our GPR scheme requires only single-point evaluations of the PES at a limited number of configurations in each time-step; the necessity of performing often-expensive evaluations of the Hessian matrix is completely avoided. In applications to 2-, 5-, and 10-dimensional benchmark models describing a tunnelling coordinate coupled non-linearly to a set of harmonic oscillators, we find that our GPR method results in PES matrix elements for which the average error is, in the best case, two orders-of-magnitude smaller and, in the worst case, directly comparable to that determined by any other Taylor expansion method, without requiring additional PES evaluations or Hessian matrices. Given the computational simplicity of GPR, as well as the opportunities for further refinement of the procedure highlighted herein, we argue that our GPR methodology should replace methods for evaluating PES matrix elements using Taylor expansions in quantum dynamics simulations.

  15. Effective approach for accurately calculating individual energy of polar heterojunction interfaces

    NASA Astrophysics Data System (ADS)

    Akiyama, Toru; Nakane, Harunobu; Nakamura, Kohji; Ito, Tomonori

    2016-09-01

    We propose a direct approach for calculating individual energy of polar semiconductor interfaces using density functional theory calculations. This approach is applied to polar interfaces between group-III nitrides (AlN and GaN) and SiC and clarifies the interplay of chemical bonding and charge neutrality at the interface, which is crucial for the stability and polarity of group-III nitrides on SiC substrates. The ideal interface is stabilized among various atomic arrangements over the wide range of the chemical potential on Si-face SiC, whereas those with intermixing are favorable on C-face SiC. The stabilization of the ideal interfaces resulting in Ga-polar GaN and Al-polar AlN films on Si-face SiC is consistent with experiments, suggesting that our approach is versatile to evaluate various polar heterojunction interfaces as well as group-III nitrides on semiconductor substrates.

  16. Energy analysis program, FY 1979

    NASA Astrophysics Data System (ADS)

    1980-04-01

    Energy analysis attempts to understand the volitional choices of energy use and supply available to human society, and the multi-faceted consequences of choosing any one of them. Topics deal with economic impacts; assessments of regional issues and impacts; air quality evaluation; institutional and political issues in California power plant siting; assessment of environmental standards; water issues; characterization of aquatic systems dissolved oxygen profiles; modeling; computer-generated interactive graphics; energy assessment in Hawaii; solar energy in communities; utilities solar financial data; population impacts of geothermal development; energy conservation in colleges and residential sectors; energy policy; decision making; building energy performance standards; standards for residential appliances; and impact of energy performance standards on demand for peak electrical energy.

  17. Nonlinear Aeroelastic Analysis Using a Time-Accurate Navier-Stokes Equations Solver

    NASA Technical Reports Server (NTRS)

    Kuruvila, Geojoe; Bartels, Robert E.; Hong, Moeljo S.; Bhatia, G.

    2007-01-01

    A method to simulate limit cycle oscillation (LCO) due to control surface freeplay using a modified CFL3D, a time-accurate Navier-Stokes computational fluid dynamics (CFD) analysis code with structural modeling capability, is presented. This approach can be used to analyze aeroelastic response of aircraft with structural behavior characterized by nonlinearity in the force verses displacement curve. A limited validation of the method, using very low Mach number experimental data for a three-degrees-of-freedom (pitch/plunge/flap deflection) airfoil model with flap freeplay, is also presented.

  18. Building Energy Monitoring and Analysis

    SciTech Connect

    Hong, Tianzhen; Feng, Wei; Lu, Alison; Xia, Jianjun; Yang, Le; Shen, Qi; Im, Piljae; Bhandari, Mahabir

    2013-06-01

    This project aimed to develop a standard methodology for building energy data definition, collection, presentation, and analysis; apply the developed methods to a standardized energy monitoring platform, including hardware and software, to collect and analyze building energy use data; and compile offline statistical data and online real-time data in both countries for fully understanding the current status of building energy use. This helps decode the driving forces behind the discrepancy of building energy use between the two countries; identify gaps and deficiencies of current building energy monitoring, data collection, and analysis; and create knowledge and tools to collect and analyze good building energy data to provide valuable and actionable information for key stakeholders.

  19. Impact of interfacial high-density water layer on accurate estimation of adsorption free energy by Jarzynski's equality

    NASA Astrophysics Data System (ADS)

    Zhang, Zhisen; Wu, Tao; Wang, Qi; Pan, Haihua; Tang, Ruikang

    2014-01-01

    The interactions between proteins/peptides and materials are crucial to research and development in many biomedical engineering fields. The energetics of such interactions are key in the evaluation of new proteins/peptides and materials. Much research has recently focused on the quality of free energy profiles by Jarzynski's equality, a widely used equation in biosystems. In the present work, considerable discrepancies were observed between the results obtained by Jarzynski's equality and those derived by umbrella sampling in biomaterial-water model systems. Detailed analyses confirm that such discrepancies turn up only when the target molecule moves in the high-density water layer on a material surface. Then a hybrid scheme was adopted based on this observation. The agreement between the results of the hybrid scheme and umbrella sampling confirms the former observation, which indicates an approach to a fast and accurate estimation of adsorption free energy for large biomaterial interfacial systems.

  20. Accurate ab initio predictions of ionization energies and heats of formation for the 2-propyl, phenyl, and benzyl radicals

    NASA Astrophysics Data System (ADS)

    Lau, K.-C.; Ng, C. Y.

    2006-01-01

    The ionization energies (IEs) for the 2-propyl (2-C3H7), phenyl (C6H5), and benzyl (C6H5CH2) radicals have been calculated by the wave-function-based ab initio CCSD(T)/CBS approach, which involves the approximation to the complete basis set (CBS) limit at the coupled cluster level with single and double excitations plus quasiperturbative triple excitation [CCSD(T)]. The zero-point vibrational energy correction, the core-valence electronic correction, and the scalar relativistic effect correction have been also made in these calculations. Although a precise IE value for the 2-C3H7 radical has not been directly determined before due to the poor Franck-Condon factor for the photoionization transition at the ionization threshold, the experimental value deduced indirectly using other known energetic data is found to be in good accord with the present CCSD(T)/CBS prediction. The comparison between the predicted value through the focal-point analysis and the highly precise experimental value for the IE(C6H5CH2) determined in the previous pulsed field ionization photoelectron (PFI-PE) study shows that the CCSD(T)/CBS method is capable of providing an accurate IE prediction for C6H5CH2, achieving an error limit of 35 meV. The benchmarking of the CCSD(T)/CBS IE(C6H5CH2) prediction suggests that the CCSD(T)/CBS IE(C6H5) prediction obtained here has a similar accuracy of 35 meV. Taking into account this error limit for the CCSD(T)/CBS prediction and the experimental uncertainty, the CCSD(T)/CBS IE(C6H5) value is also consistent with the IE(C6H5) reported in the previous HeI photoelectron measurement. Furthermore, the present study provides support for the conclusion that the CCSD(T)/CBS approach with high-level energy corrections can be used to provide reliable IE predictions for C3-C7 hydrocarbon radicals with an uncertainty of +/-35 meV. Employing the atomization scheme, we have also computed the 0 K (298 K) heats of formation in kJ/mol at the CCSD(T)/CBS level for 2-C3H7

  1. Accurate and unambiguous tag-to-gene mapping in serial analysis of gene expression

    PubMed Central

    Malig, Rodrigo; Varela, Cristian; Agosin, Eduardo; Melo, Francisco

    2006-01-01

    Background In this study, we present a robust and reliable computational method for tag-to-gene assignment in serial analysis of gene expression (SAGE). The method relies on current genome information and annotation, incorporation of several new features, and key improvements over alternative methods, all of which are important to determine gene expression levels more accurately. The method provides a complete annotation of potential virtual SAGE tags within a genome, along with an estimation of their confidence for experimental observation that ranks tags that present multiple matches in the genome. Results We applied this method to the Saccharomyces cerevisiae genome, producing the most thorough and accurate annotation of potential virtual SAGE tags that is available today for this organism. The usefulness of this method is exemplified by the significant reduction of ambiguous cases in existing experimental SAGE data. In addition, we report new insights from the analysis of existing SAGE data. First, we found that experimental SAGE tags mapping onto introns, intron-exon boundaries, and non-coding RNA elements are observed in all available SAGE data. Second, a significant fraction of experimental SAGE tags was found to map onto genomic regions currently annotated as intergenic. Third, a significant number of existing experimental SAGE tags for yeast has been derived from truncated cDNAs, which are synthesized through oligo-d(T) priming to internal poly-(A) regions during reverse transcription. Conclusion We conclude that an accurate and unambiguous tag mapping process is essential to increase the quality and the amount of information that can be extracted from SAGE experiments. This is supported by the results obtained here and also by the large impact that the erroneous interpretation of these data could have on downstream applications. PMID:17083742

  2. Building Energy Monitoring and Analysis

    SciTech Connect

    Hong, Tianzhen; Feng, Wei; Lu, Alison; Xia, Jianjun; Yang, Le; Shen, Qi; Im, Piljae; Bhandari, Mahabir

    2013-06-01

    U.S. and China are the world’s top two economics. Together they consumed one-third of the world’s primary energy. It is an unprecedented opportunity and challenge for governments, researchers and industries in both countries to join together to address energy issues and global climate change. Such joint collaboration has huge potential in creating new jobs in energy technologies and services. Buildings in the US and China consumed about 40% and 25% of the primary energy in both countries in 2010 respectively. Worldwide, the building sector is the largest contributor to the greenhouse gas emission. Better understanding and improving the energy performance of buildings is a critical step towards sustainable development and mitigation of global climate change. This project aimed to develop a standard methodology for building energy data definition, collection, presentation, and analysis; apply the developed methods to a standardized energy monitoring platform, including hardware and software, to collect and analyze building energy use data; and compile offline statistical data and online real-time data in both countries for fully understanding the current status of building energy use. This helps decode the driving forces behind the discrepancy of building energy use between the two countries; identify gaps and deficiencies of current building energy monitoring, data collection, and analysis; and create knowledge and tools to collect and analyze good building energy data to provide valuable and actionable information for key stakeholders.

  3. Continuous digital ECG analysis over accurate R-peak detection using adaptive wavelet technique.

    PubMed

    Gopalakrishnan Nair, T R; Geetha, A P; Asharani, M

    2013-10-01

    Worldwide, health care segment is under a severe challenge to achieve more accurate and intelligent biomedical systems in order to assist healthcare professionals with more accurate and consistent data as well as reliability. The role of ECG in healthcare is one of the paramount importances and it has got a multitude of abnormal relations and anomalies which characterizes intricate cardiovascular performance image. Until the recent past, ECG instruments and analysis played the role of providing the PQRST signal as raw observational output either on paper or on a console or in a file having many diagnostic clues embedded in the signal left to the expert cardiologist to look out for characteristic intervals and to detect the cardiovascular abnormality. Methods and practises are required more and more, to automate this process of cardiac expertise using knowledge engineering and an intelligent systems approach. This paper presents one of the challenging R-peak detections to classify diagnosis and estimate cardio disorders in a fully automated signal processing sequence. This study used an adaptive wavelet approach to generate an appropriate wavelet for R-signal identification under noise, baseband wandering and temporal variations of R-positions. This study designed an adaptive wavelet and successfully detected R- peak variations under various ECG signal conditions. The result and analysis of this method and the ways to use it for further purposes are presented here.

  4. Computer-Aided Energy Analysis for Buildings: An Assessment of Its Value for Students of Technology and Architecture.

    ERIC Educational Resources Information Center

    Ridenour, Steven

    1981-01-01

    Demonstrates that computer aided energy analysis improves students' (N=29) comprehension and prediction accuracy of energy consumption in buildings and confirms that a reasonably accurate building energy analysis computer program can be designed for student users. (Author/SK)

  5. Energy Deposition and Escape Fluxes Induced by Energetic Solar Wind Ions and ENAs Precipitating into Mars Atmosphere: Accurate Consideration of Energy Transfer Collisions

    NASA Astrophysics Data System (ADS)

    Kharchenko, V. A.; Lewkow, N.; Gacesa, M.

    2014-12-01

    Formation and evolution of neutral fluxes of atoms and molecules escaping from the Mars atmosphere have been investigated for the sputtering and photo-chemical mechanisms. Energy and momentum transfer in collisions between the atmospheric gas and fast atoms and molecules have been considered using our recently obtained angular and energy dependent cross sections[1]. We have showed that accurate angular dependent collision cross sections are critical for the description of the energy relaxation of precipitating keV energetic ions/ENAs and for computations of altitude profiles of the fast atom and molecule production rates in recoil collisions. Upward and escape fluxes of the secondary energetic He and O atoms and H2, N2, CO and CO2 molecules, induced by precipitating ENAs, have been determined and their non-thermal energy distribution functions have been computed at different altitudes for different solar conditions. Precipitation and energy deposition of the energetic H2O molecules and products of their dissociations into the Mars atmosphere in the Comet C/2013 A1 (Siding Spring) - Mars interaction have been modeled using accurate cross sections. Reflection of precipitating ENAs by the Mars atmosphere has been analyzed in detail. [1] N. Lewkow and V. Kharchenko, "Precipitation of Energetic Neutral Atoms and Escape Fluxes induced from the Mars Atmosphere, ApJ, v.790, p.98 (2014).

  6. Strategic Energy Analysis (Fact Sheet)

    SciTech Connect

    Not Available

    2014-02-01

    NREL complements its scientific research with high-quality, credible, technology-neutral, objective analysis that informs policy and investment decisions as renewable energy and energy efficiency technologies move from innovation through integration. This sheet highlights NREL's analytical capabilities and achievements.

  7. Fast and accurate sensitivity analysis of IMPT treatment plans using Polynomial Chaos Expansion

    NASA Astrophysics Data System (ADS)

    Perkó, Zoltán; van der Voort, Sebastian R.; van de Water, Steven; Hartman, Charlotte M. H.; Hoogeman, Mischa; Lathouwers, Danny

    2016-06-01

    The highly conformal planned dose distribution achievable in intensity modulated proton therapy (IMPT) can severely be compromised by uncertainties in patient setup and proton range. While several robust optimization approaches have been presented to address this issue, appropriate methods to accurately estimate the robustness of treatment plans are still lacking. To fill this gap we present Polynomial Chaos Expansion (PCE) techniques which are easily applicable and create a meta-model of the dose engine by approximating the dose in every voxel with multidimensional polynomials. This Polynomial Chaos (PC) model can be built in an automated fashion relatively cheaply and subsequently it can be used to perform comprehensive robustness analysis. We adapted PC to provide among others the expected dose, the dose variance, accurate probability distribution of dose-volume histogram (DVH) metrics (e.g. minimum tumor or maximum organ dose), exact bandwidths of DVHs, and to separate the effects of random and systematic errors. We present the outcome of our verification experiments based on 6 head-and-neck (HN) patients, and exemplify the usefulness of PCE by comparing a robust and a non-robust treatment plan for a selected HN case. The results suggest that PCE is highly valuable for both research and clinical applications.

  8. Fast and accurate sensitivity analysis of IMPT treatment plans using Polynomial Chaos Expansion.

    PubMed

    Perkó, Zoltán; van der Voort, Sebastian R; van de Water, Steven; Hartman, Charlotte M H; Hoogeman, Mischa; Lathouwers, Danny

    2016-06-21

    The highly conformal planned dose distribution achievable in intensity modulated proton therapy (IMPT) can severely be compromised by uncertainties in patient setup and proton range. While several robust optimization approaches have been presented to address this issue, appropriate methods to accurately estimate the robustness of treatment plans are still lacking. To fill this gap we present Polynomial Chaos Expansion (PCE) techniques which are easily applicable and create a meta-model of the dose engine by approximating the dose in every voxel with multidimensional polynomials. This Polynomial Chaos (PC) model can be built in an automated fashion relatively cheaply and subsequently it can be used to perform comprehensive robustness analysis. We adapted PC to provide among others the expected dose, the dose variance, accurate probability distribution of dose-volume histogram (DVH) metrics (e.g. minimum tumor or maximum organ dose), exact bandwidths of DVHs, and to separate the effects of random and systematic errors. We present the outcome of our verification experiments based on 6 head-and-neck (HN) patients, and exemplify the usefulness of PCE by comparing a robust and a non-robust treatment plan for a selected HN case. The results suggest that PCE is highly valuable for both research and clinical applications.

  9. Accurate palm vein recognition based on wavelet scattering and spectral regression kernel discriminant analysis

    NASA Astrophysics Data System (ADS)

    Elnasir, Selma; Shamsuddin, Siti Mariyam; Farokhi, Sajad

    2015-01-01

    Palm vein recognition (PVR) is a promising new biometric that has been applied successfully as a method of access control by many organizations, which has even further potential in the field of forensics. The palm vein pattern has highly discriminative features that are difficult to forge because of its subcutaneous position in the palm. Despite considerable progress and a few practical issues, providing accurate palm vein readings has remained an unsolved issue in biometrics. We propose a robust and more accurate PVR method based on the combination of wavelet scattering (WS) with spectral regression kernel discriminant analysis (SRKDA). As the dimension of WS generated features is quite large, SRKDA is required to reduce the extracted features to enhance the discrimination. The results based on two public databases-PolyU Hyper Spectral Palmprint public database and PolyU Multi Spectral Palmprint-show the high performance of the proposed scheme in comparison with state-of-the-art methods. The proposed approach scored a 99.44% identification rate and a 99.90% verification rate [equal error rate (EER)=0.1%] for the hyperspectral database and a 99.97% identification rate and a 99.98% verification rate (EER=0.019%) for the multispectral database.

  10. Accurate and flexible calibration technique for fringe projection profilometry by using encoded points and Fourier analysis

    NASA Astrophysics Data System (ADS)

    González, Andrés. L.; Contreras, Carlos R.; Meneses, Jaime E.

    2014-05-01

    In order to get measures with a high accurate, three-dimensional reconstruction systems are implemented in industrial, medical, and investigative fields. To obtain high accurate is necessary to carry out an appropriate calibration procedure. In fringe projection profilometry, this procedure allows obtaining a relation between absolute phase and three-dimensional (3D) information of the object in study; however, to execute such procedure a precise movement stage is required. A fringe projection system is formed by a projector, a digital camera and a control unit, called like a projection-acquisition unit in this paper. The calibration of the projection-acquisition unit consists in to establish the parameters that are required to transform the phase of the projected fringes to metric coordinates of the object surface. These parameters are a function of the intrinsic and extrinsic parameters of both camera and projector, due to the projector is modeled as an inverse camera. For this purpose, in this paper a novel and flexible calibration method that allows calibrating any device that works with fringe projection profilometry is proposed. In this method is used a reference plane placed in random positions and the projection of an encoded pattern of control points. The camera parameters are computed using Zhang's calibration method; and the projector parameters are computed from the camera parameters and the phase of the pattern of control points, which is determined by using Fourier analysis. Experimental results are presented to demonstrate the performance of the calibration method.

  11. Accurate double many-body expansion potential energy surface for the 2(1)A' state of N2O.

    PubMed

    Li, Jing; Varandas, António J C

    2014-08-28

    An accurate double many-body expansion potential energy surface is reported for the 2(1)A' state of N2O. The new double many-body expansion (DMBE) form has been fitted to a wealth of ab initio points that have been calculated at the multi-reference configuration interaction level using the full-valence-complete-active-space wave function as reference and the cc-pVQZ basis set, and subsequently corrected semiempirically via double many-body expansion-scaled external correlation method to extrapolate the calculated energies to the limit of a complete basis set and, most importantly, the limit of an infinite configuration interaction expansion. The topographical features of the novel potential energy surface are then examined in detail and compared with corresponding attributes of other potential functions available in the literature. Exploratory trajectories have also been run on this DMBE form with the quasiclassical trajectory method, with the thermal rate constant so determined at room temperature significantly enhancing agreement with experimental data.

  12. Accurate all-electron correlation energies for the closed-shell atoms from Ar to Rn and their relationship to the corresponding MP2 correlation energies.

    PubMed

    McCarthy, Shane P; Thakkar, Ajit J

    2011-01-28

    All-electron correlation energies E(c) are not very well-known for atoms with more than 18 electrons. Hence, coupled-cluster calculations in carefully designed basis sets are combined with fully converged second-order Møller-Plesset perturbation theory (MP2) computations to obtain fairly accurate, nonrelativistic E(c) values for the 12 closed-shell atoms from Ar to Rn. These energies will be useful for the evaluation and parameterization of density functionals. The results show that MP2 overestimates ∣E(c)∣ for heavy atoms. Spin-component scaling of the MP2 correlation energy is used to provide a simple explanation for this overestimation.

  13. Time-Accurate Simulations and Acoustic Analysis of Slat Free-Shear Layer

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Singer, Bart A.; Berkman, Mert E.

    2001-01-01

    A detailed computational aeroacoustic analysis of a high-lift flow field is performed. Time-accurate Reynolds Averaged Navier-Stokes (RANS) computations simulate the free shear layer that originates from the slat cusp. Both unforced and forced cases are studied. Preliminary results show that the shear layer is a good amplifier of disturbances in the low to mid-frequency range. The Ffowcs-Williams and Hawkings equation is solved to determine the acoustic field using the unsteady flow data from the RANS calculations. The noise radiated from the excited shear layer has a spectral shape qualitatively similar to that obtained from measurements in a corresponding experimental study of the high-lift system.

  14. Global analysis of the Deinococcus radiodurans proteome by using accurate mass tags

    PubMed Central

    Lipton, Mary S.; Paša-Tolić, Ljiljana; Anderson, Gordon A.; Anderson, David J.; Auberry, Deanna L.; Battista, John R.; Daly, Michael J.; Fredrickson, Jim; Hixson, Kim K.; Kostandarithes, Heather; Masselon, Christophe; Markillie, Lye Meng; Moore, Ronald J.; Romine, Margaret F.; Shen, Yufeng; Stritmatter, Eric; Tolić, Nikola; Udseth, Harold R.; Venkateswaran, Amudhan; Wong, Kwong-Kwok; Zhao, Rui; Smith, Richard D.

    2002-01-01

    Understanding biological systems and the roles of their constituents is facilitated by the ability to make quantitative, sensitive, and comprehensive measurements of how their proteome changes, e.g., in response to environmental perturbations. To this end, we have developed a high-throughput methodology to characterize an organism's dynamic proteome based on the combination of global enzymatic digestion, high-resolution liquid chromatographic separations, and analysis by Fourier transform ion cyclotron resonance mass spectrometry. The peptides produced serve as accurate mass tags for the proteins and have been used to identify with high confidence >61% of the predicted proteome for the ionizing radiation-resistant bacterium Deinococcus radiodurans. This fraction represents the broadest proteome coverage for any organism to date and includes 715 proteins previously annotated as either hypothetical or conserved hypothetical. PMID:12177431

  15. Geometric constraints in semiclassical initial value representation calculations in Cartesian coordinates: accurate reduction in zero-point energy.

    PubMed

    Issack, Bilkiss B; Roy, Pierre-Nicholas

    2005-08-22

    An approach for the inclusion of geometric constraints in semiclassical initial value representation calculations is introduced. An important aspect of the approach is that Cartesian coordinates are used throughout. We devised an algorithm for the constrained sampling of initial conditions through the use of multivariate Gaussian distribution based on a projected Hessian. We also propose an approach for the constrained evaluation of the so-called Herman-Kluk prefactor in its exact log-derivative form. Sample calculations are performed for free and constrained rare-gas trimers. The results show that the proposed approach provides an accurate evaluation of the reduction in zero-point energy. Exact basis set calculations are used to assess the accuracy of the semiclassical results. Since Cartesian coordinates are used, the approach is general and applicable to a variety of molecular and atomic systems.

  16. An algorithm for selecting the most accurate protocol for contact angle measurement by drop shape analysis.

    PubMed

    Xu, Z N

    2014-12-01

    In this study, an error analysis is performed to study real water drop images and the corresponding numerically generated water drop profiles for three widely used static contact angle algorithms: the circle- and ellipse-fitting algorithms and the axisymmetric drop shape analysis-profile (ADSA-P) algorithm. The results demonstrate the accuracy of the numerically generated drop profiles based on the Laplace equation. A significant number of water drop profiles with different volumes, contact angles, and noise levels are generated, and the influences of the three factors on the accuracies of the three algorithms are systematically investigated. The results reveal that the above-mentioned three algorithms are complementary. In fact, the circle- and ellipse-fitting algorithms show low errors and are highly resistant to noise for water drops with small/medium volumes and contact angles, while for water drop with large volumes and contact angles just the ADSA-P algorithm can meet accuracy requirement. However, this algorithm introduces significant errors in the case of small volumes and contact angles because of its high sensitivity to noise. The critical water drop volumes of the circle- and ellipse-fitting algorithms corresponding to a certain contact angle error are obtained through a significant amount of computation. To improve the precision of the static contact angle measurement, a more accurate algorithm based on a combination of the three algorithms is proposed. Following a systematic investigation, the algorithm selection rule is described in detail, while maintaining the advantages of the three algorithms and overcoming their deficiencies. In general, static contact angles over the entire hydrophobicity range can be accurately evaluated using the proposed algorithm. The ease of erroneous judgment in static contact angle measurements is avoided. The proposed algorithm is validated by a static contact angle evaluation of real and numerically generated water drop

  17. An algorithm for selecting the most accurate protocol for contact angle measurement by drop shape analysis

    NASA Astrophysics Data System (ADS)

    Xu, Z. N.

    2014-12-01

    In this study, an error analysis is performed to study real water drop images and the corresponding numerically generated water drop profiles for three widely used static contact angle algorithms: the circle- and ellipse-fitting algorithms and the axisymmetric drop shape analysis-profile (ADSA-P) algorithm. The results demonstrate the accuracy of the numerically generated drop profiles based on the Laplace equation. A significant number of water drop profiles with different volumes, contact angles, and noise levels are generated, and the influences of the three factors on the accuracies of the three algorithms are systematically investigated. The results reveal that the above-mentioned three algorithms are complementary. In fact, the circle- and ellipse-fitting algorithms show low errors and are highly resistant to noise for water drops with small/medium volumes and contact angles, while for water drop with large volumes and contact angles just the ADSA-P algorithm can meet accuracy requirement. However, this algorithm introduces significant errors in the case of small volumes and contact angles because of its high sensitivity to noise. The critical water drop volumes of the circle- and ellipse-fitting algorithms corresponding to a certain contact angle error are obtained through a significant amount of computation. To improve the precision of the static contact angle measurement, a more accurate algorithm based on a combination of the three algorithms is proposed. Following a systematic investigation, the algorithm selection rule is described in detail, while maintaining the advantages of the three algorithms and overcoming their deficiencies. In general, static contact angles over the entire hydrophobicity range can be accurately evaluated using the proposed algorithm. The ease of erroneous judgment in static contact angle measurements is avoided. The proposed algorithm is validated by a static contact angle evaluation of real and numerically generated water drop

  18. Experimental and theoretical oscillator strengths of Mg i for accurate abundance analysis

    NASA Astrophysics Data System (ADS)

    Pehlivan Rhodin, A.; Hartman, H.; Nilsson, H.; Jönsson, P.

    2017-02-01

    Context. With the aid of stellar abundance analysis, it is possible to study the galactic formation and evolution. Magnesium is an important element to trace the α-element evolution in our Galaxy. For chemical abundance analysis, such as magnesium abundance, accurate and complete atomic data are essential. Inaccurate atomic data lead to uncertain abundances and prevent discrimination between different evolution models. Aims: We study the spectrum of neutral magnesium from laboratory measurements and theoretical calculations. Our aim is to improve the oscillator strengths (f-values) of Mg i lines and to create a complete set of accurate atomic data, particularly for the near-IR region. Methods: We derived oscillator strengths by combining the experimental branching fractions with radiative lifetimes reported in the literature and computed in this work. A hollow cathode discharge lamp was used to produce free atoms in the plasma and a Fourier transform spectrometer recorded the intensity-calibrated high-resolution spectra. In addition, we performed theoretical calculations using the multiconfiguration Hartree-Fock program ATSP2K. Results: This project provides a set of experimental and theoretical oscillator strengths. We derived 34 experimental oscillator strengths. Except from the Mg i optical triplet lines (3p 3P°0,1,2-4s 3S1), these oscillator strengths are measured for the first time. The theoretical oscillator strengths are in very good agreement with the experimental data and complement the missing transitions of the experimental data up to n = 7 from even and odd parity terms. We present an evaluated set of oscillator strengths, gf, with uncertainties as small as 5%. The new values of the Mg i optical triplet line (3p 3P°0,1,2-4s 3S1) oscillator strength values are 0.08 dex larger than the previous measurements.

  19. FAMBE-pH: a fast and accurate method to compute the total solvation free energies of proteins.

    PubMed

    Vorobjev, Yury N; Vila, Jorge A; Scheraga, Harold A

    2008-09-04

    A fast and accurate method to compute the total solvation free energies of proteins as a function of pH is presented. The method makes use of a combination of approaches, some of which have already appeared in the literature; (i) the Poisson equation is solved with an optimized fast adaptive multigrid boundary element (FAMBE) method; (ii) the electrostatic free energies of the ionizable sites are calculated for their neutral and charged states by using a detailed model of atomic charges; (iii) a set of optimal atomic radii is used to define a precise dielectric surface interface; (iv) a multilevel adaptive tessellation of this dielectric surface interface is achieved by using multisized boundary elements; and (v) 1:1 salt effects are included. The equilibrium proton binding/release is calculated with the Tanford-Schellman integral if the proteins contain more than approximately 20-25 ionizable groups; for a smaller number of ionizable groups, the ionization partition function is calculated directly. The FAMBE method is tested as a function of pH (FAMBE-pH) with three proteins, namely, bovine pancreatic trypsin inhibitor (BPTI), hen egg white lysozyme (HEWL), and bovine pancreatic ribonuclease A (RNaseA). The results are (a) the FAMBE-pH method reproduces the observed pK a's of the ionizable groups of these proteins within an average absolute value of 0.4 p K units and a maximum error of 1.2 p K units and (b) comparison of the calculated total pH-dependent solvation free energy for BPTI, between the exact calculation of the ionization partition function and the Tanford-Schellman integral method, shows agreement within 1.2 kcal/mol. These results indicate that calculation of total solvation free energies with the FAMBE-pH method can provide an accurate prediction of protein conformational stability at a given fixed pH and, if coupled with molecular mechanics or molecular dynamics methods, can also be used for more realistic studies of protein folding, unfolding, and

  20. Toward Sensitive and Accurate Analysis of Antibody Biotherapeutics by Liquid Chromatography Coupled with Mass Spectrometry

    PubMed Central

    An, Bo; Zhang, Ming

    2014-01-01

    Remarkable methodological advances in the past decade have expanded the application of liquid chromatography coupled with mass spectrometry (LC/MS) analysis of biotherapeutics. Currently, LC/MS represents a promising alternative or supplement to the traditional ligand binding assay (LBA) in the pharmacokinetic, pharmacodynamic, and toxicokinetic studies of protein drugs, owing to the rapid and cost-effective method development, high specificity and reproducibility, low sample consumption, the capacity of analyzing multiple targets in one analysis, and the fact that a validated method can be readily adapted across various matrices and species. While promising, technical challenges associated with sensitivity, sample preparation, method development, and quantitative accuracy need to be addressed to enable full utilization of LC/MS. This article introduces the rationale and technical challenges of LC/MS techniques in biotherapeutics analysis and summarizes recently developed strategies to alleviate these challenges. Applications of LC/MS techniques on quantification and characterization of antibody biotherapeutics are also discussed. We speculate that despite the highly attractive features of LC/MS, it will not fully replace traditional assays such as LBA in the foreseeable future; instead, the forthcoming trend is likely the conjunction of biochemical techniques with versatile LC/MS approaches to achieve accurate, sensitive, and unbiased characterization of biotherapeutics in highly complex pharmaceutical/biologic matrices. Such combinations will constitute powerful tools to tackle the challenges posed by the rapidly growing needs for biotherapeutics development. PMID:25185260

  1. Energy consumption analysis for the Mars deep space station

    NASA Technical Reports Server (NTRS)

    Hayes, N. V.

    1982-01-01

    Results for the energy consumption analysis at the Mars deep space station are presented. It is shown that the major energy consumers are the 64-Meter antenna building and the operations support building. Verification of the antenna's energy consumption is highly dependent on an accurate knowlege of the tracking operations. The importance of a regular maintenance schedule for the watt hour meters installed at the station is indicated.

  2. Accurate and efficient calculation of excitation energies with the active-space particle-particle random phase approximation

    DOE PAGES

    Zhang, Du; Yang, Weitao

    2016-10-13

    An efficient method for calculating excitation energies based on the particle-particle random phase approximation (ppRPA) is presented. Neglecting the contributions from the high-lying virtual states and the low-lying core states leads to the significantly smaller active-space ppRPA matrix while keeping the error to within 0.05 eV from the corresponding full ppRPA excitation energies. The resulting computational cost is significantly reduced and becomes less than the construction of the non-local Fock exchange potential matrix in the self-consistent-field (SCF) procedure. With only a modest number of active orbitals, the original ppRPA singlet-triplet (ST) gaps as well as the low-lying single and doublemore » excitation energies can be accurately reproduced at much reduced computational costs, up to 100 times faster than the iterative Davidson diagonalization of the original full ppRPA matrix. For high-lying Rydberg excitations where the Davidson algorithm fails, the computational savings of active-space ppRPA with respect to the direct diagonalization is even more dramatic. The virtues of the underlying full ppRPA combined with the significantly lower computational cost of the active-space approach will significantly expand the applicability of the ppRPA method to calculate excitation energies at a cost of O(K^{4}), with a prefactor much smaller than a single SCF Hartree-Fock (HF)/hybrid functional calculation, thus opening up new possibilities for the quantum mechanical study of excited state electronic structure of large systems.« less

  3. Accurate and efficient calculation of excitation energies with the active-space particle-particle random phase approximation

    SciTech Connect

    Zhang, Du; Yang, Weitao

    2016-10-13

    An efficient method for calculating excitation energies based on the particle-particle random phase approximation (ppRPA) is presented. Neglecting the contributions from the high-lying virtual states and the low-lying core states leads to the significantly smaller active-space ppRPA matrix while keeping the error to within 0.05 eV from the corresponding full ppRPA excitation energies. The resulting computational cost is significantly reduced and becomes less than the construction of the non-local Fock exchange potential matrix in the self-consistent-field (SCF) procedure. With only a modest number of active orbitals, the original ppRPA singlet-triplet (ST) gaps as well as the low-lying single and double excitation energies can be accurately reproduced at much reduced computational costs, up to 100 times faster than the iterative Davidson diagonalization of the original full ppRPA matrix. For high-lying Rydberg excitations where the Davidson algorithm fails, the computational savings of active-space ppRPA with respect to the direct diagonalization is even more dramatic. The virtues of the underlying full ppRPA combined with the significantly lower computational cost of the active-space approach will significantly expand the applicability of the ppRPA method to calculate excitation energies at a cost of O(K^{4}), with a prefactor much smaller than a single SCF Hartree-Fock (HF)/hybrid functional calculation, thus opening up new possibilities for the quantum mechanical study of excited state electronic structure of large systems.

  4. Accurate and efficient calculation of excitation energies with the active-space particle-particle random phase approximation

    NASA Astrophysics Data System (ADS)

    Zhang, Du; Yang, Weitao

    2016-10-01

    An efficient method for calculating excitation energies based on the particle-particle random phase approximation (ppRPA) is presented. Neglecting the contributions from the high-lying virtual states and the low-lying core states leads to the significantly smaller active-space ppRPA matrix while keeping the error to within 0.05 eV from the corresponding full ppRPA excitation energies. The resulting computational cost is significantly reduced and becomes less than the construction of the non-local Fock exchange potential matrix in the self-consistent-field (SCF) procedure. With only a modest number of active orbitals, the original ppRPA singlet-triplet (ST) gaps as well as the low-lying single and double excitation energies can be accurately reproduced at much reduced computational costs, up to 100 times faster than the iterative Davidson diagonalization of the original full ppRPA matrix. For high-lying Rydberg excitations where the Davidson algorithm fails, the computational savings of active-space ppRPA with respect to the direct diagonalization is even more dramatic. The virtues of the underlying full ppRPA combined with the significantly lower computational cost of the active-space approach will significantly expand the applicability of the ppRPA method to calculate excitation energies at a cost of O(K4), with a prefactor much smaller than a single SCF Hartree-Fock (HF)/hybrid functional calculation, thus opening up new possibilities for the quantum mechanical study of excited state electronic structure of large systems.

  5. Accurate energy bands calculated by the hybrid quasiparticle self-consistent GW method implemented in the ecalj package

    NASA Astrophysics Data System (ADS)

    Deguchi, Daiki; Sato, Kazunori; Kino, Hiori; Kotani, Takao

    2016-05-01

    We have recently implemented a new version of the quasiparticle self-consistent GW (QSGW) method in the ecalj package released at http://github.com/tkotani/ecalj. Since the new version of the ecalj package is numerically stable and more accurate than the previous versions, we can perform calculations easily without being bothered with tuning input parameters. Here we examine its ability to describe energy band properties, e.g., band-gap energy, eigenvalues at special points, and effective mass, for a variety of semiconductors and insulators. We treat C, Si, Ge, Sn, SiC (in 2H, 3C, and 4H structures), (Al, Ga, In) × (N, P, As, Sb), (Zn, Cd, Mg) × (O, S, Se, Te), SiO2, HfO2, ZrO2, SrTiO3, PbS, PbTe, MnO, NiO, and HgO. We propose that a hybrid QSGW method, where we mix 80% of QSGW and 20% of LDA, gives universally good agreement with experiments for these materials.

  6. Institutional analysis for energy policy

    SciTech Connect

    Morris, F.A.; Cole, R.J.

    1980-07-01

    This report summarizes principles, techniques, and other information for doing institutional analyses in the area of energy policy. The report was prepared to support DOE's Regional Issues Identification and Assessment (RIIA) program. RIIA identifies environmental, health, safety, socioeconomic, and institutional issues that could accompany hypothetical future scenarios for energy consumption and production on a regional basis. Chapter 1 provides some theoretical grounding in institutional analysis. Chapter 2 provides information on constructing institutional maps of the processes for bringing on line energy technologies and facilities contemplated in RIIA scenarios. Chapter 3 assesses the institutional constraints, opportunities, and impacts that affect whether these technologies and facilities would in fact be developed. Chapters 4 and 5 show how institutional analysis can support use of exercises such as RIIA in planning institutional change and making energy policy choices.

  7. Accurate determination of succinimide degradation products using high fidelity trypsin digestion peptide map analysis.

    PubMed

    Yu, X Christopher; Joe, Koman; Zhang, Yu; Adriano, Andrea; Wang, Yaning; Gazzano-Santoro, Helene; Keck, Rodney G; Deperalta, Galahad; Ling, Victor

    2011-08-01

    We report an efficient, high fidelity trypsin digestion method for peptide map analysis. This method minimizes artifacts caused by the sample preparation process, and we show its utility for the accurate determination of succinimide formation in a degraded monoclonal antibody product. A basic charge variant was detected by imaged capillary isoelectric focusing and was shown with reduced antigen binding and biological activity. Samples were reduced under denaturing conditions at pH 5.0, and digestion of the reduced protein with porcine trypsin was performed at pH 7.0 for 1 h. Following reversed phase high-performance liquid chromatography and online mass spectrometric analysis, succinimide formation was identified at Asp30 in the light chain. This result contrasts with the observation of only iso-Asp and Asp residues under conventional sample preparation conditions, which are therefore concluded to be artificially generated. The Asp30 residue is seen in the cocrystal structure model to participate in favorable charge interaction with an antigen molecule. Formation of succinimide and the resulting loss of negative charge are therefore hypothesized to be the degradation mechanism. After treatment of the degraded antibody sample to mildly alkaline pH conditions, we observed only Asp residue as the succinimide hydrolysis product and concurrent recovery of biological activity.

  8. Enantiomeric separation in comprehensive two-dimensional gas chromatography with accurate mass analysis.

    PubMed

    Chin, Sung-Tong; Nolvachai, Yada; Marriott, Philip J

    2014-11-01

    Chiral comprehensive two-dimensional gas chromatography (eGC×GC) coupled to quadrupole-accurate mass time-of-flight mass spectrometry (QTOFMS) was evaluated for its capability to report the chiral composition of several monoterpenes, namely, α-pinene, β-pinene, and limonene in cardamom oil. Enantiomers in a standard mixture were fully resolved by direct enantiomeric-GC analysis with a 2,3-di-O-methyl-6-t-butylsilyl derivatized β-cyclodextrin phase; however, the (+)-(R)-limonene enantiomer in cardamom oil was overlapped with other background components including cymene and cineole. Verification of (+)-(R)-limonene components based on characteristic ions at m/z 136, 121, and 107 acquired by chiral single-dimension GC-QTOFMS in the alternate MS/MSMS mode of operation was unsuccessful due to similar parent/daughter ions generated by interfering or co-eluting cymene and cineole. Column phases SUPELCOWAX, SLB-IL111, HP-88, and SLB-IL59, were incorporated as the second dimension column ((2)D) in chiral GC×GC analysis; the SLB-IL59 offered the best resolution for the tested monoterpene enantiomers from the matrix background. Enantiomeric ratios for α-pinene, β-pinene, and limonene were determined to be 1.325, 2.703, and 1.040, respectively, in the cardamom oil sample based on relative peak area data.

  9. Accurate airway segmentation based on intensity structure analysis and graph-cut

    NASA Astrophysics Data System (ADS)

    Meng, Qier; Kitsaka, Takayuki; Nimura, Yukitaka; Oda, Masahiro; Mori, Kensaku

    2016-03-01

    This paper presents a novel airway segmentation method based on intensity structure analysis and graph-cut. Airway segmentation is an important step in analyzing chest CT volumes for computerized lung cancer detection, emphysema diagnosis, asthma diagnosis, and pre- and intra-operative bronchoscope navigation. However, obtaining a complete 3-D airway tree structure from a CT volume is quite challenging. Several researchers have proposed automated algorithms basically based on region growing and machine learning techniques. However these methods failed to detect the peripheral bronchi branches. They caused a large amount of leakage. This paper presents a novel approach that permits more accurate extraction of complex bronchial airway region. Our method are composed of three steps. First, the Hessian analysis is utilized for enhancing the line-like structure in CT volumes, then a multiscale cavity-enhancement filter is employed to detect the cavity-like structure from the previous enhanced result. In the second step, we utilize the support vector machine (SVM) to construct a classifier for removing the FP regions generated. Finally, the graph-cut algorithm is utilized to connect all of the candidate voxels to form an integrated airway tree. We applied this method to sixteen cases of 3D chest CT volumes. The results showed that the branch detection rate of this method can reach about 77.7% without leaking into the lung parenchyma areas.

  10. Transport Energy Impact Analysis; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Gonder, J.

    2015-05-13

    Presented at the Sustainable Transportation Energy Pathways Spring 2015 Symposium on May 13, 2015, this presentation by Jeff Gonder of the National Renewable Energy Laboratory (NREL) provides information about NREL's transportation energy impact analysis of connected and automated vehicles.

  11. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the Br(2P, 2P3/2) + CH4 → HBr + CH3 reaction

    NASA Astrophysics Data System (ADS)

    Czakó, Gábor

    2013-04-01

    Chemically accurate full-dimensional non-spin-orbit and spin-orbit (SO) ground-state potential energy surfaces (PESs) are obtained for the Br + CH4 → HBr + CH3 reaction by fitting 21 574 composite ab initio energy points. The composite method considers electron correlation methods up to CCSD(T), basis sets up to aug-cc-pwCVTZ-PP, correlation of the core electrons, scalar relativistic effects via an effective core potential (ECP), and SO corrections, thereby achieving an accuracy better than 0.5 kcal/mol. Benchmark structures and relative energies are computed for the stationary points using the ab initio focal-point analysis (FPA) scheme based on both ECP and Douglas-Kroll approaches providing all-electron relativistic CCSDT(Q)/complete-basis-set quality energies. The PESs accurately describe the saddle point of the abstraction reaction and the van der Waals complexes in the entrance and product channels. The SO-corrected PES provides a classical barrier height of 7285(7232 ± 50) cm-1, De values of 867(799 ± 10) and 399(344 ± 10) cm-1 for the complexes CH3-HBr and CH3-BrH, respectively, and reaction endothermicity of 7867(7857 ± 50) cm-1, in excellent agreement with the new, FPA-based benchmark data shown in parentheses. The difference between the Br + CH4 asymptotes of the non-SO and SO PESs is 1240 cm-1, in good agreement with the experiment (1228 cm-1). Quasiclassical trajectory calculations based on more than 13 million trajectories for the late-barrier Br + CH4(vk = 0, 1) [k = 1, 2, 3, 4] reactions show that the vibrational energy, especially the excitation of the stretching modes, activates the reaction much more efficiently than translational energy, in agreement with the extended Polanyi rules. Angular distributions show dominant backward scattering for the ground-state reaction and forward scattering for the stretching-excited reactions. The reactivity on the non-SO PES is about 3-5 times larger than that on the SO PES in a wide collision energy

  12. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the Br(2P, 2P(3∕2)) + CH4 → HBr + CH3 reaction.

    PubMed

    Czakó, Gábor

    2013-04-07

    Chemically accurate full-dimensional non-spin-orbit and spin-orbit (SO) ground-state potential energy surfaces (PESs) are obtained for the Br + CH4 → HBr + CH3 reaction by fitting 21 574 composite ab initio energy points. The composite method considers electron correlation methods up to CCSD(T), basis sets up to aug-cc-pwCVTZ-PP, correlation of the core electrons, scalar relativistic effects via an effective core potential (ECP), and SO corrections, thereby achieving an accuracy better than 0.5 kcal∕mol. Benchmark structures and relative energies are computed for the stationary points using the ab initio focal-point analysis (FPA) scheme based on both ECP and Douglas-Kroll approaches providing all-electron relativistic CCSDT(Q)∕complete-basis-set quality energies. The PESs accurately describe the saddle point of the abstraction reaction and the van der Waals complexes in the entrance and product channels. The SO-corrected PES provides a classical barrier height of 7285(7232 ± 50) cm(-1), De values of 867(799 ± 10) and 399(344 ± 10) cm(-1) for the complexes CH3-HBr and CH3-BrH, respectively, and reaction endothermicity of 7867(7857 ± 50) cm(-1), in excellent agreement with the new, FPA-based benchmark data shown in parentheses. The difference between the Br + CH4 asymptotes of the non-SO and SO PESs is 1240 cm(-1), in good agreement with the experiment (1228 cm(-1)). Quasiclassical trajectory calculations based on more than 13 million trajectories for the late-barrier Br + CH4(vk = 0, 1) [k = 1, 2, 3, 4] reactions show that the vibrational energy, especially the excitation of the stretching modes, activates the reaction much more efficiently than translational energy, in agreement with the extended Polanyi rules. Angular distributions show dominant backward scattering for the ground-state reaction and forward scattering for the stretching-excited reactions. The reactivity on the non-SO PES is about 3-5 times larger than that on the SO PES in a wide

  13. Energy savings analysis for energy monitoring and control systems

    NASA Astrophysics Data System (ADS)

    Flagg, Ken; Pierpoint, William

    1995-01-01

    The energy savings analysis report and software was developed to calculate savings when implementing typical energy conservation strategies. The analysis is based on ASHRAE Bin methods. Strategies include: scheduled start/stop, optimized start/stop, and temperature reset.

  14. Fully Automatic System for Accurate Localisation and Analysis of Cephalometric Landmarks in Lateral Cephalograms

    PubMed Central

    Lindner, Claudia; Wang, Ching-Wei; Huang, Cheng-Ta; Li, Chung-Hsing; Chang, Sheng-Wei; Cootes, Tim F.

    2016-01-01

    Cephalometric tracing is a standard analysis tool for orthodontic diagnosis and treatment planning. The aim of this study was to develop and validate a fully automatic landmark annotation (FALA) system for finding cephalometric landmarks in lateral cephalograms and its application to the classification of skeletal malformations. Digital cephalograms of 400 subjects (age range: 7–76 years) were available. All cephalograms had been manually traced by two experienced orthodontists with 19 cephalometric landmarks, and eight clinical parameters had been calculated for each subject. A FALA system to locate the 19 landmarks in lateral cephalograms was developed. The system was evaluated via comparison to the manual tracings, and the automatically located landmarks were used for classification of the clinical parameters. The system achieved an average point-to-point error of 1.2 mm, and 84.7% of landmarks were located within the clinically accepted precision range of 2.0 mm. The automatic landmark localisation performance was within the inter-observer variability between two clinical experts. The automatic classification achieved an average classification accuracy of 83.4% which was comparable to an experienced orthodontist. The FALA system rapidly and accurately locates and analyses cephalometric landmarks in lateral cephalograms, and has the potential to significantly improve the clinical work flow in orthodontic treatment. PMID:27645567

  15. Interaction of metal ions with biomolecular ligands: how accurate are calculated free energies associated with metal ion complexation?

    PubMed

    Gutten, Ondrej; Beššeová, Ivana; Rulíšek, Lubomír

    2011-10-20

    To address fundamental questions in bioinorganic chemistry, such as metal ion selectivity, accurate computational protocols for both the gas-phase association of metal-ligand complexes and solvation/desolvation energies of the species involved are needed. In this work, we attempt to critically evaluate the performance of the ab initio and DFT electronic structure methods available and recent solvation models in calculations of the energetics associated with metal ion complexation. On the example of five model complexes ([M(II)(CH(3)S)(H(2)O)](+), [M(II)(H(2)O)(2)(H(2)S)(NH(3))](2+), [M(II)(CH(3)S)(NH(3))(H(2)O)(CH(3)COO)], [M(II)(H(2)O)(3)(SH)(CH(3)COO)(Im)], [M(II)(H(2)S)(H(2)O)(CH(3)COO)(PhOH)(Im)](+) in typical coordination geometries) and four metal ions (Fe(2+), Cu(2+), Zn(2+), and Cd(2+); representing open- and closed-shell and the first- and second-row transition metal elements), we provide reference values for the gas-phase complexation energies, as presumably obtained using the CCSD(T)/aug-cc-pVTZ method, and compare them with cheaper methods, such as DFT and RI-MP2, that can be used for large-scale calculations. We also discuss two possible definitions of interaction energies underlying the theoretically predicted metal-ion selectivity and the effect of geometry optimization on these values. Finally, popular solvation models, such as COSMO-RS and SMD, are used to demonstrate whether quantum chemical calculations can provide the overall free enthalpy (ΔG) changes in the range of the expected experimental values for the model complexes or match the experimental stability constants in the case of three complexes for which the experimental data exist. The data presented highlight several intricacies in the theoretical predictions of the experimental stability constants: the covalent character of some metal-ligand bonds (e.g., Cu(II)-thiolate) causing larger errors in the gas-phase complexation energies, inaccuracies in the treatment of solvation of the

  16. Methods for Applying Accurate Digital PCR Analysis on Low Copy DNA Samples

    PubMed Central

    Whale, Alexandra S.; Cowen, Simon; Foy, Carole A.; Huggett, Jim F.

    2013-01-01

    Digital PCR (dPCR) is a highly accurate molecular approach, capable of precise measurements, offering a number of unique opportunities. However, in its current format dPCR can be limited by the amount of sample that can be analysed and consequently additional considerations such as performing multiplex reactions or pre-amplification can be considered. This study investigated the impact of duplexing and pre-amplification on dPCR analysis by using three different assays targeting a model template (a portion of the Arabidopsis thaliana alcohol dehydrogenase gene). We also investigated the impact of different template types (linearised plasmid clone and more complex genomic DNA) on measurement precision using dPCR. We were able to demonstrate that duplex dPCR can provide a more precise measurement than uniplex dPCR, while applying pre-amplification or varying template type can significantly decrease the precision of dPCR. Furthermore, we also demonstrate that the pre-amplification step can introduce measurement bias that is not consistent between experiments for a sample or assay and so could not be compensated for during the analysis of this data set. We also describe a model for estimating the prevalence of molecular dropout and identify this as a source of dPCR imprecision. Our data have demonstrated that the precision afforded by dPCR at low sample concentration can exceed that of the same template post pre-amplification thereby negating the need for this additional step. Our findings also highlight the technical differences between different templates types containing the same sequence that must be considered if plasmid DNA is to be used to assess or control for more complex templates like genomic DNA. PMID:23472156

  17. Accurate means of detecting and characterizing abnormal patterns of ventricular activation by phase image analysis

    SciTech Connect

    Botvinick, E.H.; Frais, M.A.; Shosa, D.W.; O'Connell, J.W.; Pacheco-Alvarez, J.A.; Scheinman, M.; Hattner, R.S.; Morady, F.; Faulkner, D.B.

    1982-08-01

    The ability of scintigraphic phase image analysis to characterize patterns of abnormal ventricular activation was investigated. The pattern of phase distribution and sequential phase changes over both right and left ventricular regions of interest were evaluated in 16 patients with normal electrical activation and wall motion and compared with those in 8 patients with an artificial pacemaker and 4 patients with sinus rhythm with the Wolff-Parkinson-White syndrome and delta waves. Normally, the site of earliest phase angle was seen at the base of the interventricular septum, with sequential change affecting the body of the septum and the cardiac apex and then spreading laterally to involve the body of both ventricles. The site of earliest phase angle was located at the apex of the right ventricle in seven patients with a right ventricular endocardial pacemaker and on the lateral left ventricular wall in one patient with a left ventricular epicardial pacemaker. In each case the site corresponded exactly to the position of the pacing electrode as seen on posteroanterior and left lateral chest X-ray films, and sequential phase changes spread from the initial focus to affect both ventricles. In each of the patients with the Wolff-Parkinson-White syndrome, the site of earliest ventricular phase angle was located, and it corresponded exactly to the site of the bypass tract as determined by endocardial mapping. In this way, four bypass pathways, two posterior left paraseptal, one left lateral and one right lateral, were correctly localized scintigraphically. On the basis of the sequence of mechanical contraction, phase image analysis provides an accurate noninvasive method of detecting abnormal foci of ventricular activation.

  18. Fast and Accurate Radiative Transfer Calculations Using Principal Component Analysis for (Exo-)Planetary Retrieval Models

    NASA Astrophysics Data System (ADS)

    Kopparla, P.; Natraj, V.; Shia, R. L.; Spurr, R. J. D.; Crisp, D.; Yung, Y. L.

    2015-12-01

    Radiative transfer (RT) computations form the engine of atmospheric retrieval codes. However, full treatment of RT processes is computationally expensive, prompting usage of two-stream approximations in current exoplanetary atmospheric retrieval codes [Line et al., 2013]. Natraj et al. [2005, 2010] and Spurr and Natraj [2013] demonstrated the ability of a technique using principal component analysis (PCA) to speed up RT computations. In the PCA method for RT performance enhancement, empirical orthogonal functions are developed for binned sets of inherent optical properties that possess some redundancy; costly multiple-scattering RT calculations are only done for those few optical states corresponding to the most important principal components, and correction factors are applied to approximate radiation fields. Kopparla et al. [2015, in preparation] extended the PCA method to a broadband spectral region from the ultraviolet to the shortwave infrared (0.3-3 micron), accounting for major gas absorptions in this region. Here, we apply the PCA method to a some typical (exo-)planetary retrieval problems. Comparisons between the new model, called Universal Principal Component Analysis Radiative Transfer (UPCART) model, two-stream models and line-by-line RT models are performed, for spectral radiances, spectral fluxes and broadband fluxes. Each of these are calculated at the top of the atmosphere for several scenarios with varying aerosol types, extinction and scattering optical depth profiles, and stellar and viewing geometries. We demonstrate that very accurate radiance and flux estimates can be obtained, with better than 1% accuracy in all spectral regions and better than 0.1% in most cases, as compared to a numerically exact line-by-line RT model. The accuracy is enhanced when the results are convolved to typical instrument resolutions. The operational speed and accuracy of UPCART can be further improved by optimizing binning schemes and parallelizing the codes, work

  19. Molecular Dynamics in Mixed Solvents Reveals Protein-Ligand Interactions, Improves Docking, and Allows Accurate Binding Free Energy Predictions.

    PubMed

    Arcon, Juan Pablo; Defelipe, Lucas A; Modenutti, Carlos P; López, Elias D; Alvarez-Garcia, Daniel; Barril, Xavier; Turjanski, Adrián G; Martí, Marcelo A

    2017-03-31

    One of the most important biological processes at the molecular level is the formation of protein-ligand complexes. Therefore, determining their structure and underlying key interactions is of paramount relevance and has direct applications in drug development. Because of its low cost relative to its experimental sibling, molecular dynamics (MD) simulations in the presence of different solvent probes mimicking specific types of interactions have been increasingly used to analyze protein binding sites and reveal protein-ligand interaction hot spots. However, a systematic comparison of different probes and their real predictive power from a quantitative and thermodynamic point of view is still missing. In the present work, we have performed MD simulations of 18 different proteins in pure water as well as water mixtures of ethanol, acetamide, acetonitrile and methylammonium acetate, leading to a total of 5.4 μs simulation time. For each system, we determined the corresponding solvent sites, defined as space regions adjacent to the protein surface where the probability of finding a probe atom is higher than that in the bulk solvent. Finally, we compared the identified solvent sites with 121 different protein-ligand complexes and used them to perform molecular docking and ligand binding free energy estimates. Our results show that combining solely water and ethanol sites allows sampling over 70% of all possible protein-ligand interactions, especially those that coincide with ligand-based pharmacophoric points. Most important, we also show how the solvent sites can be used to significantly improve ligand docking in terms of both accuracy and precision, and that accurate predictions of ligand binding free energies, along with relative ranking of ligand affinity, can be performed.

  20. Entropy in statistical energy analysis.

    PubMed

    Le Bot, Alain

    2009-03-01

    In this paper, the second principle of thermodynamics is discussed in the framework of statistical energy analysis (SEA). It is shown that the "vibrational entropy" and the "vibrational temperature" of sub-systems only depend on the vibrational energy and the number of resonant modes. A SEA system can be described as a thermodynamic system slightly out of equilibrium. In steady-state condition, the entropy exchanged with exterior by sources and dissipation exactly balances the production of entropy by irreversible processes at interface between SEA sub-systems.

  1. Extended Adaptive Biasing Force Algorithm. An On-the-Fly Implementation for Accurate Free-Energy Calculations.

    PubMed

    Fu, Haohao; Shao, Xueguang; Chipot, Christophe; Cai, Wensheng

    2016-08-09

    Proper use of the adaptive biasing force (ABF) algorithm in free-energy calculations needs certain prerequisites to be met, namely, that the Jacobian for the metric transformation and its first derivative be available and the coarse variables be independent and fully decoupled from any holonomic constraint or geometric restraint, thereby limiting singularly the field of application of the approach. The extended ABF (eABF) algorithm circumvents these intrinsic limitations by applying the time-dependent bias onto a fictitious particle coupled to the coarse variable of interest by means of a stiff spring. However, with the current implementation of eABF in the popular molecular dynamics engine NAMD, a trajectory-based post-treatment is necessary to derive the underlying free-energy change. Usually, such a posthoc analysis leads to a decrease in the reliability of the free-energy estimates due to the inevitable loss of information, as well as to a drop in efficiency, which stems from substantial read-write accesses to file systems. We have developed a user-friendly, on-the-fly code for performing eABF simulations within NAMD. In the present contribution, this code is probed in eight illustrative examples. The performance of the algorithm is compared with traditional ABF, on the one hand, and the original eABF implementation combined with a posthoc analysis, on the other hand. Our results indicate that the on-the-fly eABF algorithm (i) supplies the correct free-energy landscape in those critical cases where the coarse variables at play are coupled to either each other or to geometric restraints or holonomic constraints, (ii) greatly improves the reliability of the free-energy change, compared to the outcome of a posthoc analysis, and (iii) represents a negligible additional computational effort compared to regular ABF. Moreover, in the proposed implementation, guidelines for choosing two parameters of the eABF algorithm, namely the stiffness of the spring and the mass

  2. An Accurate Quartic Force Field, Fundamental Frequencies, and Binding Energy for the High Energy Density Material T(d)N4

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Martin, Jan M. L.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    The CCSD(T) method has been used to compute a highly accurate quartic force field and fundamental frequencies for all N-14 and N-15 isotopomers of the high energy density material T(sub d)N(sub 4). The computed fundamental frequencies show beyond doubt that the bands observed in a matrix isolation experiment by Radziszewski and coworkers are not due to different isotopomers of T(sub d)N(sub 4). The most sophisticated thermochemical calculations to date yield a N(sub 4) -> 2N(sub 2) heat of reaction of 182.22 +/- 0.5 kcal/mol at 0 K (180.64 +/- 0.5 at 298 K). It is hoped that the data reported herein will aid in the ultimate detection of T(sub d)N(sub 4).

  3. An analysis of the correlation energy contribution to the interaction energy of inert gas dimers.

    PubMed

    Snook, Ian; Per, Manolo C; Russo, Salvy P

    2008-10-28

    An accurate description of electron correlation is essential for the calculation of interaction energies in cases where dispersion energy is a major component, for example, for the rare gas atoms, physisorption on graphite, and graphene-graphene interactions. Such calculations are computationally demanding using supermolecule methods and the energies calculated lack a simple, physical interpretation. Alternatively density functional theories (DFTs) may be used to give an approximate estimate of the correlation energy. However, the physical nature of this DFT estimate of electron correlation energy is not well understood and, in fact, most current DFT methods do not describe dispersion energy at all. Hence, an analysis of the correlation energy contribution to interaction energies where dispersion energy is important is needed. In order to do this we provide an analysis of the correlation energy contribution to the potential energy curves of He(2), Ne(2), and Ar(2) in terms of the Hartree-Fock (HF) interaction term DeltaE(int) (HF), a dispersion energy term E(disp) and an electron correlation term DeltaE(int) (C). DeltaE(int) (C) includes all other correlation energy effects besides E(disp) and is shown to be repulsive, of a similar short range character to, but of smaller magnitude than DeltaE(int) (HF). This analysis was used to develop a theoretical model which gives a very good estimate of the potential energy wells for He(2), Ne(2), Ar(2), HeNe, HeAr, and NeAr.

  4. Current work in energy analysis

    SciTech Connect

    1998-03-01

    This report describes the work performed at Berkeley Lab most recently. One of the Labs accomplishments is the publication of Scenarios of US Carbon Reductions, an analysis of the potential of energy technologies to reduce carbon emissions in the US. This analysis is described and played a key role in shaping the US position on climate change in the Kyoto Protocol negotiations. The Labs participation in the fundamental characterization of the climate change issue by the IPCC is described. Described also is a study of leaking electricity, which is stimulating an international campaign for a one-watt ceiling for standby electricity losses from appliances. This ceiling has the potential to save two-thirds of the 5% of US residential electricity currently expended on standby losses. The 54 vignettes contained in the report summarize results of research activities ranging in scale from calculating the efficacy of individual lamp ballasts to estimating the cost-effectiveness of the national Energy Star{reg_sign} labeling program, and ranging in location from a scoping study of energy-efficiency market transformation in California to development of an energy-efficiency project in the auto parts industry in Shandong Province, China.

  5. High energy beam lifetime analysis

    SciTech Connect

    Howell, R.H.; Sterne, P.A.; Hartley, J.; Cowan, T.E.

    1997-05-01

    We have developed a positron lifetime defect analysis capability based on a 3 MeV electrostatic accelerator. The high energy beam lifetime spectrometer is operational with a 60 mCi {sup 22}Na source providing a current of 7 10{sup 5} positrons per second. Lifetime data are derived from a thin plastic transmission detector providing an implantation time and a BaF{sub 2} detector to determine the annihilation time. Positron lifetime analysis is performed with a 3 MeV positron beam on thick sample specimens at counting rates in excess of 2000 per second. The instrument is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements.

  6. Globally accurate potential energy surface for the ground-state HCS(X2A′) and its use in reaction dynamics

    PubMed Central

    Song, Yu-Zhi; Zhang, Lu-Lu; Gao, Shou-Bao; Meng, Qing-Tian

    2016-01-01

    A globally accurate many-body expansion potential energy surface is reported for HCS(X2A′) by fitting a wealth of accurate ab initio energies calculated at the multireference configuration interaction level using aug-cc-pVQZ and aug-cc-pV5Z basis sets via extrapolation to the complete basis set limit. The topographical features of the present potential energy surface are examined in detail and is in good agreement with the raw ab initio results, as well as other theoretical results available in literatures. By utilizing the potential energy surface of HCS(X2A′), the dynamic studies of the C(3P) + SH(X2Π) → H(2S) + CS(X1∑+) reaction has been carried out using quasi-classical trajectory method. PMID:27898106

  7. Revisit to three-dimensional percolation theory: Accurate analysis for highly stretchable conductive composite materials

    PubMed Central

    Kim, Sangwoo; Choi, Seongdae; Oh, Eunho; Byun, Junghwan; Kim, Hyunjong; Lee, Byeongmoon; Lee, Seunghwan; Hong, Yongtaek

    2016-01-01

    A percolation theory based on variation of conductive filler fraction has been widely used to explain the behavior of conductive composite materials under both small and large deformation conditions. However, it typically fails in properly analyzing the materials under the large deformation since the assumption may not be valid in such a case. Therefore, we proposed a new three-dimensional percolation theory by considering three key factors: nonlinear elasticity, precisely measured strain-dependent Poisson’s ratio, and strain-dependent percolation threshold. Digital image correlation (DIC) method was used to determine actual Poisson’s ratios at various strain levels, which were used to accurately estimate variation of conductive filler volume fraction under deformation. We also adopted strain-dependent percolation threshold caused by the filler re-location with deformation. When three key factors were considered, electrical performance change was accurately analyzed for composite materials with both isotropic and anisotropic mechanical properties. PMID:27694856

  8. Revisit to three-dimensional percolation theory: Accurate analysis for highly stretchable conductive composite materials

    NASA Astrophysics Data System (ADS)

    Kim, Sangwoo; Choi, Seongdae; Oh, Eunho; Byun, Junghwan; Kim, Hyunjong; Lee, Byeongmoon; Lee, Seunghwan; Hong, Yongtaek

    2016-10-01

    A percolation theory based on variation of conductive filler fraction has been widely used to explain the behavior of conductive composite materials under both small and large deformation conditions. However, it typically fails in properly analyzing the materials under the large deformation since the assumption may not be valid in such a case. Therefore, we proposed a new three-dimensional percolation theory by considering three key factors: nonlinear elasticity, precisely measured strain-dependent Poisson’s ratio, and strain-dependent percolation threshold. Digital image correlation (DIC) method was used to determine actual Poisson’s ratios at various strain levels, which were used to accurately estimate variation of conductive filler volume fraction under deformation. We also adopted strain-dependent percolation threshold caused by the filler re-location with deformation. When three key factors were considered, electrical performance change was accurately analyzed for composite materials with both isotropic and anisotropic mechanical properties.

  9. A Technique Using Calibrated Photography and Photoshop for Accurate Shade Analysis and Communication.

    PubMed

    McLaren, Edward A; Figueira, Johan; Goldstein, Ronald E

    2017-02-01

    This article reviews the critical aspects of controlling the shade-taking environment and discusses various modalities introduced throughout the years to acquire and communicate shade information. Demonstrating a highly calibrated digital photographic technique for capturing shade information, this article shows how to use Photoshop® to standardize images and extract color information from the tooth and shade tab for use by a ceramist for an accurate shade-matching restoration.

  10. The utility of accurate mass and LC elution time information in the analysis of complex proteomes

    SciTech Connect

    Norbeck, Angela D.; Monroe, Matthew E.; Adkins, Joshua N.; Anderson, Kevin K.; Daly, Don S.; Smith, Richard D.

    2005-08-01

    Theoretical tryptic digests of all predicted proteins from the genomes of three organisms of varying complexity were evaluated for specificity and possible utility of combined peptide accurate mass and predicted LC normalized elution time (NET) information. The uniqueness of each peptide was evaluated using its combined mass (+/- 5 ppm and 1 ppm) and NET value (no constraint, +/- 0.05 and 0.01 on a 0-1 NET scale). The set of peptides both underestimates actual biological complexity due to the lack of specific modifications, and overestimates the expected complexity since many proteins will not be present in the sample or observable on the mass spectrometer because of dynamic range limitations. Once a peptide is identified from an LCMS/MS experiment, its mass and elution time is representative of a unique fingerprint for that peptide. The uniqueness of that fingerprint in comparison to that for the other peptides present is indicative of the ability to confidently identify that peptide based on accurate mass and NET measurements. These measurements can be made using HPLC coupled with high resolution MS in a high-throughput manner. Results show that for organisms with comparatively small proteomes, such as Deinococcus radiodurans, modest mass and elution time accuracies are generally adequate for peptide identifications. For more complex proteomes, increasingly accurate easurements are required. However, the majority of proteins should be uniquely identifiable by using LC-MS with mass accuracies within +/- 1 ppm and elution time easurements within +/- 0.01 NET.

  11. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the F(-) + CH3F SN2 and proton-abstraction reactions.

    PubMed

    Szabó, István; Telekes, Hajnalka; Czakó, Gábor

    2015-06-28

    We develop a full-dimensional global analytical potential energy surface (PES) for the F(-) + CH3F reaction by fitting about 50 000 energy points obtained by an explicitly correlated composite method based on the second-order Møller-Plesset perturbation-F12 and coupled-cluster singles, doubles, and perturbative triples-F12a methods and the cc-pVnZ-F12 [n = D, T] basis sets. The PES accurately describes the (a) back-side attack Walden inversion mechanism involving the pre- and post-reaction (b) ion-dipole and (c) hydrogen-bonded complexes, the configuration-retaining (d) front-side attack and (e) double-inversion substitution pathways, as well as (f) the proton-abstraction channel. The benchmark quality relative energies of all the important stationary points are computed using the focal-point analysis (FPA) approach considering electron correlation up to coupled-cluster singles, doubles, triples, and perturbative quadruples method, extrapolation to the complete basis set limit, core-valence correlation, and scalar relativistic effects. The FPA classical(adiabatic) barrier heights of (a), (d), and (e) are -0.45(-0.61), 46.07(45.16), and 29.18(26.07) kcal mol(-1), respectively, the dissociation energies of (b) and (c) are 13.81(13.56) and 13.73(13.52) kcal mol(-1), respectively, and the endothermicity of (f) is 42.54(38.11) kcal mol(-1). Quasiclassical trajectory computations of cross sections, scattering (θ) and initial attack (α) angle distributions, as well as translational and internal energy distributions are performed for the F(-) + CH3F(v = 0) reaction using the new PES. Apart from low collision energies (Ecoll), the SN2 excitation function is nearly constant, the abstraction cross sections rapidly increase with Ecoll from a threshold of ∼40 kcal mol(-1), and retention trajectories via double inversion are found above Ecoll = ∼ 30 kcal mol(-1), and at Ecoll = ∼ 50 kcal mol(-1), the front-side attack cross sections start to increase very rapidly. At

  12. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the F- + CH3F SN2 and proton-abstraction reactions

    NASA Astrophysics Data System (ADS)

    Szabó, István; Telekes, Hajnalka; Czakó, Gábor

    2015-06-01

    We develop a full-dimensional global analytical potential energy surface (PES) for the F- + CH3F reaction by fitting about 50 000 energy points obtained by an explicitly correlated composite method based on the second-order Møller-Plesset perturbation-F12 and coupled-cluster singles, doubles, and perturbative triples-F12a methods and the cc-pVnZ-F12 [n = D, T] basis sets. The PES accurately describes the (a) back-side attack Walden inversion mechanism involving the pre- and post-reaction (b) ion-dipole and (c) hydrogen-bonded complexes, the configuration-retaining (d) front-side attack and (e) double-inversion substitution pathways, as well as (f) the proton-abstraction channel. The benchmark quality relative energies of all the important stationary points are computed using the focal-point analysis (FPA) approach considering electron correlation up to coupled-cluster singles, doubles, triples, and perturbative quadruples method, extrapolation to the complete basis set limit, core-valence correlation, and scalar relativistic effects. The FPA classical(adiabatic) barrier heights of (a), (d), and (e) are -0.45(-0.61), 46.07(45.16), and 29.18(26.07) kcal mol-1, respectively, the dissociation energies of (b) and (c) are 13.81(13.56) and 13.73(13.52) kcal mol-1, respectively, and the endothermicity of (f) is 42.54(38.11) kcal mol-1. Quasiclassical trajectory computations of cross sections, scattering (θ) and initial attack (α) angle distributions, as well as translational and internal energy distributions are performed for the F- + CH3F(v = 0) reaction using the new PES. Apart from low collision energies (Ecoll), the SN2 excitation function is nearly constant, the abstraction cross sections rapidly increase with Ecoll from a threshold of ˜40 kcal mol-1, and retention trajectories via double inversion are found above Ecoll = ˜ 30 kcal mol-1, and at Ecoll = ˜ 50 kcal mol-1, the front-side attack cross sections start to increase very rapidly. At low Ecoll, the

  13. Clean Energy Manufacturing Analysis Center (CEMAC)

    SciTech Connect

    2015-12-01

    The U.S. Department of Energy's Clean Energy Manufacturing Analysis Center (CEMAC) provides objective analysis and up-to-date data on global supply chains and manufacturing of clean energy technologies. Policymakers and industry leaders seek CEMAC insights to inform choices to promote economic growth and the transition to a clean energy economy.

  14. Asymptotic modal analysis and statistical energy analysis

    NASA Technical Reports Server (NTRS)

    Dowell, Earl H.

    1992-01-01

    Asymptotic Modal Analysis (AMA) is a method which is used to model linear dynamical systems with many participating modes. The AMA method was originally developed to show the relationship between statistical energy analysis (SEA) and classical modal analysis (CMA). In the limit of a large number of modes of a vibrating system, the classical modal analysis result can be shown to be equivalent to the statistical energy analysis result. As the CMA result evolves into the SEA result, a number of systematic assumptions are made. Most of these assumptions are based upon the supposition that the number of modes approaches infinity. It is for this reason that the term 'asymptotic' is used. AMA is the asymptotic result of taking the limit of CMA as the number of modes approaches infinity. AMA refers to any of the intermediate results between CMA and SEA, as well as the SEA result which is derived from CMA. The main advantage of the AMA method is that individual modal characteristics are not required in the model or computations. By contrast, CMA requires that each modal parameter be evaluated at each frequency. In the latter, contributions from each mode are computed and the final answer is obtained by summing over all the modes in the particular band of interest. AMA evaluates modal parameters only at their center frequency and does not sum the individual contributions from each mode in order to obtain a final result. The method is similar to SEA in this respect. However, SEA is only capable of obtaining spatial averages or means, as it is a statistical method. Since AMA is systematically derived from CMA, it can obtain local spatial information as well.

  15. How accurately are climatological characteristics and surface water and energy balances represented for the Colombian Caribbean Catchment Basin?

    NASA Astrophysics Data System (ADS)

    Hoyos, Isabel; Baquero-Bernal, Astrid; Hagemann, Stefan

    2013-09-01

    precipitation is better represented by Delaware. Among the three datasets that permit an analysis of surface water and energy balances (REMO, ERA-40, and NCEP/NCAR), REMO best demonstrates the closure property of the surface water balance within the basin, while NCEP/NCAR does not demonstrate this property well. The three datasets represent the energy balance fairly well, although some inconsistencies were found in the individual balance components for NCEP/NCAR.

  16. Is the SenseWear Armband accurate enough to quantify and estimate energy expenditure in healthy adults?

    PubMed Central

    Hernández-Vicente, Adrián; Pérez-Isaac, Raúl; Santín-Medeiros, Fernanda; Cristi-Montero, Carlos; Casajús, Jose Antonio; Garatachea, Nuria

    2017-01-01

    Background The SenseWear Armband (SWA) is a monitor that can be used to estimate energy expenditure (EE); however, it has not been validated in healthy adults. The objective of this paper was to study the validity of the SWA for quantifying EE levels. Methods Twenty-three healthy adults (age 40–55 years, mean: 48±3.42 years) performed different types of standardized physical activity (PA) for 10 minutes (rest, walking at 3 and 5 km·h-1, running at 7 and 9 km·h-1, and sitting/standing at a rate of 30 cycle·min-1). Participants wore the SWA on their right arm, and their EE was measured by indirect calorimetry (IC) the gold standard. Results There were significant differences between the SWA and IC, except in the group that ran at 9 km·h-1 (>9 METs). Bland-Altman analysis showed a BIAS of 1.56 METs (±1.83 METs) and limits of agreement (LOA) at 95% of −2.03 to 5.16 METs. There were indications of heteroscedasticity (R2 =0.03; P<0.05). Analysis of the receiver operating characteristic (ROC) curves showed that the SWA seems to be not sensitive enough to estimate the level of EE at highest intensities. Conclusions The SWA is not as precise in estimating EE as IC, but it could be a useful tool to determine levels of EE at low intensities. PMID:28361062

  17. The utility of accurate mass and LC elution time information in the analysis of complex proteomes

    PubMed Central

    Norbeck, Angela D.; Monroe, Matthew E.; Adkins, Joshua N.; Smith, Richard D.

    2007-01-01

    Theoretical tryptic digests of all predicted proteins from the genomes of three organisms of varying complexity were evaluated for specificity and possible utility of combined peptide accurate mass and predicted LC normalized elution time (NET) information. The uniqueness of each peptide was evaluated using its combined mass (+/− 5 ppm and 1 ppm) and NET value (no constraint, +/− 0.05 and 0.01 on a 0–1 NET scale). The set of peptides both underestimates actual biological complexity due to the lack of specific modifications, and overestimates the expected complexity since many proteins will not be present in the sample or observable on the mass spectrometer because of dynamic range limitations. Once a peptide is identified from an LC-MS/MS experiment, its mass and elution time is representative of a unique fingerprint for that peptide. The uniqueness of that fingerprint in comparison to that for the other peptides present is indicative of the ability to confidently identify that peptide based on accurate mass and NET measurements. These measurements can be made using HPLC coupled with high resolution MS in a high-throughput manner. Results show that for organisms with comparatively small proteomes, such as Deinococcus radiodurans, modest mass and elution time accuracies are generally adequate for peptide identifications. For more complex proteomes, increasingly accurate measurements are required. However, the majority of proteins should be uniquely identifiable by using LC-MS with mass accuracies within +/− 1 ppm and elution time measurements within +/− 0.01 NET. PMID:15979333

  18. Time-Accurate Simulations and Acoustic Analysis of Slat Free-Shear-Layer. Part 2

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Singer, Bart A.; Lockard, David P.

    2002-01-01

    Unsteady computational simulations of a multi-element, high-lift configuration are performed. Emphasis is placed on accurate spatiotemporal resolution of the free shear layer in the slat-cove region. The excessive dissipative effects of the turbulence model, so prevalent in previous simulations, are circumvented by switching off the turbulence-production term in the slat cove region. The justifications and physical arguments for taking such a step are explained in detail. The removal of this excess damping allows the shear layer to amplify large-scale structures, to achieve a proper non-linear saturation state, and to permit vortex merging. The large-scale disturbances are self-excited, and unlike our prior fully turbulent simulations, no external forcing of the shear layer is required. To obtain the farfield acoustics, the Ffowcs Williams and Hawkings equation is evaluated numerically using the simulated time-accurate flow data. The present comparison between the computed and measured farfield acoustic spectra shows much better agreement for the amplitude and frequency content than past calculations. The effect of the angle-of-attack on the slat's flow features radiated acoustic field are also simulated presented.

  19. Analysis of hydraulic fracturing flowback and produced waters using accurate mass: identification of ethoxylated surfactants.

    PubMed

    Thurman, E Michael; Ferrer, Imma; Blotevogel, Jens; Borch, Thomas

    2014-10-07

    Two series of ethylene oxide (EO) surfactants, polyethylene glycols (PEGs from EO3 to EO33) and linear alkyl ethoxylates (LAEs C-9 to C-15 with EO3-EO28), were identified in hydraulic fracturing flowback and produced water using a new application of the Kendrick mass defect and liquid chromatography/quadrupole-time-of-flight mass spectrometry. The Kendrick mass defect differentiates the proton, ammonium, and sodium adducts in both singly and doubly charged forms. A structural model of adduct formation is presented, and binding constants are calculated, which is based on a spherical cagelike conformation, where the central cation (NH4(+) or Na(+)) is coordinated with ether oxygens. A major purpose of the study was the identification of the ethylene oxide (EO) surfactants and the construction of a database with accurate masses and retention times in order to unravel the mass spectral complexity of surfactant mixtures used in hydraulic fracturing fluids. For example, over 500 accurate mass assignments are made in a few seconds of computer time, which then is used as a fingerprint chromatogram of the water samples. This technique is applied to a series of flowback and produced water samples to illustrate the usefulness of ethoxylate "fingerprinting", in a first application to monitor water quality that results from fluids used in hydraulic fracturing.

  20. Application of the energy reassignment method to measure accurate Rayleigh and Love wave group velocities from ambient seismic noise cross-correlations

    NASA Astrophysics Data System (ADS)

    Witek, M.; Kang, T. S.; van der Lee, S.

    2015-12-01

    We have collected three-component data from 122 Korean accelerometer stations for the month of December in 2014. We apply similar techniques described by Zha et al. (2013) to retrieve accurate station orientation angles, in order to rotate the horizontal component data into the radial and transverse frame of reference, and for subsequent measurement of Love wave group velocity dispersion. We simultaneously normalize all three components of a daily noise record via the frequency-time normalization (FTN) method. Each component is divided by the average signal envelope in an effort to retain relative amplitude information between all three components. Station orientations are found by a grid search for the orientation azimuth which maximizes the coherency between the radial-vertical cross-correlation and the Hilbert transformed vertical-vertical cross-correlation. After measuring orientation angles, we cross-correlate and rotate the data. Typically, the group velocity dispersion curves are measured using the frequency time analysis technique (FTAN), effectively producing spectrograms with significant uncertainty in the time-frequency plane. The spectrogram approach retains only the amplitude information of the short-time Fourier transform (STFT). However, Kodera et al (1976) show that by taking into account the phase information, the concepts of instantaneous frequency and group-time delay can be used to compute the first moment of the signal power in the frequency and time domains. During energy reassignment, the signal power calculated using the STFT at a point (t0,f0t_0, f_0) is reassigned to the location of the first moment (t^g,f^ihat{t}_g,hat{f}_i), where t^ghat{t}_g is the group-time delay and f^ihat{f}_i is the instantaneous frequency. We apply the method of energy reassignment to produce precise Rayleigh and Love wave group velocity measurements in the frequency range 0.1 - 1.0 Hz. Tests on synthetic data show more accurate retrieval of group velocities at

  1. Colocalization analysis in fluorescence micrographs: verification of a more accurate calculation of pearson's correlation coefficient.

    PubMed

    Barlow, Andrew L; Macleod, Alasdair; Noppen, Samuel; Sanderson, Jeremy; Guérin, Christopher J

    2010-12-01

    One of the most routine uses of fluorescence microscopy is colocalization, i.e., the demonstration of a relationship between pairs of biological molecules. Frequently this is presented simplistically by the use of overlays of red and green images, with areas of yellow indicating colocalization of the molecules. Colocalization data are rarely quantified and can be misleading. Our results from both synthetic and biological datasets demonstrate that the generation of Pearson's correlation coefficient between pairs of images can overestimate positive correlation and fail to demonstrate negative correlation. We have demonstrated that the calculation of a thresholded Pearson's correlation coefficient using only intensity values over a determined threshold in both channels produces numerical values that more accurately describe both synthetic datasets and biological examples. Its use will bring clarity and accuracy to colocalization studies using fluorescent microscopy.

  2. Easy Leaf Area: Automated digital image analysis for rapid and accurate measurement of leaf area1

    PubMed Central

    Easlon, Hsien Ming; Bloom, Arnold J.

    2014-01-01

    • Premise of the study: Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. • Methods and Results: Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. • Conclusions: Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images. PMID:25202639

  3. Accurate size measurement of monosize calibration spheres by differential mobility analysis

    SciTech Connect

    Mulholland, George W.; Fernandez, Marco

    1998-11-24

    A differential mobility analyzer was used to measure the mean particle size of three monosize suspensions of polystyrene spheres in water. Key features of the experiment to minimize the uncertainty in the results include developing a recirculating flow to ensure equal flows into and out of the classifier, an accurate divider circuit for calibrating the electrode voltage, and use of the 100.7 nm NIST SRM for calibrating the flow of the classifier. The measured average sizes and expanded uncertainties with a coverage factor of 2 are 92.4 nm{+-}1.1 nm, 126.9 nm{+-}1.4 nm, and 217.7 nm{+-}3.4 nm. These calibration sizes were characterized by NIST to improve the calibration of scanning surface inspection systems.

  4. Importance of accurate spectral simulations for the analysis of terahertz spectra: citric acid anhydrate and monohydrate.

    PubMed

    King, Matthew D; Davis, Eric A; Smith, Tiffany M; Korter, Timothy M

    2011-10-13

    The terahertz (THz) spectra of crystalline solids are typically uniquely sensitive to the molecular packing configurations, allowing for the detection of polymorphs and hydrates by THz spectroscopic techniques. It is possible, however, that coincident absorptions may be observed between related crystal forms, in which case careful assessment of the lattice vibrations of each system must be performed. Presented here is a THz spectroscopic investigation of citric acid in its anhydrous and monohydrate phases. Remarkably similar features were observed in the THz spectra of both systems, requiring the accurate calculation of the low-frequency vibrational modes by solid-state density functional theory to determine the origins of these spectral features. The results of the simulations demonstrate the necessity of reliable and rigorous methods for THz vibrational modes to ensure the proper evaluation of the THz spectra of molecular solids.

  5. Methods for accurate analysis of galaxy clustering on non-linear scales

    NASA Astrophysics Data System (ADS)

    Vakili, Mohammadjavad

    2017-01-01

    Measurements of galaxy clustering with the low-redshift galaxy surveys provide sensitive probe of cosmology and growth of structure. Parameter inference with galaxy clustering relies on computation of likelihood functions which requires estimation of the covariance matrix of the observables used in our analyses. Therefore, accurate estimation of the covariance matrices serves as one of the key ingredients in precise cosmological parameter inference. This requires generation of a large number of independent galaxy mock catalogs that accurately describe the statistical distribution of galaxies in a wide range of physical scales. We present a fast method based on low-resolution N-body simulations and approximate galaxy biasing technique for generating mock catalogs. Using a reference catalog that was created using the high resolution Big-MultiDark N-body simulation, we show that our method is able to produce catalogs that describe galaxy clustering at a percentage-level accuracy down to highly non-linear scales in both real-space and redshift-space.In most large-scale structure analyses, modeling of galaxy bias on non-linear scales is performed assuming a halo model. Clustering of dark matter halos has been shown to depend on halo properties beyond mass such as halo concentration, a phenomenon referred to as assembly bias. Standard large-scale structure studies assume that halo mass alone is sufficient in characterizing the connection between galaxies and halos. However, modeling of galaxy bias can face systematic effects if the number of galaxies are correlated with other halo properties. Using the Small MultiDark-Planck high resolution N-body simulation and the clustering measurements of Sloan Digital Sky Survey DR7 main galaxy sample, we investigate the extent to which the dependence of galaxy bias on halo concentration can improve our modeling of galaxy clustering.

  6. Asymptotic modal analysis and statistical energy analysis

    NASA Technical Reports Server (NTRS)

    Dowell, Earl H.

    1988-01-01

    Statistical Energy Analysis (SEA) is defined by considering the asymptotic limit of Classical Modal Analysis, an approach called Asymptotic Modal Analysis (AMA). The general approach is described for both structural and acoustical systems. The theoretical foundation is presented for structural systems, and experimental verification is presented for a structural plate responding to a random force. Work accomplished subsequent to the grant initiation focusses on the acoustic response of an interior cavity (i.e., an aircraft or spacecraft fuselage) with a portion of the wall vibrating in a large number of structural modes. First results were presented at the ASME Winter Annual Meeting in December, 1987, and accepted for publication in the Journal of Vibration, Acoustics, Stress and Reliability in Design. It is shown that asymptotically as the number of acoustic modes excited becomes large, the pressure level in the cavity becomes uniform except at the cavity boundaries. However, the mean square pressure at the cavity corner, edge and wall is, respectively, 8, 4, and 2 times the value in the cavity interior. Also it is shown that when the portion of the wall which is vibrating is near a cavity corner or edge, the response is significantly higher.

  7. A versatile phenomenological model for the S-shaped temperature dependence of photoluminescence energy for an accurate determination of the exciton localization energy in bulk and quantum well structures

    NASA Astrophysics Data System (ADS)

    Dixit, V. K.; Porwal, S.; Singh, S. D.; Sharma, T. K.; Ghosh, Sandip; Oak, S. M.

    2014-02-01

    Temperature dependence of the photoluminescence (PL) peak energy of bulk and quantum well (QW) structures is studied by using a new phenomenological model for including the effect of localized states. In general an anomalous S-shaped temperature dependence of the PL peak energy is observed for many materials which is usually associated with the localization of excitons in band-tail states that are formed due to potential fluctuations. Under such conditions, the conventional models of Varshni, Viña and Passler fail to replicate the S-shaped temperature dependence of the PL peak energy and provide inconsistent and unrealistic values of the fitting parameters. The proposed formalism persuasively reproduces the S-shaped temperature dependence of the PL peak energy and provides an accurate determination of the exciton localization energy in bulk and QW structures along with the appropriate values of material parameters. An example of a strained InAs0.38P0.62/InP QW is presented by performing detailed temperature and excitation intensity dependent PL measurements and subsequent in-depth analysis using the proposed model. Versatility of the new formalism is tested on a few other semiconductor materials, e.g. GaN, nanotextured GaN, AlGaN and InGaN, which are known to have a significant contribution from the localized states. A quantitative evaluation of the fractional contribution of the localized states is essential for understanding the temperature dependence of the PL peak energy of bulk and QW well structures having a large contribution of the band-tail states.

  8. Accurate high level ab initio-based global potential energy surface and dynamics calculations for ground state of CH2(+).

    PubMed

    Li, Y Q; Zhang, P Y; Han, K L

    2015-03-28

    A global many-body expansion potential energy surface is reported for the electronic ground state of CH2 (+) by fitting high level ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pV6Z basis set. The topographical features of the new global potential energy surface are examined in detail and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. In turn, in order to validate the potential energy surface, a test theoretical study of the reaction CH(+)(X(1)Σ(+))+H((2)S)→C(+)((2)P)+H2(X(1)Σg (+)) has been carried out with the method of time dependent wavepacket on the title potential energy surface. The total integral cross sections and the rate coefficients have been calculated; the results determined that the new potential energy surface can both be recommended for dynamics studies of any type and as building blocks for constructing the potential energy surfaces of larger C(+)/H containing systems.

  9. San Carlos Apache Tribe - Energy Organizational Analysis

    SciTech Connect

    Rapp, James; Albert, Steve

    2012-04-01

    The San Carlos Apache Tribe (SCAT) was awarded $164,000 in late-2011 by the U.S. Department of Energy (U.S. DOE) Tribal Energy Program's "First Steps Toward Developing Renewable Energy and Energy Efficiency on Tribal Lands" Grant Program. This grant funded:  The analysis and selection of preferred form(s) of tribal energy organization (this Energy Organization Analysis, hereinafter referred to as "EOA").  Start-up staffing and other costs associated with the Phase 1 SCAT energy organization.  An intern program.  Staff training.  Tribal outreach and workshops regarding the new organization and SCAT energy programs and projects, including two annual tribal energy summits (2011 and 2012). This report documents the analysis and selection of preferred form(s) of a tribal energy organization.

  10. Scripted Building Energy Modeling and Analysis (Presentation)

    SciTech Connect

    Macumber, D.

    2012-10-01

    Building energy analysis is often time-intensive, error-prone, and non-reproducible. Entire energy analyses can be scripted end-to-end using the OpenStudio Ruby API. Common tasks within an analysis can be automated using OpenStudio Measures. Graphical user interfaces (GUI's) and component libraries reduce time, decrease errors, and improve repeatability in energy modeling.

  11. The ALHAMBRA survey: accurate merger fractions derived by PDF analysis of photometrically close pairs

    NASA Astrophysics Data System (ADS)

    López-Sanjuan, C.; Cenarro, A. J.; Varela, J.; Viironen, K.; Molino, A.; Benítez, N.; Arnalte-Mur, P.; Ascaso, B.; Díaz-García, L. A.; Fernández-Soto, A.; Jiménez-Teja, Y.; Márquez, I.; Masegosa, J.; Moles, M.; Pović, M.; Aguerri, J. A. L.; Alfaro, E.; Aparicio-Villegas, T.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; Del Olmo, A.; González Delgado, R. M.; Husillos, C.; Infante, L.; Martínez, V. J.; Perea, J.; Prada, F.; Quintana, J. M.

    2015-04-01

    Aims: Our goal is to develop and test a novel methodology to compute accurate close-pair fractions with photometric redshifts. Methods: We improved the currently used methodologies to estimate the merger fraction fm from photometric redshifts by (i) using the full probability distribution functions (PDFs) of the sources in redshift space; (ii) including the variation in the luminosity of the sources with z in both the sample selection and the luminosity ratio constrain; and (iii) splitting individual PDFs into red and blue spectral templates to reliably work with colour selections. We tested the performance of our new methodology with the PDFs provided by the ALHAMBRA photometric survey. Results: The merger fractions and rates from the ALHAMBRA survey agree excellently well with those from spectroscopic work for both the general population and red and blue galaxies. With the merger rate of bright (MB ≤ -20-1.1z) galaxies evolving as (1 + z)n, the power-law index n is higher for blue galaxies (n = 2.7 ± 0.5) than for red galaxies (n = 1.3 ± 0.4), confirming previous results. Integrating the merger rate over cosmic time, we find that the average number of mergers per galaxy since z = 1 is Nmred = 0.57 ± 0.05 for red galaxies and Nmblue = 0.26 ± 0.02 for blue galaxies. Conclusions: Our new methodology statistically exploits all the available information provided by photometric redshift codes and yields accurate measurements of the merger fraction by close pairs from using photometric redshifts alone. Current and future photometric surveys will benefit from this new methodology. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie (MPIA) at Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC).The catalogues, probabilities, and figures of the ALHAMBRA close pairs detected in Sect. 5.1 are available at http://https://cloud.iaa.csic.es/alhambra/catalogues/ClosePairs

  12. Dynamics Analysis of Wind Energy Production Development

    NASA Astrophysics Data System (ADS)

    Berg, V. I.; Zakirzakov, A. G.; Gordievskaya, E. F.

    2017-01-01

    The paper presents the analysis of the introduction experience and dynamics development of the world wind energy production. Calculated the amount of wind energy sources investments and the production capacity growth dynamics of the wind turbines. The studies have shown that the introduction dynamics of new wind energy sources is higher than any other energy source.

  13. An integrative variant analysis pipeline for accurate genotype/haplotype inference in population NGS data.

    PubMed

    Wang, Yi; Lu, James; Yu, Jin; Gibbs, Richard A; Yu, Fuli

    2013-05-01

    Next-generation sequencing is a powerful approach for discovering genetic variation. Sensitive variant calling and haplotype inference from population sequencing data remain challenging. We describe methods for high-quality discovery, genotyping, and phasing of SNPs for low-coverage (approximately 5×) sequencing of populations, implemented in a pipeline called SNPTools. Our pipeline contains several innovations that specifically address challenges caused by low-coverage population sequencing: (1) effective base depth (EBD), a nonparametric statistic that enables more accurate statistical modeling of sequencing data; (2) variance ratio scoring, a variance-based statistic that discovers polymorphic loci with high sensitivity and specificity; and (3) BAM-specific binomial mixture modeling (BBMM), a clustering algorithm that generates robust genotype likelihoods from heterogeneous sequencing data. Last, we develop an imputation engine that refines raw genotype likelihoods to produce high-quality phased genotypes/haplotypes. Designed for large population studies, SNPTools' input/output (I/O) and storage aware design leads to improved computing performance on large sequencing data sets. We apply SNPTools to the International 1000 Genomes Project (1000G) Phase 1 low-coverage data set and obtain genotyping accuracy comparable to that of SNP microarray.

  14. High-accurate optical vector analysis based on optical single-sideband modulation

    NASA Astrophysics Data System (ADS)

    Xue, Min; Pan, Shilong

    2016-11-01

    Most of the efforts devoted to the area of optical communications were on the improvement of the optical spectral efficiency. Varies innovative optical devices are thus developed to finely manipulate the optical spectrum. Knowing the spectral responses of these devices, including the magnitude, phase and polarization responses, is of great importance for their fabrication and application. To achieve high-resolution characterization, optical vector analyzers (OVAs) based on optical single-sideband (OSSB) modulation have been proposed and developed. Benefiting from the mature and highresolution microwave technologies, the OSSB-based OVA can potentially achieve a resolution of sub-Hz. However, the accuracy is restricted by the measurement errors induced by the unwanted first-order sideband and the high-order sidebands in the OSSB signal, since electrical-to-optical conversion and optical-to-electrical conversion are essentially required to achieve high-resolution frequency sweeping and extract the magnitude and phase information in the electrical domain. Recently, great efforts have been devoted to improve the accuracy of the OSSB-based OVA. In this paper, the influence of the unwanted-sideband induced measurement errors and techniques for implementing high-accurate OSSB-based OVAs are discussed.

  15. Design of an accurate wireless data logger for vibration analysis with Android interface.

    PubMed

    Blanco, J R; Menéndez, J; Ferrero, F J; Campo, J C; Valledor, M

    2016-12-01

    In this work a new accurate wireless data logger using the Android interface was developed to monitor vibrations at low-cost. The new data logger is completely autonomous and extremely reduced in size. This instrument enables data collection wirelessly and the ability to display it on any tablet or smartphone with operating system Android. The prototype allows the monitoring of any industrial system with minimal investment in material and installation costs. The data logger is capable of making 12.8 kSPS enough to sample up to 5 kHz signals. The basic specification of the data logger includes a high resolution 1-axis piezoelectric accelerometer with a working range of ±30 G. In addition to the acceleration measurements, temperature can also be recorded. The data logger was tested during a 6-month period in industrial environments. The details of the specific hardware and software design are described. The proposed technology can be easily transferred to many other areas of industrial monitoring.

  16. Design of an accurate wireless data logger for vibration analysis with Android interface

    NASA Astrophysics Data System (ADS)

    Blanco, J. R.; Menéndez, J.; Ferrero, F. J.; Campo, J. C.; Valledor, M.

    2016-12-01

    In this work a new accurate wireless data logger using the Android interface was developed to monitor vibrations at low-cost. The new data logger is completely autonomous and extremely reduced in size. This instrument enables data collection wirelessly and the ability to display it on any tablet or smartphone with operating system Android. The prototype allows the monitoring of any industrial system with minimal investment in material and installation costs. The data logger is capable of making 12.8 kSPS enough to sample up to 5 kHz signals. The basic specification of the data logger includes a high resolution 1-axis piezoelectric accelerometer with a working range of ±30 G. In addition to the acceleration measurements, temperature can also be recorded. The data logger was tested during a 6-month period in industrial environments. The details of the specific hardware and software design are described. The proposed technology can be easily transferred to many other areas of industrial monitoring.

  17. An accurate potential energy surface for the F + H2 → HF + H reaction by the coupled-cluster method.

    PubMed

    Chen, Jun; Sun, Zhigang; Zhang, Dong H

    2015-01-14

    A three dimensional potential energy surface for the F + H2 → HF + H reaction has been computed by the spin unrestricted coupled cluster method with singles, doubles, triples, and perturbative quadruples [UCCSDT(2)Q] using the augmented correlation-consistent polarised valence quadruple zeta basis set for the fluorine atom and the correlation-consistent polarised valence quadruple zeta basis set for the hydrogen atom. All the calculations are based on the restricted open-shell Hartree-Fock orbitals, together with the frozen core approximations, and the UCCSD(T)/complete basis set (CBS) correction term was included. The global potential energy surface was calculated by fitting the sampled ab initio points without any scaling factor for the correlation energy part using a neutral network function method. Extensive dynamics calculations have been carried out on the potential energy surface. The reaction rate constants, integral cross sections, product rotational states distribution, and forward and backward scattering as a function of collision energy of the F + HD → HF + D, F + HD → DF + H, and F + H2 reaction, were calculated by the time-independent quantum dynamics scattering theory using the new surface. The satisfactory agreement with the reported experimental observations previously demonstrates the accuracy of the new potential energy surface.

  18. Electrochemical valveless flow microsystems for ultra fast and accurate analysis of total isoflavones with integrated calibration.

    PubMed

    Blasco, Antonio Javier; Crevillén, Agustín González; de la Fuente, Pedro; González, María Cristina; Escarpa, Alberto

    2007-04-01

    A novel strategy integrating methodological calibration and analysis on board on a planar first-generation microfluidics system for the determination of total isoflavones in soy samples is proposed. The analytical strategy is conceptually proposed and successfully demonstrated on the basis of (i) the microchip design (with the possibility to use both reservoirs), (ii) the analytical characteristics of the developed method (statically zero intercept and excellent robustness between calibration slopes, RSDs < 5%), (iii) the irreversible electrochemical behaviour of isoflavone oxidation (no significant electrode fouling effect was observed between calibration and analysis runs) and (iv) the inherent versatility of the electrochemical end-channel configurations (possibility of use different pumping and detection media). Repeatability obtained in both standard (calibration) and real soy samples (analysis) with values of RSD less than 1% for the migration times indicated the stability of electroosmotic flow (EOF) during both integrated operations. The accuracy (an error of less than 6%) is demonstrated for the first time in these microsystems using a documented secondary standard from the Drug Master File (SW/1211/03) as reference material. Ultra fast calibration and analysis of total isoflavones in soy samples was integrated successfully employing 60 s each; enhancing notably the analytical performance of these microdevices with an important decrease in overall analysis times (less than 120 s) and with an increase in accuracy by a factor of 3.

  19. Accurate and noninvasive embryos screening during in vitro fertilization (IVF) assisted by Raman analysis of embryos culture medium Accurate and noninvasive embryos screening during IVF

    NASA Astrophysics Data System (ADS)

    Shen, A. G.; Peng, J.; Zhao, Q. H.; Su, L.; Wang, X. H.; Hu, J. M.; Yang, J.

    2012-04-01

    In combination with morphological evaluation tests, we employ Raman spectroscopy to select higher potential reproductive embryos during in vitro fertilization (IVF) based on chemical composition of embryos culture medium. In this study, 57 Raman spectra are acquired from both higher and lower quality embryos culture medium (ECM) from 10 patients which have been preliminarily confirmed by clinical assay. Data are fit by using a linear combination model of least squares method in which 12 basis spectra represent the chemical features of ECM. The final fitting coefficients provide insight into the chemical compositions of culture medium samples and are subsequently used as criterion to evaluate the quality of embryos. The relative fitting coefficients ratios of sodium pyruvate/albumin and phenylalanine/albumin seem act as key roles in the embryo screening, attaining 85.7% accuracy in comparison with clinical pregnancy. The good results demonstrate that Raman spectroscopy therefore is an important candidate for an accurate and noninvasive screening of higher quality embryos, which potentially decrease the time-consuming clinical trials during IVF.

  20. LUTE (Local Unpruned Tuple Expansion): Accurate Continuously Flexible Protein Design with General Energy Functions and Rigid Rotamer-Like Efficiency.

    PubMed

    Hallen, Mark A; Jou, Jonathan D; Donald, Bruce R

    2016-09-28

    Most protein design algorithms search over discrete conformations and an energy function that is residue-pairwise, that is, a sum of terms that depend on the sequence and conformation of at most two residues. Although modeling of continuous flexibility and of non-residue-pairwise energies significantly increases the accuracy of protein design, previous methods to model these phenomena add a significant asymptotic cost to design calculations. We now remove this cost by modeling continuous flexibility and non-residue-pairwise energies in a form suitable for direct input to highly efficient, discrete combinatorial optimization algorithms such as DEE/A* or branch-width minimization. Our novel algorithm performs a local unpruned tuple expansion (LUTE), which can efficiently represent both continuous flexibility and general, possibly nonpairwise energy functions to an arbitrary level of accuracy using a discrete energy matrix. We show using 47 design calculation test cases that LUTE provides a dramatic speedup in both single-state and multistate continuously flexible designs.

  1. How to Construct More Accurate Student Models: Comparing and Optimizing Knowledge Tracing and Performance Factor Analysis

    ERIC Educational Resources Information Center

    Gong, Yue; Beck, Joseph E.; Heffernan, Neil T.

    2011-01-01

    Student modeling is a fundamental concept applicable to a variety of intelligent tutoring systems (ITS). However, there is not a lot of practical guidance on how to construct and train such models. This paper compares two approaches for student modeling, Knowledge Tracing (KT) and Performance Factors Analysis (PFA), by evaluating their predictive…

  2. Solid rocket booster internal flow analysis by highly accurate adaptive computational methods

    NASA Technical Reports Server (NTRS)

    Huang, C. Y.; Tworzydlo, W.; Oden, J. T.; Bass, J. M.; Cullen, C.; Vadaketh, S.

    1991-01-01

    The primary objective of this project was to develop an adaptive finite element flow solver for simulating internal flows in the solid rocket booster. Described here is a unique flow simulator code for analyzing highly complex flow phenomena in the solid rocket booster. New methodologies and features incorporated into this analysis tool are described.

  3. An accurate density functional theory calculation for electronic excitation energies: the least-squares support vector machine.

    PubMed

    Gao, Ting; Sun, Shi-Ling; Shi, Li-Li; Li, Hui; Li, Hong-Zhi; Su, Zhong-Min; Lu, Ying-Hua

    2009-05-14

    Support vector machines (SVMs), as a novel type of learning machine, has been very successful in pattern recognition and function estimation problems. In this paper we introduce least-squares (LS) SVMs to improve the calculation accuracy of density functional theory. As a demonstration, this combined quantum mechanical calculation with LS-SVM correction approach has been applied to evaluate the electronic excitation energies of 160 organic molecules. The newly introduced LS-SVM approach reduces the root-mean-square deviation of the calculated electronic excitation energies of 160 organic molecules from 0.32 to 0.11 eV for the B3LYP/6-31G(d) calculation. Thus, the LS-SVM correction on top of B3LYP/6-31G(d) is a better method to correct electronic excitation energies and can be used as the approximation of experimental results which are impossible to obtain experimentally.

  4. Numerical simulation and analysis of accurate blood oxygenation measurement by using optical resolution photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Yu, Tianhao; Li, Qian; Li, Lin; Zhou, Chuanqing

    2016-10-01

    Accuracy of photoacoustic signal is the crux on measurement of oxygen saturation in functional photoacoustic imaging, which is influenced by factors such as defocus of laser beam, curve shape of large vessels and nonlinear saturation effect of optical absorption in biological tissues. We apply Monte Carlo model to simulate energy deposition in tissues and obtain photoacoustic signals reaching a simulated focused surface detector to investigate corresponding influence of these factors. We also apply compensation on photoacoustic imaging of in vivo cat cerebral cortex blood vessels, in which signals from different lateral positions of vessels are corrected based on simulation results. And this process on photoacoustic images can improve the smoothness and accuracy of oxygen saturation results.

  5. Whole-House Energy Analysis Procedures for Existing Homes: Preprint

    SciTech Connect

    Hendron, R.

    2006-08-01

    This paper describes a proposed set of guidelines for analyzing the energy savings achieved by a package of retrofits or an extensive rehabilitation of an existing home. It also describes certain field test and audit methods that can help establish accurate building system performance characteristics that are needed for a meaningful simulation of whole-house energy use. Several sets of default efficiency values have been developed for older appliances that cannot be easily tested and for which published specifications are not readily available. These proposed analysis procedures are documented more comprehensively in NREL Technical Report TP-550-38238.

  6. Practical implementation of an accurate method for multilevel design sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc T.

    1987-01-01

    Solution techniques for handling large scale engineering optimization problems are reviewed. Potentials for practical applications as well as their limited capabilities are discussed. A new solution algorithm for design sensitivity is proposed. The algorithm is based upon the multilevel substructuring concept to be coupled with the adjoint method of sensitivity analysis. There are no approximations involved in the present algorithm except the usual approximations introduced due to the discretization of the finite element model. Results from the six- and thirty-bar planar truss problems show that the proposed multilevel scheme for sensitivity analysis is more effective (in terms of computer incore memory and the total CPU time) than a conventional (one level) scheme even on small problems. The new algorithm is expected to perform better for larger problems and its applications on the new generation of computer hardwares with 'parallel processing' capability is very promising.

  7. Accurate and efficient representation of intramolecular energy in ab initio generation of crystal structures. I. Adaptive local approximate models.

    PubMed

    Sugden, Isaac; Adjiman, Claire S; Pantelides, Constantinos C

    2016-12-01

    The global search stage of crystal structure prediction (CSP) methods requires a fine balance between accuracy and computational cost, particularly for the study of large flexible molecules. A major improvement in the accuracy and cost of the intramolecular energy function used in the CrystalPredictor II [Habgood et al. (2015). J. Chem. Theory Comput. 11, 1957-1969] program is presented, where the most efficient use of computational effort is ensured via the use of adaptive local approximate model (LAM) placement. The entire search space of the relevant molecule's conformations is initially evaluated using a coarse, low accuracy grid. Additional LAM points are then placed at appropriate points determined via an automated process, aiming to minimize the computational effort expended in high-energy regions whilst maximizing the accuracy in low-energy regions. As the size, complexity and flexibility of molecules increase, the reduction in computational cost becomes marked. This improvement is illustrated with energy calculations for benzoic acid and the ROY molecule, and a CSP study of molecule (XXVI) from the sixth blind test [Reilly et al. (2016). Acta Cryst. B72, 439-459], which is challenging due to its size and flexibility. Its known experimental form is successfully predicted as the global minimum. The computational cost of the study is tractable without the need to make unphysical simplifying assumptions.

  8. Apparatus for use in rapid and accurate controlled-potential coulometric analysis

    DOEpatents

    Frazzini, Thomas L.; Holland, Michael K.; Pietri, Charles E.; Weiss, Jon R.

    1981-01-01

    An apparatus for controlled-potential coulometric analysis of a solution includes a cell to contain the solution to be analyzed and a plurality of electrodes to contact the solution in the cell. Means are provided to stir the solution and to control the atmosphere above it. A potentiostat connected to the electrodes controls potential differences among the electrodes. An electronic circuit connected to the potentiostat provides analog-to-digital conversion and displays a precise count of charge transfer during a desired chemical process. This count provides a measure of the amount of an unknown substance in the solution.

  9. Advances in Proteomics Data Analysis and Display Using an Accurate Mass and Time Tag Approach

    PubMed Central

    Zimmer, Jennifer S.D.; Monroe, Matthew E.; Qian, Wei-Jun; Smith, Richard D.

    2007-01-01

    Proteomics has recently demonstrated utility in understanding cellular processes on the molecular level as a component of systems biology approaches and for identifying potential biomarkers of various disease states. The large amount of data generated by utilizing high efficiency (e.g., chromatographic) separations coupled to high mass accuracy mass spectrometry for high-throughput proteomics analyses presents challenges related to data processing, analysis, and display. This review focuses on recent advances in nanoLC-FTICR-MS-based proteomics approaches and the accompanying data processing tools that have been developed to display and interpret the large volumes of data being produced. PMID:16429408

  10. Tritium speciation in nuclear reactor bioshield concrete and its impact on accurate analysis.

    PubMed

    Kim, Dae Ji; E Warwick, Phillip; Croudace, Ian W

    2008-07-15

    Tritium ((3)H) is produced in nuclear reactors via several neutron-induced reactions [(2)H(n, gamma)(3)H, (6)Li(n, alpha)(3)H, (10)B(n, 2alpha)(3)H, (14)N(n, (3)H)(12)C, and ternary fission (fission yield <0.01%)]. Typically, (3)H is present as tritiated water (HTO) and can become adsorbed into structural concrete from the surface inward where it will be held in a weakly bound form. However, a systematic analysis of a sequence of subsamples taken from a reactor bioshield using combustion and liquid scintillation analysis has identified two forms of (3)H, one weakly bound and one strongly bound. The strongly bound tritium, which originates from neutron capture on trace lithium ((6)Li) within mineral phases, requires temperatures in excess of 350 degrees C to achieve quantitative recovery. The weakly bound form of tritium can be liberated at significantly lower temperatures (100 degrees C) as HTO and is associated with dehydration of hydrous mineral components. Without an appreciation that two forms of tritium can exist in reactor bioshields, the (3)H content of samples may be severely underestimated using conventional analytical approaches. These findings exemplify the need to develop robust radioactive waste characterization procedures in support of nuclear decommissioning programs.

  11. Toward a highly accurate ambulatory system for clinical gait analysis via UWB radios.

    PubMed

    Shaban, Heba A; Abou el-Nasr, Mohamad; Buehrer, R Michael

    2010-03-01

    In this paper, we propose and investigate a low-cost and low-complexity wireless ambulatory human locomotion tracking system that provides a high ranging accuracy (intersensor distance) suitable for the assessment of clinical gait analysis using wearable ultra wideband (UWB) transceivers. The system design and transceiver performance are presented in additive-white-gaussian noise and realistic channels, using industry accepted channel models for body area networks. The proposed system is theoretically capable of providing a ranging accuracy of 0.11 cm error at distances equivalent to interarker distances, at an 18 dB SNR in realistic on-body UWB channels. Based on real measurements, it provides the target ranging accuracy at an SNR = 20 dB. The achievable accuracy is ten times better than the accuracy reported in the literature for the intermarker-distance measurement. This makes it suitable for use in clinical gait analysis, and for the characterization and assessment of unstable mobility diseases, such as Parkinson's disease.

  12. Smartphone-Based Accurate Analysis of Retinal Vasculature towards Point-of-Care Diagnostics

    PubMed Central

    Xu, Xiayu; Ding, Wenxiang; Wang, Xuemin; Cao, Ruofan; Zhang, Maiye; Lv, Peilin; Xu, Feng

    2016-01-01

    Retinal vasculature analysis is important for the early diagnostics of various eye and systemic diseases, making it a potentially useful biomarker, especially for resource-limited regions and countries. Here we developed a smartphone-based retinal image analysis system for point-of-care diagnostics that is able to load a fundus image, segment retinal vessels, analyze individual vessel width, and store or uplink results. The proposed system was not only evaluated on widely used public databases and compared with the state-of-the-art methods, but also validated on clinical images directly acquired with a smartphone. An Android app is also developed to facilitate on-site application of the proposed methods. Both visual assessment and quantitative assessment showed that the proposed methods achieved comparable results to the state-of-the-art methods that require high-standard workstations. The proposed system holds great potential for the early diagnostics of various diseases, such as diabetic retinopathy, for resource-limited regions and countries. PMID:27698369

  13. Automated system for fast and accurate analysis of SF6 injected in the surface ocean.

    PubMed

    Koo, Chul-Min; Lee, Kitack; Kim, Miok; Kim, Dae-Ok

    2005-11-01

    This paper describes an automated sampling and analysis system for the shipboard measurement of dissolved sulfur hexafluoride (SF6) in surface marine environments into which SF6 has been deliberately released. This underway system includes a gas chromatograph associated with an electron capture detector, a fast and highly efficient SF6-extraction device, a global positioning system, and a data acquisition system based on Visual Basic 6.0/C 6.0. This work is distinct from previous studies in that it quantifies the efficiency of the SF6-extraction device and its carryover effect and examines the effect of surfactant on the SF6-extraction efficiency. Measurements can be continuously performed on seawater samples taken from a seawater line installed onboard a research vessel. The system runs on an hourly cycle during which one set of four SF6 standards is measured and SF6 derived from the seawater stream is subsequently analyzed for the rest of each 1 h period. This state-of-art system was successfully used to trace a water mass carrying Cochlodinium polykrikoides, which causes harmful algal blooms (HAB) in the coastal waters of southern Korea. The successful application of this analysis system in tracing the HAB-infected water mass suggests that the SF6 detection method described in this paper will improve the quality of the future study of biogeochemical processes in the marine environment.

  14. Accurate computations of the structures and binding energies of the imidazole⋯benzene and pyrrole⋯benzene complexes

    NASA Astrophysics Data System (ADS)

    Ahnen, Sandra; Hehn, Anna-Sophia; Vogiatzis, Konstantinos D.; Trachsel, Maria A.; Leutwyler, Samuel; Klopper, Wim

    2014-09-01

    Using explicitly-correlated coupled-cluster theory with single and double excitations, the intermolecular distances and interaction energies of the T-shaped imidazole⋯benzene and pyrrole⋯benzene complexes have been computed in a large augmented correlation-consistent quadruple-zeta basis set, adding also corrections for connected triple excitations and remaining basis-set-superposition errors. The results of these computations are used to assess other methods such as Møller-Plesset perturbation theory (MP2), spin-component-scaled MP2 theory, dispersion-weighted MP2 theory, interference-corrected explicitly-correlated MP2 theory, dispersion-corrected double-hybrid density-functional theory (DFT), DFT-based symmetry-adapted perturbation theory, the random-phase approximation, explicitly-correlated ring-coupled-cluster-doubles theory, and double-hybrid DFT with a correlation energy computed in the random-phase approximation.

  15. Accurate Ground-State Energies of Solids and Molecules from Time-Dependent Density-Functional Theory

    NASA Astrophysics Data System (ADS)

    Olsen, Thomas; Thygesen, Kristian S.

    2014-05-01

    We demonstrate that ground-state energies approaching chemical accuracy can be obtained by combining the adiabatic-connection fluctuation-dissipation theorem with time-dependent density-functional theory. The key ingredient is a renormalization scheme, which eliminates the divergence of the correlation hole characteristic of any local kernel. This new class of renormalized kernels gives a significantly better description of the short-range correlations in covalent bonds compared to the random phase approximation (RPA) and yields a fourfold improvement of RPA binding energies in both molecules and solids. We also consider examples of barrier heights in chemical reactions, molecular adsorption, and graphene interacting with metal surfaces, which are three examples where the RPA has been successful. In these cases, the renormalized kernel provides results that are of equal quality or even slightly better than the RPA, with a similar computational cost.

  16. Accurate Analytic Potential Energy Function and Spectroscopic Study for G1Πg State of Dimer 7Li2

    NASA Astrophysics Data System (ADS)

    Shi, De-Heng; Ma, Heng; Sun, Jin-Feng; Zhu, Zun-Lue

    2007-06-01

    The reasonable dissociation limit for the G1Πg state of dimer 7Li2 is determined. The equilibrium internuclear distance, dissociation energy, harmonic frequency, vibrational zero energy, and adiabatic excitation energy are calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space in Gaussian03 program package at such numerous basis sets as 6-311++G, 6-311++G(2df,2pd), 6-311++G(2df,p), cc-PVTZ, 6-311++G(3df,3pd), CEP-121G, 6-311++G(2df,pd), 6-311++G(d,p),6-311G(3df,3pd), D95(3df,3pd), 6-311++G(3df,2p), 6-311++G(2df), 6-311++G(df,pd) D95V++, and DGDZVP. The complete potential energy curves are obtained at these sets over a wide internuclear distance range and have least squares fitted to Murrell-Sorbie function. The conclusion shows that the basis set 6-311++G(2df,p) is a most suitable one for the G1Πg state. At this basis set, the calculated spectroscopic constants Te, De, E0, Re, ωe, ωeχe, αe, and Be are of 3.9523 eV, 0.813 06 eV, 113.56 cm-1, 0.320 15 nm, 227.96 cm-1, 1.6928 cm-1, 0.004 436 cm-1, and 0.4689 cm-1, respectively, which are in good agreement with measurements whenever available. The total 50 vibrational levels and corresponding inertial rotation constants are for the first time calculated and compared with available RKR data. And good agreement with measurements is obtained.

  17. A compact and accurate semi-global potential energy surface for malonaldehyde from constrained least squares regression

    SciTech Connect

    Mizukami, Wataru Tew, David P.; Habershon, Scott

    2014-10-14

    We present a new approach to semi-global potential energy surface fitting that uses the least absolute shrinkage and selection operator (LASSO) constrained least squares procedure to exploit an extremely flexible form for the potential function, while at the same time controlling the risk of overfitting and avoiding the introduction of unphysical features such as divergences or high-frequency oscillations. Drawing from a massively redundant set of overlapping distributed multi-dimensional Gaussian functions of inter-atomic separations we build a compact full-dimensional surface for malonaldehyde, fit to explicitly correlated coupled cluster CCSD(T)(F12*) energies with a root mean square deviations accuracy of 0.3%–0.5% up to 25 000 cm{sup −1} above equilibrium. Importance-sampled diffusion Monte Carlo calculations predict zero point energies for malonaldehyde and its deuterated isotopologue of 14 715.4(2) and 13 997.9(2) cm{sup −1} and hydrogen transfer tunnelling splittings of 21.0(4) and 3.2(4) cm{sup −1}, respectively, which are in excellent agreement with the experimental values of 21.583 and 2.915(4) cm{sup −1}.

  18. Third-Order Incremental Dual-Basis Set Zero-Buffer Approach: An Accurate and Efficient Way To Obtain CCSD and CCSD(T) Energies.

    PubMed

    Zhang, Jun; Dolg, Michael

    2013-07-09

    An efficient way to obtain accurate CCSD and CCSD(T) energies for large systems, i.e., the third-order incremental dual-basis set zero-buffer approach (inc3-db-B0), has been developed and tested. This approach combines the powerful incremental scheme with the dual-basis set method, and along with the new proposed K-means clustering (KM) method and zero-buffer (B0) approximation, can obtain very accurate absolute and relative energies efficiently. We tested the approach for 10 systems of different chemical nature, i.e., intermolecular interactions including hydrogen bonding, dispersion interaction, and halogen bonding; an intramolecular rearrangement reaction; aliphatic and conjugated hydrocarbon chains; three compact covalent molecules; and a water cluster. The results show that the errors for relative energies are <1.94 kJ/mol (or 0.46 kcal/mol), for absolute energies of <0.0026 hartree. By parallelization, our approach can be applied to molecules of more than 30 atoms and more than 100 correlated electrons with high-quality basis set such as cc-pVDZ or cc-pVTZ, saving computational cost by a factor of more than 10-20, compared to traditional implementation. The physical reasons of the success of the inc3-db-B0 approach are also analyzed.

  19. Comparing the standards of one metabolic equivalent of task in accurately estimating physical activity energy expenditure based on acceleration.

    PubMed

    Kim, Dohyun; Lee, Jongshill; Park, Hoon Ki; Jang, Dong Pyo; Song, Soohwa; Cho, Baek Hwan; Jung, Yoo-Suk; Park, Rae-Woong; Joo, Nam-Seok; Kim, In Young

    2016-08-24

    The purpose of the study is to analyse how the standard of resting metabolic rate (RMR) affects estimation of the metabolic equivalent of task (MET) using an accelerometer. In order to investigate the effect on estimation according to intensity of activity, comparisons were conducted between the 3.5 ml O2 · kg(-1) · min(-1) and individually measured resting VO2 as the standard of 1 MET. MET was estimated by linear regression equations that were derived through five-fold cross-validation using 2 types of MET values and accelerations; the accuracy of estimation was analysed through cross-validation, Bland and Altman plot, and one-way ANOVA test. There were no significant differences in the RMS error after cross-validation. However, the individual RMR-based estimations had as many as 0.5 METs of mean difference in modified Bland and Altman plots than RMR of 3.5 ml O2 · kg(-1) · min(-1). Finally, the results of an ANOVA test indicated that the individual RMR-based estimations had less significant differences between the reference and estimated values at each intensity of activity. In conclusion, the RMR standard is a factor that affects accurate estimation of METs by acceleration; therefore, RMR requires individual specification when it is used for estimation of METs using an accelerometer.

  20. An accurate and linear-scaling method for calculating charge-transfer excitation energies and diabatic couplings

    SciTech Connect

    Pavanello, Michele; Van Voorhis, Troy; Visscher, Lucas; Neugebauer, Johannes

    2013-02-07

    Quantum-mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those charge transfer excitations that take place between non-covalently bound molecules. In particular, we present a method that scales linearly with the number of non-covalently bound molecules in the system and is based on a two-pronged approach: The molecular electronic structure of broken-symmetry charge-localized states is obtained with the frozen density embedding formulation of subsystem density-functional theory; subsequently, in a post-SCF calculation, the full-electron Hamiltonian and overlap matrix elements among the charge-localized states are evaluated with an algorithm which takes full advantage of the subsystem DFT density partitioning technique. The method is benchmarked against coupled-cluster calculations and achieves chemical accuracy for the systems considered for intermolecular separations ranging from hydrogen-bond distances to tens of Angstroms. Numerical examples are provided for molecular clusters comprised of up to 56 non-covalently bound molecules.

  1. Combining multiple regression and principal component analysis for accurate predictions for column ozone in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim M.; MatJafri, M. Z.; Lim, H. S.

    2013-06-01

    This study encompasses columnar ozone modelling in the peninsular Malaysia. Data of eight atmospheric parameters [air surface temperature (AST), carbon monoxide (CO), methane (CH4), water vapour (H2Ovapour), skin surface temperature (SSKT), atmosphere temperature (AT), relative humidity (RH), and mean surface pressure (MSP)] data set, retrieved from NASA's Atmospheric Infrared Sounder (AIRS), for the entire period (2003-2008) was employed to develop models to predict the value of columnar ozone (O3) in study area. The combined method, which is based on using both multiple regressions combined with principal component analysis (PCA) modelling, was used to predict columnar ozone. This combined approach was utilized to improve the prediction accuracy of columnar ozone. Separate analysis was carried out for north east monsoon (NEM) and south west monsoon (SWM) seasons. The O3 was negatively correlated with CH4, H2Ovapour, RH, and MSP, whereas it was positively correlated with CO, AST, SSKT, and AT during both the NEM and SWM season periods. Multiple regression analysis was used to fit the columnar ozone data using the atmospheric parameter's variables as predictors. A variable selection method based on high loading of varimax rotated principal components was used to acquire subsets of the predictor variables to be comprised in the linear regression model of the atmospheric parameter's variables. It was found that the increase in columnar O3 value is associated with an increase in the values of AST, SSKT, AT, and CO and with a drop in the levels of CH4, H2Ovapour, RH, and MSP. The result of fitting the best models for the columnar O3 value using eight of the independent variables gave about the same values of the R (≈0.93) and R2 (≈0.86) for both the NEM and SWM seasons. The common variables that appeared in both regression equations were SSKT, CH4 and RH, and the principal precursor of the columnar O3 value in both the NEM and SWM seasons was SSKT.

  2. Duplicate portion sampling combined with spectrophotometric analysis affords the most accurate results when assessing daily dietary phosphorus intake.

    PubMed

    Navarro-Alarcon, Miguel; Zambrano, Esmeralda; Moreno-Montoro, Miriam; Agil, Ahmad; Olalla, Manuel

    2012-08-01

    The assessment of daily dietary phosphorus (P) intake is a major concern in human nutrition because of its relationship with Ca and Mg metabolism and osteoporosis. Within this context, we hypothesized that several of the methods available for the assessment of daily dietary intake of P are equally accurate and reliable, although few studies have been conducted to confirm this. The aim of this study then was to evaluate daily dietary P intake, which we did by 3 methods: duplicate portion sampling of 108 hospital meals, combined either with spectrophotometric analysis or the use of food composition tables, and 24-hour dietary recall for 3 consecutive days plus the use of food composition tables. The mean P daily dietary intakes found were 1106 ± 221, 1480 ± 221, and 1515 ± 223 mg/d, respectively. Daily dietary intake of P determined by spectrophotometric analysis was significantly lower (P < .001) and closer to dietary reference intakes for adolescents aged from 14 to 18 years (88.5%) and adult subjects (158.1%) compared with the other 2 methods. Duplicate portion sampling with P analysis takes into account the influence of technological and cooking processes on the P content of foods and meals and therefore afforded the most accurate and reliable P daily dietary intakes. The use of referred food composition tables overestimated daily dietary P intake. No adverse effects in relation to P nutrition (deficiencies or toxic effects) were encountered.

  3. Simulating Expert Clinical Comprehension: Adapting Latent Semantic Analysis to Accurately Extract Clinical Concepts from Psychiatric Narrative

    PubMed Central

    Cohen, Trevor; Blatter, Brett; Patel, Vimla

    2008-01-01

    Cognitive studies reveal that less-than-expert clinicians are less able to recognize meaningful patterns of data in clinical narratives. Accordingly, psychiatric residents early in training fail to attend to information that is relevant to diagnosis and the assessment of dangerousness. This manuscript presents cognitively motivated methodology for the simulation of expert ability to organize relevant findings supporting intermediate diagnostic hypotheses. Latent Semantic Analysis is used to generate a semantic space from which meaningful associations between psychiatric terms are derived. Diagnostically meaningful clusters are modeled as geometric structures within this space and compared to elements of psychiatric narrative text using semantic distance measures. A learning algorithm is defined that alters components of these geometric structures in response to labeled training data. Extraction and classification of relevant text segments is evaluated against expert annotation, with system-rater agreement approximating rater-rater agreement. A range of biomedical informatics applications for these methods are suggested. PMID:18455483

  4. Computer-implemented system and method for automated and highly accurate plaque analysis, reporting, and visualization

    NASA Technical Reports Server (NTRS)

    Kemp, James Herbert (Inventor); Talukder, Ashit (Inventor); Lambert, James (Inventor); Lam, Raymond (Inventor)

    2008-01-01

    A computer-implemented system and method of intra-oral analysis for measuring plaque removal is disclosed. The system includes hardware for real-time image acquisition and software to store the acquired images on a patient-by-patient basis. The system implements algorithms to segment teeth of interest from surrounding gum, and uses a real-time image-based morphing procedure to automatically overlay a grid onto each segmented tooth. Pattern recognition methods are used to classify plaque from surrounding gum and enamel, while ignoring glare effects due to the reflection of camera light and ambient light from enamel regions. The system integrates these components into a single software suite with an easy-to-use graphical user interface (GUI) that allows users to do an end-to-end run of a patient record, including tooth segmentation of all teeth, grid morphing of each segmented tooth, and plaque classification of each tooth image.

  5. An Accurate Method for Free Vibration Analysis of Structures with Application to Plates

    NASA Astrophysics Data System (ADS)

    KEVORKIAN, S.; PASCAL, M.

    2001-10-01

    In this work, the continuous element method which has been used as an alternative to the finite element method of vibration analysis of frames is applied to more general structures like 3-D continuum and rectangular plates. The method is based on the concept of the so-called impedance matrix giving in the frequency domain, the linear relation between the generalized displacements of the boundaries and the generalized forces exerted on these boundaries. For a 3-D continuum, the concept of impedance matrix is introduced assuming a particular kind of boundary conditions. For rectangular plates, this new development leads to the solution of vibration problems for boundary conditions other than the simply supported ones.

  6. Accurate wavelength calibration in the near-infrared for multielement analysis without the need for reference spectra

    SciTech Connect

    Asimellis, George; Giannoudakos, Aggelos; Kompitsas, Michael

    2006-12-10

    A new technique has been developed for an instant, precise, and accurate wavelength calibration over a wide pixel array for simultaneous, multielement spectral analysis based on an inverse numerical solution to the grating dispersion function.This technique is applicable to multielement analytical applications such as laser-induced breakdown spectroscopy (LIBS), particularly when using high-density gratings in the upper visible and in the near-infrared, where nonmetallic elements are detected.This application overcomes the need to use reference spectra for each window of observation and is tested on a commercially available LIBS instrument.

  7. Restriction Site Tiling Analysis: accurate discovery and quantitative genotyping of genome-wide polymorphisms using nucleotide arrays

    PubMed Central

    2010-01-01

    High-throughput genotype data can be used to identify genes important for local adaptation in wild populations, phenotypes in lab stocks, or disease-related traits in human medicine. Here we advance microarray-based genotyping for population genomics with Restriction Site Tiling Analysis. The approach simultaneously discovers polymorphisms and provides quantitative genotype data at 10,000s of loci. It is highly accurate and free from ascertainment bias. We apply the approach to uncover genomic differentiation in the purple sea urchin. PMID:20403197

  8. Accurate potential energy surface for the 1(2)A' state of NH(2): scaling of external correlation versus extrapolation to the complete basis set limit.

    PubMed

    Li, Y Q; Varandas, A J C

    2010-09-16

    An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system which is suitable for dynamics and kinetics studies of the reactions of N(2D) + H2(X1Sigmag+) NH(a1Delta) + H(2S) and their isotopomeric variants. It is obtained by fitting ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pVQZ basis set, after slightly correcting semiempirically the dynamical correlation using the double many-body expansion-scaled external correlation method. The function so obtained is compared in detail with a potential energy surface of the same family obtained by extrapolating the calculated raw energies to the complete basis set limit. The topographical features of the novel global potential energy surface are examined in detail and found to be in general good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. The novel function has been built so as to become degenerate at linear geometries with the ground-state potential energy surface of A'' symmetry reported by our group, where both form a Renner-Teller pair.

  9. Comparative Lifecycle Energy Analysis: Theory and Practice.

    ERIC Educational Resources Information Center

    Morris, Jeffrey; Canzoneri, Diana

    1992-01-01

    Explores the position that more energy is conserved through recycling secondary materials than is generated from municipal solid waste incineration. Discusses one component of a lifecycle analysis--a comparison of energy requirements for manufacturing competing products. Includes methodological issues, energy cost estimates, and difficulties…

  10. A Cost-Benefit and Accurate Method for Assessing Microalbuminuria: Single versus Frequent Urine Analysis.

    PubMed

    Hemmati, Roholla; Gharipour, Mojgan; Khosravi, Alireza; Jozan, Mahnaz

    2013-01-01

    Background. The purpose of this study was to answer the question whether a single testing for microalbuminuria results in a reliable conclusion leading costs saving. Methods. This current cross-sectional study included a total of 126 consecutive persons. Microalbuminuria was assessed by collection of two fasting random urine specimens on arrival to the clinic as well as one week later in the morning. Results. In overall, 17 out of 126 participants suffered from microalbuminuria that, among them, 12 subjects were also diagnosed as microalbuminuria once assessing this factor with a sensitivity of 70.6%, a specificity of 100%, a PPV of 100%, a NPV of 95.6%, and an accuracy of 96.0%. The measured sensitivity, specificity, PVV, NPV, and accuracy in hypertensive patients were 73.3%, 100%, 100%, 94.8%, and 95.5%, respectively. Also, these rates in nonhypertensive groups were 50.0%, 100%, 100%, 97.3%, and 97.4%, respectively. According to the ROC curve analysis, a single measurement of UACR had a high value for discriminating defected from normal renal function state (c = 0.989). Urinary albumin concentration in a single measurement had also high discriminative value for diagnosis of damaged kidney (c = 0.995). Conclusion. The single testing of both UACR and urine albumin level rather frequent testing leads to high diagnostic sensitivity, specificity, and accuracy as well as high predictive values in total population and also in hypertensive subgroups.

  11. Integrative subcellular proteomic analysis allows accurate prediction of human disease-causing genes

    PubMed Central

    Zhao, Li; Chen, Yiyun; Bajaj, Amol Onkar; Eblimit, Aiden; Xu, Mingchu; Soens, Zachry T.; Wang, Feng; Ge, Zhongqi; Jung, Sung Yun; He, Feng; Li, Yumei; Wensel, Theodore G.; Qin, Jun; Chen, Rui

    2016-01-01

    Proteomic profiling on subcellular fractions provides invaluable information regarding both protein abundance and subcellular localization. When integrated with other data sets, it can greatly enhance our ability to predict gene function genome-wide. In this study, we performed a comprehensive proteomic analysis on the light-sensing compartment of photoreceptors called the outer segment (OS). By comparing with the protein profile obtained from the retina tissue depleted of OS, an enrichment score for each protein is calculated to quantify protein subcellular localization, and 84% accuracy is achieved compared with experimental data. By integrating the protein OS enrichment score, the protein abundance, and the retina transcriptome, the probability of a gene playing an essential function in photoreceptor cells is derived with high specificity and sensitivity. As a result, a list of genes that will likely result in human retinal disease when mutated was identified and validated by previous literature and/or animal model studies. Therefore, this new methodology demonstrates the synergy of combining subcellular fractionation proteomics with other omics data sets and is generally applicable to other tissues and diseases. PMID:26912414

  12. Laser-Ablation Sampling for Accurate Analysis of Sulfur in Edible Salts.

    PubMed

    Lee, Yonghoon; Chirinos, Jose; Gonzalez, Jhanis; Oropeza, Dayana; Zorba, Vassilia; Mao, Xianglei; Yoo, Jonghyun; Russo, Richard E

    2017-04-01

    We evaluated the performance of laser ablation analysis techniques such as laser-induced breakdown spectroscopy (LIBS), laser ablation inductively coupled optical emission spectrometry (LA-ICP-OES), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), in comparison with that of ICP-OES using aqueous solutions for the quantification of sulfur (S) in edible salts from different geographical origins. We found that the laser ablation based sampling techniques were not influenced by loss of S, which was observed in ICP-OES with aqueous solutions for a certain salt upon their dissolution in aqueous solutions, originating from the formation of volatile species and precipitates upon their dilution in water. Although detection of S using direct laser sampling with LA-ICP-MS has well-known isobaric and polyatomic interferences, LIBS and LA-ICP-OES showed good accuracy in the detection of S for all salts. LIBS also provided the ability to identify the dominant chemical form in which S is present in salts. Correlation between S and oxygen, observed in LIBS spectra, provided chemical information about the presence of S(2-) or [Formula: see text], which are associated with the origin and quality of edible salts.

  13. Accurate analysis of taurine, anserine, carnosine and free amino acids in a cattle muscle biopsy sample.

    PubMed

    Imanari, Mai; Higuchi, Mikito; Shiba, Nobuya; Watanabe, Akira

    2010-06-01

    We have established an analysis method for some free amino acids (FAAs), as well as taurine (Tau), anserine (Ans) and carnosine (Car), in a fresh biopsy sample from cattle muscle. A series of model biopsy samples, corresponding to the mixtures of lean meat, fat and connective tissue, was prepared and showed high correlation coefficients between the compound concentration and the 3-methylhistidine (3-MeHis) content derived from hydrolysis of the biopsy sample (r = 0.74-0.95, P < 0.01). Interference from blood contamination could not be neglected, because the concentration of some FAAs in blood was comparable to that in muscle. However, it was possible to control the contamination of Tau, Ans, Car, glutamic acid, glutamine, asparatic acid and alanine to less than 5.0% when the blood contamination was controlled to less than 23%.These results suggest the necessity of measuring 3-MeHis as an index of lean meat and hemoglobin as an index of blood contamination when compounds in muscle biopsy samples are evaluated. We have carried out a series of these analyses using one biopsy sample and reveal differences in Tau, Ans, Car and some FAAs in beef muscle after different feeding regimes.

  14. Accurate determination of the diffusion coefficient of proteins by Fourier analysis with whole column imaging detection.

    PubMed

    Zarabadi, Atefeh S; Pawliszyn, Janusz

    2015-02-17

    Analysis in the frequency domain is considered a powerful tool to elicit precise information from spectroscopic signals. In this study, the Fourier transformation technique is employed to determine the diffusion coefficient (D) of a number of proteins in the frequency domain. Analytical approaches are investigated for determination of D from both experimental and data treatment viewpoints. The diffusion process is modeled to calculate diffusion coefficients based on the Fourier transformation solution to Fick's law equation, and its results are compared to time domain results. The simulations characterize optimum spatial and temporal conditions and demonstrate the noise tolerance of the method. The proposed model is validated by its application for the electropherograms from the diffusion path of a set of proteins. Real-time dynamic scanning is conducted to monitor dispersion by employing whole column imaging detection technology in combination with capillary isoelectric focusing (CIEF) and the imaging plug flow (iPF) experiment. These experimental techniques provide different peak shapes, which are utilized to demonstrate the Fourier transformation ability in extracting diffusion coefficients out of irregular shape signals. Experimental results confirmed that the Fourier transformation procedure substantially enhanced the accuracy of the determined values compared to those obtained in the time domain.

  15. Accurate modeling of antennas for radiating short pulses, FDTD analysis and experimental measurements

    NASA Astrophysics Data System (ADS)

    Maloney, James G.; Smith, Glenn S.

    1993-01-01

    Antennas used to radiate short pulses often require different design rules that those that are used to radiate essentially time-harmonic signals. The finite-difference time-domain (FDTD) method is a very flexible numerical approach that can be used to treat a variety of electromagnetic problems in the time domain. It is well suited to the analysis and design of antennas for radiating short pulses; however, several advances had to be made before the method could be applied to this problem. In this paper, we will illustrate the use of the FDTD method with two antennas designed for the radiation of short pulses. The first is a simple, two-dimensional geometry, and open-ended parallel-plate waveguide, while the second is a three-dimensional, rotationally symmetric geometry, a conical monopole fed through an image by a coaxial transmission line. Both antennas are 'optimized' according to given criteria by adjusting geometrical parameters and including resistive loading that varies continuously with position along the antenna. The predicted performance for the conical monopole antenna is compared with experimental measurements; this verifies the optimization and demonstrates the practicality of the design.

  16. Borehole flowmeter logging for the accurate design and analysis of tracer tests.

    PubMed

    Basiricò, Stefano; Crosta, Giovanni B; Frattini, Paolo; Villa, Alberto; Godio, Alberto

    2015-04-01

    Tracer tests often give ambiguous interpretations that may be due to the erroneous location of sampling points and/or the lack of flow rate measurements through the sampler. To obtain more reliable tracer test results, we propose a methodology that optimizes the design and analysis of tracer tests in a cross borehole mode by using vertical borehole flow rate measurements. Experiments using this approach, herein defined as the Bh-flow tracer test, have been performed by implementing three sequential steps: (1) single-hole flowmeter test, (2) cross-hole flowmeter test, and (3) tracer test. At the experimental site, core logging, pumping tests, and static water-level measurements were previously carried out to determine stratigraphy, fracture characteristics, and bulk hydraulic conductivity. Single-hole flowmeter testing makes it possible to detect the presence of vertical flows as well as inflow and outflow zones, whereas cross-hole flowmeter testing detects the presence of connections along sets of flow conduits or discontinuities intercepted by boreholes. Finally, the specific pathways and rates of groundwater flow through selected flowpaths are determined by tracer testing. We conclude that the combined use of single and cross-borehole flowmeter tests is fundamental to the formulation of the tracer test strategy and interpretation of the tracer test results.

  17. Energy Analysis Program 1990 annual report

    SciTech Connect

    Not Available

    1992-01-01

    The Energy Analysis Program has played an active role in the analysis and discussion of energy and environmental issues at several levels. (1) at the international level, with programs as developing scenarios for long-term energy demand in developing countries and organizing leading an analytic effort, ``Energy Efficiency, Developing Countries, and Eastern Europe,`` part of a major effort to increase support for energy efficiency programs worldwide; (2) at national level, the Program has been responsible for assessing energy forecasts and policies affecting energy use (e.g., appliance standards, National Energy Strategy scenarios); and (3) at the state and utility levels, the Program has been a leader in promoting integrated resource utility planning; the collaborative process has led to agreement on a new generation of utility demand-site programs in California, providing an opportunity to use knowledge and analytic techniques of the Program`s researchers. We continue to place highest on analyzing energy efficiency, with particular attention given to energy use in buildings. The Program continues its active analysis of international energy issues in Asia (including China), the Soviet Union, South America, and Western Europe. Analyzing the costs and benefits of different levels of standards for residential appliances continues to be the largest single area of research within the Program. The group has developed and applied techniques for forecasting energy demand (or constructing scenarios) for the United States. We have built a new model of industrial energy demand, are in the process of making major changes in our tools for forecasting residential energy demand, have built an extensive and documented energy conservation supply curve of residential energy use, and are beginning an analysis of energy-demand forecasting for commercial buildings.

  18. Energy Analysis Program 1990 annual report

    SciTech Connect

    Not Available

    1992-01-01

    The Energy Analysis Program has played an active role in the analysis and discussion of energy and environmental issues at several levels. (1) at the international level, with programs as developing scenarios for long-term energy demand in developing countries and organizing leading an analytic effort, Energy Efficiency, Developing Countries, and Eastern Europe,'' part of a major effort to increase support for energy efficiency programs worldwide; (2) at national level, the Program has been responsible for assessing energy forecasts and policies affecting energy use (e.g., appliance standards, National Energy Strategy scenarios); and (3) at the state and utility levels, the Program has been a leader in promoting integrated resource utility planning; the collaborative process has led to agreement on a new generation of utility demand-site programs in California, providing an opportunity to use knowledge and analytic techniques of the Program's researchers. We continue to place highest on analyzing energy efficiency, with particular attention given to energy use in buildings. The Program continues its active analysis of international energy issues in Asia (including China), the Soviet Union, South America, and Western Europe. Analyzing the costs and benefits of different levels of standards for residential appliances continues to be the largest single area of research within the Program. The group has developed and applied techniques for forecasting energy demand (or constructing scenarios) for the United States. We have built a new model of industrial energy demand, are in the process of making major changes in our tools for forecasting residential energy demand, have built an extensive and documented energy conservation supply curve of residential energy use, and are beginning an analysis of energy-demand forecasting for commercial buildings.

  19. The CHARMM-TURBOMOLE interface for efficient and accurate QM/MM molecular dynamics, free energies, and excited state properties.

    PubMed

    Riahi, Saleh; Rowley, Christopher N

    2014-10-30

    The quantum mechanical (QM)/molecular mechanical (MM) interface between Chemistry at HARvard Molecular Mechanics (CHARMM) and TURBOMOLE is described. CHARMM provides an extensive set of simulation algorithms, like molecular dynamics (MD) and free energy perturbation, and support for mature nonpolarizable and Drude polarizable force fields. TURBOMOLE provides fast QM calculations using density functional theory or wave function methods and excited state properties. CHARMM-TURBOMOLE is well-suited for extended QM/MM MD simulations using first principles methods with large (triple-ζ) basis sets. We demonstrate these capabilities with a QM/MM simulation of Mg(2+) (aq), where the MM outer sphere water molecules are represented using the SWM4-NDP Drude polarizable force field and the ion and inner coordination sphere are represented using QM PBE, PBE0, and MP2 methods. The relative solvation free energies of Mg(2+) and Zn(2+) were calculated using thermodynamic integration. We also demonstrate the features for excited state properties. We calculate the time-averaged solution absorption spectrum of indole, the emission spectrum of the indole 1La excited state, and the electronic circular dichroism spectrum of an oxacepham.

  20. Preoperative misdiagnosis analysis and accurate distinguish intrathymic cyst from small thymoma on computed tomography

    PubMed Central

    Li, Xin; Han, Xingpeng; Sun, Wei; Wang, Meng; Jing, Guohui

    2016-01-01

    Background To evaluate the role of computed tomography (CT) in preoperative diagnosis of intrathymic cyst and small thymoma, and determine the best CT threshold for distinguish intrathymic cyst from small thymoma. Methods We retrospectively reviewed the medical records of 30 patients (17 intrathymic cyst and 13 small thymoma) who had undergone mediastinal masses resection (with diameter less than 3 cm) under thoracoscope between January 2014 and July 2015 at our hospital. Clinical and CT features were compared and receiver-operating characteristics curve (ROC) analysis was performed. Results The CT value of small thymoma [39.5 HU (IQR, 33.7–42.2 HU)] was significantly higher than intrathymic cyst [25.8 HU (IQR, 22.3–29.3 HU), P=0.004]. When CT value was 31.2 HU, it could act as a threshold for identification of small thymoma and intrathymic cyst (the sensitivity and specificity was 92.3% and 82.4%, respectively). The ΔCT value of enhanced CT value with the non-enhanced CT value was significantly different between small thymoma [18.7 HU (IQR, 10.9–19.0 HU)] and intrathymic cyst [4.3 HU (IQR, 3.0–11.7 HU), P=0.04]. The density was more homogenous in intrathymic cyst than small thymoma, and the contour of the intrathymic cyst was more smoothly than small thymoma. Conclusions Preoperative CT scans could help clinicians to identify intrathymic cyst and small thymoma, and we recommend 31.2 HU as the best thresholds. Contrast-enhanced CT scans is useful for further identification of the two diseases. PMID:27621863

  1. Whole-Genome Sequencing Analysis Accurately Predicts Antimicrobial Resistance Phenotypes in Campylobacter spp.

    PubMed

    Zhao, S; Tyson, G H; Chen, Y; Li, C; Mukherjee, S; Young, S; Lam, C; Folster, J P; Whichard, J M; McDermott, P F

    2015-10-30

    The objectives of this study were to identify antimicrobial resistance genotypes for Campylobacter and to evaluate the correlation between resistance phenotypes and genotypes using in vitro antimicrobial susceptibility testing and whole-genome sequencing (WGS). A total of 114 Campylobacter species isolates (82 C. coli and 32 C. jejuni) obtained from 2000 to 2013 from humans, retail meats, and cecal samples from food production animals in the United States as part of the National Antimicrobial Resistance Monitoring System were selected for study. Resistance phenotypes were determined using broth microdilution of nine antimicrobials. Genomic DNA was sequenced using the Illumina MiSeq platform, and resistance genotypes were identified using assembled WGS sequences through blastx analysis. Eighteen resistance genes, including tet(O), blaOXA-61, catA, lnu(C), aph(2″)-Ib, aph(2″)-Ic, aph(2')-If, aph(2″)-Ig, aph(2″)-Ih, aac(6')-Ie-aph(2″)-Ia, aac(6')-Ie-aph(2″)-If, aac(6')-Im, aadE, sat4, ant(6'), aad9, aph(3')-Ic, and aph(3')-IIIa, and mutations in two housekeeping genes (gyrA and 23S rRNA) were identified. There was a high degree of correlation between phenotypic resistance to a given drug and the presence of one or more corresponding resistance genes. Phenotypic and genotypic correlation was 100% for tetracycline, ciprofloxacin/nalidixic acid, and erythromycin, and correlations ranged from 95.4% to 98.7% for gentamicin, azithromycin, clindamycin, and telithromycin. All isolates were susceptible to florfenicol, and no genes associated with florfenicol resistance were detected. There was a strong correlation (99.2%) between resistance genotypes and phenotypes, suggesting that WGS is a reliable indicator of resistance to the nine antimicrobial agents assayed in this study. WGS has the potential to be a powerful tool for antimicrobial resistance surveillance programs.

  2. Whole-Genome Sequencing Analysis Accurately Predicts Antimicrobial Resistance Phenotypes in Campylobacter spp.

    PubMed Central

    Tyson, G. H.; Chen, Y.; Li, C.; Mukherjee, S.; Young, S.; Lam, C.; Folster, J. P.; Whichard, J. M.; McDermott, P. F.

    2015-01-01

    The objectives of this study were to identify antimicrobial resistance genotypes for Campylobacter and to evaluate the correlation between resistance phenotypes and genotypes using in vitro antimicrobial susceptibility testing and whole-genome sequencing (WGS). A total of 114 Campylobacter species isolates (82 C. coli and 32 C. jejuni) obtained from 2000 to 2013 from humans, retail meats, and cecal samples from food production animals in the United States as part of the National Antimicrobial Resistance Monitoring System were selected for study. Resistance phenotypes were determined using broth microdilution of nine antimicrobials. Genomic DNA was sequenced using the Illumina MiSeq platform, and resistance genotypes were identified using assembled WGS sequences through blastx analysis. Eighteen resistance genes, including tet(O), blaOXA-61, catA, lnu(C), aph(2″)-Ib, aph(2″)-Ic, aph(2′)-If, aph(2″)-Ig, aph(2″)-Ih, aac(6′)-Ie-aph(2″)-Ia, aac(6′)-Ie-aph(2″)-If, aac(6′)-Im, aadE, sat4, ant(6′), aad9, aph(3′)-Ic, and aph(3′)-IIIa, and mutations in two housekeeping genes (gyrA and 23S rRNA) were identified. There was a high degree of correlation between phenotypic resistance to a given drug and the presence of one or more corresponding resistance genes. Phenotypic and genotypic correlation was 100% for tetracycline, ciprofloxacin/nalidixic acid, and erythromycin, and correlations ranged from 95.4% to 98.7% for gentamicin, azithromycin, clindamycin, and telithromycin. All isolates were susceptible to florfenicol, and no genes associated with florfenicol resistance were detected. There was a strong correlation (99.2%) between resistance genotypes and phenotypes, suggesting that WGS is a reliable indicator of resistance to the nine antimicrobial agents assayed in this study. WGS has the potential to be a powerful tool for antimicrobial resistance surveillance programs. PMID:26519386

  3. Exact vibrational energies of non-rotating H 2O and D 2O using an accurate ab initio potential

    NASA Astrophysics Data System (ADS)

    Bowman, Joel M.; Wierzbicki, Andrzej; Zúñiga, Jose

    1988-09-01

    Variationally exact vibrational energies are reported for non-rotating H 2O and D 2O using the recent CCSDT-1 ab initio potential of Bartlett, Cole, Purvis, Ermler, Hsieh and Shavitt as fit to an SPF quartic force field by Ermler. Twenty vibrational states are calculated for H 2O and D 2O and compared with experimental data. The agreement with experiment is fairly good; however, when the second-order bending force constant is reduced slightly, the agreement with experiment improves significantly. For eighteen states of H 2O the largest error is 15 cm -1 and the average absolute error is 6 cm -1. For eight states of D 2O the largest error is 7 cm -1 and the average absolute error is 4 cm -1.

  4. ArrayExplorer, a program in Visual Basic for robust and accurate filter cDNA array analysis.

    PubMed

    Patriotis, P C; Querec, T D; Gruver, B N; Brown, T R; Patriotis, C

    2001-10-01

    Determining the dynamics in the global regulation of gene expression holds the promise of bringing a better understanding of the processes that govern physiological cell growth regulation and its disruption during the development of disease. The advent for cDNA arrays has created the possibility for the parallel analysis of expression of thousands of genes in a given cell population, simultaneously. The level of expression of a given set of genes within the studied tissue corresponds to the intensity of a labeled cDNA probe synthesized from the studied tissue RNA and bound specifically to the cDNAs of the genes spotted on the array. The accurate extraction of gene expression intensity values is essential for further data analysis and the interpretation of the obtained results. Here, we describe a new array image-processing software developed in Microsoft Visual Basic, the ArrayExplorer, which provides a user-friendly, multiple-window interface and a number of automatic and manual features that facilitate a reliable, robust, and accurate extraction of gene intensity values from filter-array images.

  5. Barcoding T Cell Calcium Response Diversity with Methods for Automated and Accurate Analysis of Cell Signals (MAAACS)

    PubMed Central

    Sergé, Arnauld; Bernard, Anne-Marie; Phélipot, Marie-Claire; Bertaux, Nicolas; Fallet, Mathieu; Grenot, Pierre; Marguet, Didier; He, Hai-Tao; Hamon, Yannick

    2013-01-01

    We introduce a series of experimental procedures enabling sensitive calcium monitoring in T cell populations by confocal video-microscopy. Tracking and post-acquisition analysis was performed using Methods for Automated and Accurate Analysis of Cell Signals (MAAACS), a fully customized program that associates a high throughput tracking algorithm, an intuitive reconnection routine and a statistical platform to provide, at a glance, the calcium barcode of a population of individual T-cells. Combined with a sensitive calcium probe, this method allowed us to unravel the heterogeneity in shape and intensity of the calcium response in T cell populations and especially in naive T cells, which display intracellular calcium oscillations upon stimulation by antigen presenting cells. PMID:24086124

  6. Accurate potential energy functions, non-adiabatic and spin-orbit couplings in the ZnH(+) system.

    PubMed

    Liang, Guiying; Liu, Xiaoting; Zhang, Xiaomei; Xu, Haifeng; Yan, Bing

    2016-03-05

    A high-level ab initio calculation on the ZnH(+) cation has been carried out with the multi-reference configuration interaction method plus Davison correction (MRCI+Q). The scalar relativistic effect is included by using the Douglas-Kroll-Hess (DKH) method. The calculated potential energy curves (PECs) of the 7 Λ-S states are associated with the dissociation limits of Zn(+)((2)Sg)+H((2)Sg), Zn((1)Sg)+H(+)((1)Sg), and Zn(+)((2)Pu)+H((2)Sg), respectively (The Λ-S state is labeled as (2S+1)Λ, in which Λ is the quantum number for the projection along the internuclear axis of the total electronic orbital angular momentum and S is the total electron spin). The spectroscopic constants of the bound states are determined and in good agreement with the available theoretical and experimental results. The permanent dipole moments (PDMs) of Λ-S states and the spin-orbit (SO) matrix elements between Λ-S states are also computed. The results show that the abrupt changes of the PDMs and SO matrix elements come into being for the reason of the avoided crossing between the states with the same symmetry. In addition, the non-adiabatic couplings matrix elements between Λ-S states are also evaluated. Finally, the spin-orbit couplings (SOCs) for the low-lying states are considered with Breit-Pauli operator. The SOC effect makes the 7 Λ-S states of the ZnH(+) cation split into 12 Ω states (Ω=Λ+Sz, in which Sz is projection of the total electron spin S along the internuclear Z-axis). For the (3)0(+) state, the two energy minima exhibit in the potential, which could be attributed to the formation of the new avoided crossing point. The transition dipole moments (TDMs), Franck-Condon factors, and the radiative lifetimes of the selected transitions (2)0(+)-X0(+), (3)0(+)-X0(+), (2)1-X0(+) and (3)1-X0(+) have been reported.

  7. Accurate potential energy functions, non-adiabatic and spin-orbit couplings in the ZnH+ system

    NASA Astrophysics Data System (ADS)

    Liang, Guiying; Liu, Xiaoting; Zhang, Xiaomei; Xu, Haifeng; Yan, Bing

    2016-03-01

    A high-level ab initio calculation on the ZnH+ cation has been carried out with the multi-reference configuration interaction method plus Davison correction (MRCI + Q). The scalar relativistic effect is included by using the Douglas-Kroll-Hess (DKH) method. The calculated potential energy curves (PECs) of the 7 Λ-S states are associated with the dissociation limits of Zn+(2Sg) + H(2Sg), Zn(1Sg) + H+(1Sg), and Zn+(2Pu) + H(2Sg), respectively (The Λ-S state is labeled as 2S + 1Λ, in which Λ is the quantum number for the projection along the internuclear axis of the total electronic orbital angular momentum and S is the total electron spin). The spectroscopic constants of the bound states are determined and in good agreement with the available theoretical and experimental results. The permanent dipole moments (PDMs) of Λ-S states and the spin-orbit (SO) matrix elements between Λ-S states are also computed. The results show that the abrupt changes of the PDMs and SO matrix elements come into being for the reason of the avoided crossing between the states with the same symmetry. In addition, the non-adiabatic couplings matrix elements between Λ-S states are also evaluated. Finally, the spin-orbit couplings (SOCs) for the low-lying states are considered with Breit-Pauli operator. The SOC effect makes the 7 Λ-S states of the ZnH+ cation split into 12 Ω states (Ω = Λ + Sz, in which Sz is projection of the total electron spin S along the internuclear Z-axis). For the (3)0+ state, the two energy minima exhibit in the potential, which could be attributed to the formation of the new avoided crossing point. The transition dipole moments (TDMs), Franck-Condon factors, and the radiative lifetimes of the selected transitions (2)0+-X0+, (3)0+-X0+, (2)1-X0+ and (3)1-X0+ have been reported.

  8. NR2 and P3+: Accurate, Efficient Electron-Propagator Methods for Calculating Valence, Vertical Ionization Energies of Closed-Shell Molecules.

    PubMed

    Corzo, H H; Galano, Annia; Dolgounitcheva, O; Zakrzewski, V G; Ortiz, J V

    2015-08-20

    Two accurate and computationally efficient electron-propagator (EP) methods for calculating the valence, vertical ionization energies (VIEs) of closed-shell molecules have been identified through comparisons with related approximations. VIEs of a representative set of closed-shell molecules were calculated with EP methods using 10 basis sets. The most easily executed method, the diagonal, second-order (D2) EP approximation, produces results that steadily rise as basis sets are improved toward values based on extrapolated coupled-cluster singles and doubles plus perturbative triples calculations, but its mean errors remain unacceptably large. The outer valence Green function, partial third-order and renormalized partial third-order methods (P3+), which employ the diagonal self-energy approximation, produce markedly better results but have a greater tendency to overestimate VIEs with larger basis sets. The best combination of accuracy and efficiency with a diagonal self-energy matrix is the P3+ approximation, which exhibits the best trends with respect to basis-set saturation. Several renormalized methods with more flexible nondiagonal self-energies also have been examined: the two-particle, one-hole Tamm-Dancoff approximation (2ph-TDA), the third-order algebraic diagrammatic construction or ADC(3), the renormalized third-order (3+) method, and the nondiagonal second-order renormalized (NR2) approximation. Like D2, 2ph-TDA produces steady improvements with basis set augmentation, but its average errors are too large. Errors obtained with 3+ and ADC(3) are smaller on average than those of 2ph-TDA. These methods also have a greater tendency to overestimate VIEs with larger basis sets. The smallest average errors occur for the NR2 approximation; these errors decrease steadily with basis augmentations. As basis sets approach saturation, NR2 becomes the most accurate and efficient method with a nondiagonal self-energy.

  9. Accurate spectroscopic models for methane polyads derived from a potential energy surface using high-order contact transformations.

    PubMed

    Tyuterev, Vladimir; Tashkun, Sergei; Rey, Michael; Kochanov, Roman; Nikitin, Andrei; Delahaye, Thibault

    2013-12-19

    A new spectroscopic model is developed for theoretical predictions of vibration-rotation line positions and line intensities of the methane molecule. Resonance coupling parameters of the effective polyad Hamiltionians were obtained via high-order contact transformations (CT) from ab initio potential energy surface. This allows converging vibrational and rotational levels to the accuracy of best variational calculations. Average discrepancy with centers of 100 reliably assigned experimental bands up to the triacontad range was 0.74 cm(-1) and 0.001 cm(-1) for GS rotational levels up to J = 17 in direct CT calculations without adjustable parameters. A subsequent "fine tuning" of the diagonal parameters allows achieving experimental accuracy for about 5600 Dyad and Pentad line positions, whereas all resonance coupling parameters were held fixed to ab initio values. Dipole transition moment parameters were determined from selected ab initio line strengths previously computed from a dipole moment surface by variational method. New polyad model allows generating a spectral line list for the Dyad and Pentad bands with the accuracy ~10(-3) cm(-1) for line positions combined with ab initio predictions for line intensities. The overall integrated intensity agreement with Hitran-2008 empirical database is of 4.4% for the Dyad and of 1.8% for the Pentad range.

  10. Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for {sup 32}S{sup 16}O{sub 2} up to 8000 cm{sup −1}

    SciTech Connect

    Huang, Xinchuan E-mail: Timothy.J.Lee@nasa.gov; Schwenke, David W.; Lee, Timothy J. E-mail: Timothy.J.Lee@nasa.gov

    2014-03-21

    A purely ab initio potential energy surface (PES) was refined with selected {sup 32}S{sup 16}O{sub 2} HITRAN data. Compared to HITRAN, the root-mean-squares error (σ{sub RMS}) for all J = 0–80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm{sup −1}. Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296 K and covers up to 8000 cm{sup −1}. Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85%–90%. Our predictions for {sup 34}S{sup 16}O{sub 2} band origins, higher energy {sup 32}S{sup 16}O{sub 2} band origins and missing {sup 32}S{sup 16}O{sub 2} IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict {sup 32/34}S{sup 16}O{sub 2} band origins below 5500 cm{sup −1} with 0.01–0.03 cm{sup −1} uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The K{sub a}-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO{sub 2} IR spectral experimental analysis, as well as elimination of SO{sub 2} lines in high-resolution astronomical observations.

  11. An accurate full-dimensional potential energy surface for H–Au(111): Importance of nonadiabatic electronic excitation in energy transfer and adsorption

    SciTech Connect

    Janke, Svenja M.; Auerbach, Daniel J.; Kandratsenka, Alexander; Wodtke, Alec M.

    2015-09-28

    We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H–Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.

  12. An accurate full-dimensional potential energy surface for H-Au(111): Importance of nonadiabatic electronic excitation in energy transfer and adsorption.

    PubMed

    Janke, Svenja M; Auerbach, Daniel J; Wodtke, Alec M; Kandratsenka, Alexander

    2015-09-28

    We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H-Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.

  13. The readout of the LHC beam luminosity monitor: Accurate shower energy measurements at a 40 MHz repetition rate

    SciTech Connect

    Manfredi, P.F.; Ratti, L.; Speziali, V.; Traversi, G.; Manghisoni, M.; Re, V.; Denes, P.; Placidi, M.; Ratti, A.; Turner, W.C.; Datte, P.S.; Millaud, J.E.

    2003-05-10

    The LHC beam luminosity monitor is based on the following principle. The neutrals that originate in LHC at every PP interaction create showers in the absorbers placed in front of the cryogenic separation dipoles. The shower energy, as it can be measured by suitable detectors in the absorbers is proportional to the number of neutral particles and, therefore, to the luminosity. This principle lends itself to a luminosity measurement on a bunch-by-bunch basis. However, detector and front-end electronics must comply with extremely stringent requirements. To make the bunch-by-bunch measurement feasible, their speed of operation must match the 40 MHz bunch repetition rate of LHC. Besides, in the actual operation the detector must stand extremely high radiation doses. The front-end electronics, to survive, must be located at some distance from the region of high radiation field, which means that a properly terminated, low-noise, cable connection is needed between detector and front-end electronics. After briefly reviewing the solutions that have been adopted for the detector and the front-end electronics and the results that have been obtained so far in tests on the beam, the latest version of the instrument in describe in detail. It will be shown how a clever detector design, a suitable front-end conception based on the use of a ''cold resistance'' cable termination and a careful low-noise design, along with the use of an effective deconvolution algorithm, make the luminosity measurement possible on a bunch-by-bunch basis at the LHC bunch repetition rates.

  14. Analysis of Potential Energy Surfaces.

    ERIC Educational Resources Information Center

    Fernandez, G. M.; And Others

    1988-01-01

    Introduces different methodological strategies in analyzing potential energy surfaces (PES) used in chemical reactivity studies. Discusses the theory of PES and gives examples to be used for student work. Provides procedures for calculating normal coordinates and vibrational properties of an activated complex. (ML)

  15. Accurate double many-body expansion potential energy surface by extrapolation to the complete basis set limit and dynamics calculations for ground state of NH2.

    PubMed

    Li, Yongqing; Yuan, Jiuchuang; Chen, Maodu; Ma, Fengcai; Sun, Mengtao

    2013-07-15

    An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system. A switching function formalism has been used to warrant the correct behavior at the H2(X1Σg+)+N(2D) and NH (X3Σ-)+H(2S) dissociation channels involving nitrogen in the ground N(4S) and first excited N(2D) states. The topographical features of the novel global potential energy surface are examined in detail, and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. The novel surface can be using to treat well the Renner-Teller degeneracy of the 12A″ and 12A' states of NH 2. Such a work can both be recommended for dynamics studies of the N(2D)+H2 reaction and as building blocks for constructing the double many-body expansion potential energy surface of larger nitrogen/hydrogen-containing systems. In turn, a test theoretical study of the reaction N(2D)+H2(X1Σg+)(ν=0,j=0)→NH (X3Σ-)+H(2S) has been carried out with the method of quantum wave packet on the new potential energy surface. Reaction probabilities, integral cross sections, and differential cross sections have been calculated. Threshold exists because of the energy barrier (68.5 meV) along the minimum energy path. On the curve of reaction probability for total angular momentum J = 0, there are two sharp peaks just above threshold. The value of integral cross section increases quickly from zero to maximum with the increase of collision energy, and then stays stable with small oscillations. The differential cross section result shows that the reaction is a typical forward and backward scatter in agreement with experimental measurement result.

  16. Building America Top Innovations 2012: Building Energy Optimization Analysis Method (BEopt)

    SciTech Connect

    none,

    2013-01-01

    This Building America Top Innovations profile describes the DOE-sponsored BEopt software, which ensures a consistent analysis platform and accurate simulations. Many BEopt algorithms have been adopted by private-sector HERS software tools that have helped improve the energy efficiency of tens-of-thousands of ENERGY STAR-certified homes.

  17. Accurate prediction of higher-level electronic structure energies for large databases using neural networks, Hartree-Fock energies, and small subsets of the database.

    PubMed

    Malshe, M; Pukrittayakamee, A; Raff, L M; Hagan, M; Bukkapatnam, S; Komanduri, R

    2009-09-28

    A novel method is presented that significantly reduces the computational bottleneck of executing high-level, electronic structure calculations of the energies and their gradients for a large database that adequately samples the configuration space of importance for systems containing more than four atoms that are undergoing multiple, simultaneous reactions in several energetically open channels. The basis of the method is the high-degree of correlation that generally exists between the Hartree-Fock (HF) and higher-level electronic structure energies. It is shown that if the input vector to a neural network (NN) includes both the configuration coordinates and the HF energies of a small subset of the database, MP4(SDQ) energies with the same basis set can be predicted for the entire database using only the HF and MP4(SDQ) energies for the small subset and the HF energies for the remainder of the database. The predictive error is shown to be less than or equal to the NN fitting error if a NN is fitted to the entire database of higher-level electronic structure energies. The general method is applied to the computation of MP4(SDQ) energies of 68,308 configurations that comprise the database for the simultaneous, unimolecular decomposition of vinyl bromide into six different reaction channels. The predictive accuracy of the method is investigated by employing successively smaller subsets of the database to train the NN to predict the MP4(SDQ) energies of the remaining configurations of the database. The results indicate that for this system, the subset can be as small as 8% of the total number of configurations in the database without loss of accuracy beyond that expected if a NN is employed to fit the higher-level energies for the entire database. The utilization of this procedure is shown to save about 78% of the total computational time required for the execution of the MP4(SDQ) calculations. The sampling error involved with selection of the subset is shown to be

  18. Accurate prediction of higher-level electronic structure energies for large databases using neural networks, Hartree-Fock energies, and small subsets of the database

    NASA Astrophysics Data System (ADS)

    Malshe, M.; Pukrittayakamee, A.; Raff, L. M.; Hagan, M.; Bukkapatnam, S.; Komanduri, R.

    2009-09-01

    A novel method is presented that significantly reduces the computational bottleneck of executing high-level, electronic structure calculations of the energies and their gradients for a large database that adequately samples the configuration space of importance for systems containing more than four atoms that are undergoing multiple, simultaneous reactions in several energetically open channels. The basis of the method is the high-degree of correlation that generally exists between the Hartree-Fock (HF) and higher-level electronic structure energies. It is shown that if the input vector to a neural network (NN) includes both the configuration coordinates and the HF energies of a small subset of the database, MP4(SDQ) energies with the same basis set can be predicted for the entire database using only the HF and MP4(SDQ) energies for the small subset and the HF energies for the remainder of the database. The predictive error is shown to be less than or equal to the NN fitting error if a NN is fitted to the entire database of higher-level electronic structure energies. The general method is applied to the computation of MP4(SDQ) energies of 68 308 configurations that comprise the database for the simultaneous, unimolecular decomposition of vinyl bromide into six different reaction channels. The predictive accuracy of the method is investigated by employing successively smaller subsets of the database to train the NN to predict the MP4(SDQ) energies of the remaining configurations of the database. The results indicate that for this system, the subset can be as small as 8% of the total number of configurations in the database without loss of accuracy beyond that expected if a NN is employed to fit the higher-level energies for the entire database. The utilization of this procedure is shown to save about 78% of the total computational time required for the execution of the MP4(SDQ) calculations. The sampling error involved with selection of the subset is shown to be

  19. Accurate quantum wave packet calculations for the F + HCl → Cl + HF reaction on the ground 1(2)A' potential energy surface.

    PubMed

    Bulut, Niyazi; Kłos, Jacek; Alexander, Millard H

    2012-03-14

    We present converged exact quantum wave packet calculations of reaction probabilities, integral cross sections, and thermal rate coefficients for the title reaction. Calculations have been carried out on the ground 1(2)A' global adiabatic potential energy surface of Deskevich et al. [J. Chem. Phys. 124, 224303 (2006)]. Converged wave packet reaction probabilities at selected values of the total angular momentum up to a partial wave of J = 140 with the HCl reagent initially selected in the v = 0, j = 0-16 rovibrational states have been obtained for the collision energy range from threshold up to 0.8 eV. The present calculations confirm an important enhancement of reactivity with rotational excitation of the HCl molecule. First, accurate integral cross sections and rate constants have been calculated and compared with the available experimental data.

  20. Communication: An accurate full 15 dimensional permutationally invariant potential energy surface for the OH + CH4 → H2O + CH3 reaction

    NASA Astrophysics Data System (ADS)

    Li, Jun; Guo, Hua

    2015-12-01

    A globally accurate full-dimensional potential energy surface (PES) for the OH + CH4 → H2O + CH3 reaction is developed using the permutation invariant polynomial-neural network approach based on ˜135 000 points at the level of correlated coupled cluster singles, doubles, and perturbative triples level with the augmented correlation consistent polarized valence triple-zeta basis set. The total root mean square fitting error is only 3.9 meV or 0.09 kcal/mol. This PES is shown to reproduce energies, geometries, and harmonic frequencies of stationary points along the reaction path. Kinetic and dynamical calculations on the PES indicated a good agreement with the available experimental data.

  1. DCMB that combines divide-and-conquer and mixed-basis set methods for accurate geometry optimizations, total energies, and vibrational frequencies of large molecules.

    PubMed

    Wu, Anan; Xu, Xin

    2012-06-15

    We present a method, named DCMB, for the calculations of large molecules. It is a combination of a parallel divide-and-conquer (DC) method and a mixed-basis (MB) set scheme. In this approach, atomic forces, total energy and vibrational frequencies are obtained from a series of MB calculations, which are derived from the target system utilizing the DC concept. Unlike the fragmentation based methods, all DCMB calculations are performed over the whole target system and no artificial caps are introduced so that it is particularly useful for charged and/or delocalized systems. By comparing the DCMB results with those from the conventional method, we demonstrate that DCMB is capable of providing accurate prediction of molecular geometries, total energies, and vibrational frequencies of molecules of general interest. We also demonstrate that the high efficiency of the parallel DCMB code holds the promise for a routine geometry optimization of large complex systems.

  2. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide.

    PubMed

    Ross, Charles W; Simonsick, William J; Bogusky, Michael J; Celikay, Recep W; Guare, James P; Newton, Randall C

    2016-06-28

    Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

  3. An accurate retrieval of leaf water content from mid to thermal infrared spectra using continuous wavelet analysis.

    PubMed

    Ullah, Saleem; Skidmore, Andrew K; Naeem, Mohammad; Schlerf, Martin

    2012-10-15

    Leaf water content determines plant health, vitality, photosynthetic efficiency and is an important indicator of drought assessment. The retrieval of leaf water content from the visible to shortwave infrared spectra is well known. Here for the first time, we estimated leaf water content from the mid to thermal infrared (2.5-14.0 μm) spectra, based on continuous wavelet analysis. The dataset comprised 394 spectra from nine plant species, with different water contents achieved through progressive drying. To identify the spectral feature most sensitive to the variations in leaf water content, first the Directional Hemispherical Reflectance (DHR) spectra were transformed into a wavelet power scalogram, and then linear relations were established between the wavelet power scalogram and leaf water content. The six individual wavelet features identified in the mid infrared yielded high correlations with leaf water content (R(2)=0.86 maximum, 0.83 minimum), as well as low RMSE (minimum 8.56%, maximum 9.27%). The combination of four wavelet features produced the most accurate model (R(2)=0.88, RMSE=8.00%). The models were consistent in terms of accuracy estimation for both calibration and validation datasets, indicating that leaf water content can be accurately retrieved from the mid to thermal infrared domain of the electromagnetic radiation.

  4. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide

    PubMed Central

    Ross, Charles W.; Simonsick, William J.; Bogusky, Michael J.; Celikay, Recep W.; Guare, James P.; Newton, Randall C.

    2016-01-01

    Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry. PMID:27367671

  5. Energy disposal and thermal rate constants for the OH + HBr and OH + DBr reactions: quasiclassical trajectory calculations on an accurate potential energy surface.

    PubMed

    de Oliveira-Filho, Antonio G S; Ornellas, Fernando R; Bowman, Joel M

    2014-12-26

    We report reaction cross sections, energy disposal, and rate constants for the OH + HBr → Br + H2O and OH + DBr → Br + HDO reactions from quasiclassical trajectory calculations using an ab initio potential energy surface [ de Oliveira-Filho , A. G. S. ; Ornellas , F. R. ; Bowman , J. M. J. Phys. Chem. Lett. 2014 , 5 , 706 - 712 ]. Comparison with available experiments are made and generally show good agreement.

  6. Energy analysis program. 1995 Annual report

    SciTech Connect

    Levine, M.D.

    1996-05-01

    This year the role of energy technology research and analysis supporting governmental and public interests is again being challenged at high levels of government. This situation is not unlike that of the early 1980s, when the Administration questioned the relevance of a federal commitment to applied energy research, especially for energy efficiency and renewable energy technologies. Then Congress continued to support such activities, deeming them important to the nation`s interest. Today, Congress itself is challenging many facets of the federal role in energy. The Administration is also selectively reducing its support, primarily for the pragmatic objective of reducing federal expenditures, rather than because of principles opposing a public role in energy. this report is divided into three sections: International Energy and the global environment; Energy, economics, markets, and policy; and Buildings and their environment.

  7. A new method of accurate broken rotor bar diagnosis based on modulation signal bispectrum analysis of motor current signals

    NASA Astrophysics Data System (ADS)

    Gu, F.; Wang, T.; Alwodai, A.; Tian, X.; Shao, Y.; Ball, A. D.

    2015-01-01

    Motor current signature analysis (MCSA) has been an effective way of monitoring electrical machines for many years. However, inadequate accuracy in diagnosing incipient broken rotor bars (BRB) has motivated many studies into improving this method. In this paper a modulation signal bispectrum (MSB) analysis is applied to motor currents from different broken bar cases and a new MSB based sideband estimator (MSB-SE) and sideband amplitude estimator are introduced for obtaining the amplitude at (1 ± 2 s)fs (s is the rotor slip and fs is the fundamental supply frequency) with high accuracy. As the MSB-SE has a good performance of noise suppression, the new estimator produces more accurate results in predicting the number of BRB, compared with conventional power spectrum analysis. Moreover, the paper has also developed an improved model for motor current signals under rotor fault conditions and an effective method to decouple the BRB current which interferes with that of speed oscillations associated with BRB. These provide theoretical supports for the new estimators and clarify the issues in using conventional bispectrum analysis.

  8. Analysis of Energy-Absorbing Foundations.

    DTIC Science & Technology

    1978-12-15

    1ENN51YVAN&A 5TATL UNIV UNIVERSITY PARK DEPT OF ENGI-CYTC F/S 13/h ANALYSIS OF ENERGY -ABSORBING POUNDATIONS.(U) ECC 78 V H NEUBERT, S Ji YIN DNA01-78...C-0036 UNCLASSIFIED DNA-48OFP NL "M~ENOMOEE MIflfl END ______ 1 32 112.2 MICROCOPY RILSOLUTION TEST CHIART LELL ,NA 480 MIL ANALYSIS OF ENERGY ...8217 REPORT & PERIOD COVERED Final Report for Period ANALYSIS OF ENERGY -ABSORBING FOUNDATIONS I Dee 77-1S Dee 78 6. PERFORMING ORG, REPORT NUMBER 7AUTHOR

  9. A mechanical energy analysis of gait initiation

    NASA Technical Reports Server (NTRS)

    Miller, C. A.; Verstraete, M. C.

    1999-01-01

    The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

  10. Analysis and Optimization of Building Energy Consumption

    NASA Astrophysics Data System (ADS)

    Chuah, Jun Wei

    Energy is one of the most important resources required by modern human society. In 2010, energy expenditures represented 10% of global gross domestic product (GDP). By 2035, global energy consumption is expected to increase by more than 50% from current levels. The increased pace of global energy consumption leads to significant environmental and socioeconomic issues: (i) carbon emissions, from the burning of fossil fuels for energy, contribute to global warming, and (ii) increased energy expenditures lead to reduced standard of living. Efficient use of energy, through energy conservation measures, is an important step toward mitigating these effects. Residential and commercial buildings represent a prime target for energy conservation, comprising 21% of global energy consumption and 40% of the total energy consumption in the United States. This thesis describes techniques for the analysis and optimization of building energy consumption. The thesis focuses on building retrofits and building energy simulation as key areas in building energy optimization and analysis. The thesis first discusses and evaluates building-level renewable energy generation as a solution toward building energy optimization. The thesis next describes a novel heating system, called localized heating. Under localized heating, building occupants are heated individually by directed radiant heaters, resulting in a considerably reduced heated space and significant heating energy savings. To support localized heating, a minimally-intrusive indoor occupant positioning system is described. The thesis then discusses occupant-level sensing (OLS) as the next frontier in building energy optimization. OLS captures the exact environmental conditions faced by each building occupant, using sensors that are carried by all building occupants. The information provided by OLS enables fine-grained optimization for unprecedented levels of energy efficiency and occupant comfort. The thesis also describes a retrofit

  11. Accurate Enumeration of Aspergillus brasiliensis in Hair Color and Mascara by Time-Lapse Shadow Image Analysis.

    PubMed

    Ogawa, Hiroyuki; Matsuoka, Hideaki; Saito, Mikako

    2015-01-01

    The growth of black mold (Aspergillus brasiliensis) in black-colored samples such as hair color and mascara was measured with an automatic count system based on time-lapse shadow image analysis (TSIA). A. brasiliensis suspended in a lecithin and polysorbate (LP) solution of each sample (hair color or mascara) was spread on a potato dextrose agar medium plate containing LP. The background image darkness of the agar plate could be adjusted to attain accurate colony counts. 95 colonies in hair color and 22 colonies in mascara could be automatically determined at 48 h. The accuracy of the colony counts could be confirmed from the timelapse image data. In contrast, conventional visual counting at a specified time could not determine the number of colonies or led to false colony counts.

  12. Simple, fast, and accurate methodology for quantitative analysis using Fourier transform infrared spectroscopy, with bio-hybrid fuel cell examples.

    PubMed

    Mackie, David M; Jahnke, Justin P; Benyamin, Marcus S; Sumner, James J

    2016-01-01

    The standard methodologies for quantitative analysis (QA) of mixtures using Fourier transform infrared (FTIR) instruments have evolved until they are now more complicated than necessary for many users' purposes. We present a simpler methodology, suitable for widespread adoption of FTIR QA as a standard laboratory technique across disciplines by occasional users.•Algorithm is straightforward and intuitive, yet it is also fast, accurate, and robust.•Relies on component spectra, minimization of errors, and local adaptive mesh refinement.•Tested successfully on real mixtures of up to nine components. We show that our methodology is robust to challenging experimental conditions such as similar substances, component percentages differing by three orders of magnitude, and imperfect (noisy) spectra. As examples, we analyze biological, chemical, and physical aspects of bio-hybrid fuel cells.

  13. Quantitative polymerase chain reaction analysis of DNA from noninvasive samples for accurate microsatellite genotyping of wild chimpanzees (Pan troglodytes verus).

    PubMed

    Morin, P A; Chambers, K E; Boesch, C; Vigilant, L

    2001-07-01

    Noninvasive samples are useful for molecular genetic analyses of wild animal populations. However, the low DNA content of such samples makes DNA amplification difficult, and there is the potential for erroneous results when one of two alleles at heterozygous microsatellite loci fails to be amplified. In this study we describe an assay designed to measure the amount of amplifiable nuclear DNA in low DNA concentration extracts from noninvasive samples. We describe the range of DNA amounts obtained from chimpanzee faeces and shed hair samples and formulate a new efficient approach for accurate microsatellite genotyping. Prescreening of extracts for DNA quantity is recommended for sorting of samples for likely success and reliability. Repetition of results remains extensive for analysis of microsatellite amplifications beginning from low starting amounts of DNA, but is reduced for those with higher DNA content.

  14. Identification of Importin 8 (IPO8) as the most accurate reference gene for the clinicopathological analysis of lung specimens

    PubMed Central

    Nguewa, Paul A; Agorreta, Jackeline; Blanco, David; Lozano, Maria Dolores; Gomez-Roman, Javier; Sanchez, Blas A; Valles, Iñaki; Pajares, Maria J; Pio, Ruben; Rodriguez, Maria Jose; Montuenga, Luis M; Calvo, Alfonso

    2008-01-01

    Background The accurate normalization of differentially expressed genes in lung cancer is essential for the identification of novel therapeutic targets and biomarkers by real time RT-PCR and microarrays. Although classical "housekeeping" genes, such as GAPDH, HPRT1, and beta-actin have been widely used in the past, their accuracy as reference genes for lung tissues has not been proven. Results We have conducted a thorough analysis of a panel of 16 candidate reference genes for lung specimens and lung cell lines. Gene expression was measured by quantitative real time RT-PCR and expression stability was analyzed with the softwares GeNorm and NormFinder, mean of |ΔCt| (= |Ct Normal-Ct tumor|) ± SEM, and correlation coefficients among genes. Systematic comparison between candidates led us to the identification of a subset of suitable reference genes for clinical samples: IPO8, ACTB, POLR2A, 18S, and PPIA. Further analysis showed that IPO8 had a very low mean of |ΔCt| (0.70 ± 0.09), with no statistically significant differences between normal and malignant samples and with excellent expression stability. Conclusion Our data show that IPO8 is the most accurate reference gene for clinical lung specimens. In addition, we demonstrate that the commonly used genes GAPDH and HPRT1 are inappropriate to normalize data derived from lung biopsies, although they are suitable as reference genes for lung cell lines. We thus propose IPO8 as a novel reference gene for lung cancer samples. PMID:19014639

  15. A Global Approach to Accurate and Automatic Quantitative Analysis of NMR Spectra by Complex Least-Squares Curve Fitting

    NASA Astrophysics Data System (ADS)

    Martin, Y. L.

    The performance of quantitative analysis of 1D NMR spectra depends greatly on the choice of the NMR signal model. Complex least-squares analysis is well suited for optimizing the quantitative determination of spectra containing a limited number of signals (<30) obtained under satisfactory conditions of signal-to-noise ratio (>20). From a general point of view it is concluded, on the basis of mathematical considerations and numerical simulations, that, in the absence of truncation of the free-induction decay, complex least-squares curve fitting either in the time or in the frequency domain and linear-prediction methods are in fact nearly equivalent and give identical results. However, in the situation considered, complex least-squares analysis in the frequency domain is more flexible since it enables the quality of convergence to be appraised at every resonance position. An efficient data-processing strategy has been developed which makes use of an approximate conjugate-gradient algorithm. All spectral parameters (frequency, damping factors, amplitudes, phases, initial delay associated with intensity, and phase parameters of a baseline correction) are simultaneously managed in an integrated approach which is fully automatable. The behavior of the error as a function of the signal-to-noise ratio is theoretically estimated, and the influence of apodization is discussed. The least-squares curve fitting is theoretically proved to be the most accurate approach for quantitative analysis of 1D NMR data acquired with reasonable signal-to-noise ratio. The method enables complex spectral residuals to be sorted out. These residuals, which can be cumulated thanks to the possibility of correcting for frequency shifts and phase errors, extract systematic components, such as isotopic satellite lines, and characterize the shape and the intensity of the spectral distortion with respect to the Lorentzian model. This distortion is shown to be nearly independent of the chemical species

  16. On the determination of the crystal-vapor surface free energy, and why a Gaussian expression can be accurate for a system far from Gaussian

    NASA Astrophysics Data System (ADS)

    Modak, Viraj P.; Wyslouzil, Barbara E.; Singer, Sherwin J.

    2016-08-01

    The crystal-vapor surface free energy γ is an important physical parameter governing physical processes, such as wetting and adhesion. We explore exact and approximate routes to calculate γ based on cleaving an intact crystal into non-interacting sub-systems with crystal-vapor interfaces. We do this by turning off the interactions, ΔV, between the sub-systems. Using the soft-core scheme for turning off ΔV, we find that the free energy varies smoothly with the coupling parameter λ, and a single thermodynamic integration yields the exact γ. We generate another exact method, and a cumulant expansion for γ by expressing the surface free energy in terms of an average of e-βΔV in the intact crystal. The second cumulant, or Gaussian approximation for γ is surprisingly accurate in most situations, even though we find that the underlying probability distribution for ΔV is clearly not Gaussian. We account for this fact by developing a non-Gaussian theory for γ and find that the difference between the non-Gaussian and Gaussian expressions for γ consist of terms that are negligible in many situations. Exact and approximate methods are applied to the (111) surface of a Lennard-Jones crystal and are also tested for more complex molecular solids, the surface of octane and nonadecane. Alkane surfaces were chosen for study because their crystal-vapor surface free energy has been of particular interest for understanding surface freezing in these systems.

  17. On the determination of the crystal-vapor surface free energy, and why a Gaussian expression can be accurate for a system far from Gaussian.

    PubMed

    Modak, Viraj P; Wyslouzil, Barbara E; Singer, Sherwin J

    2016-08-07

    The crystal-vapor surface free energy γ is an important physical parameter governing physical processes, such as wetting and adhesion. We explore exact and approximate routes to calculate γ based on cleaving an intact crystal into non-interacting sub-systems with crystal-vapor interfaces. We do this by turning off the interactions, ΔV, between the sub-systems. Using the soft-core scheme for turning off ΔV, we find that the free energy varies smoothly with the coupling parameter λ, and a single thermodynamic integration yields the exact γ. We generate another exact method, and a cumulant expansion for γ by expressing the surface free energy in terms of an average of e(-βΔV) in the intact crystal. The second cumulant, or Gaussian approximation for γ is surprisingly accurate in most situations, even though we find that the underlying probability distribution for ΔV is clearly not Gaussian. We account for this fact by developing a non-Gaussian theory for γ and find that the difference between the non-Gaussian and Gaussian expressions for γ consist of terms that are negligible in many situations. Exact and approximate methods are applied to the (111) surface of a Lennard-Jones crystal and are also tested for more complex molecular solids, the surface of octane and nonadecane. Alkane surfaces were chosen for study because their crystal-vapor surface free energy has been of particular interest for understanding surface freezing in these systems.

  18. Advanced nuclear energy analysis technology.

    SciTech Connect

    Gauntt, Randall O.; Murata, Kenneth K.; Romero, Vicente JosÔe; Young, Michael Francis; Rochau, Gary Eugene

    2004-05-01

    A two-year effort focused on applying ASCI technology developed for the analysis of weapons systems to the state-of-the-art accident analysis of a nuclear reactor system was proposed. The Sandia SIERRA parallel computing platform for ASCI codes includes high-fidelity thermal, fluids, and structural codes whose coupling through SIERRA can be specifically tailored to the particular problem at hand to analyze complex multiphysics problems. Presently, however, the suite lacks several physics modules unique to the analysis of nuclear reactors. The NRC MELCOR code, not presently part of SIERRA, was developed to analyze severe accidents in present-technology reactor systems. We attempted to: (1) evaluate the SIERRA code suite for its current applicability to the analysis of next generation nuclear reactors, and the feasibility of implementing MELCOR models into the SIERRA suite, (2) examine the possibility of augmenting ASCI codes or alternatives by coupling to the MELCOR code, or portions thereof, to address physics particular to nuclear reactor issues, especially those facing next generation reactor designs, and (3) apply the coupled code set to a demonstration problem involving a nuclear reactor system. We were successful in completing the first two in sufficient detail to determine that an extensive demonstration problem was not feasible at this time. In the future, completion of this research would demonstrate the feasibility of performing high fidelity and rapid analyses of safety and design issues needed to support the development of next generation power reactor systems.

  19. Coupled dynamics analysis of wind energy systems

    NASA Technical Reports Server (NTRS)

    Hoffman, J. A.

    1977-01-01

    A qualitative description of all key elements of a complete wind energy system computer analysis code is presented. The analysis system addresses the coupled dynamics characteristics of wind energy systems, including the interactions of the rotor, tower, nacelle, power train, control system, and electrical network. The coupled dynamics are analyzed in both the frequency and time domain to provide the basic motions and loads data required for design, performance verification and operations analysis activities. Elements of the coupled analysis code were used to design and analyze candidate rotor articulation concepts. Fundamental results and conclusions derived from these studies are presented.

  20. MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO{sup +}(H{sub 2}O) cluster using accurate potential energy and dipole moment surfaces

    SciTech Connect

    Homayoon, Zahra

    2014-09-28

    A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO{sup +}(H{sub 2}O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO{sup +}(H{sub 2}O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water “antisymmetric” stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

  1. PEAR2.1. Residential Building Energy Analysis

    SciTech Connect

    Ritschard, R.L.

    1992-01-16

    PEAR (Program for Energy Analysis of Residences) provides an easy-to-use and accurate method of estimating the energy and cost savings associated with various energy conservation measures in site-built single-family homes. Measures such as ceiling, wall, and floor insulation; different window type and glazing layers; infiltration levels; and equipment efficiency can be considered. PEAR also allows the user to consider the effects of roof and wall color, movable night insulation on the windows, reflective and heat absorbing glass, an attached sunspace, and use of a night temperature setback. Regression techniques permit adjustments for different building geometries, window areas and orientations, wall construction, and extension of the data to 880 U.S. locations determined by climate parameters. Based on annual energy savings, user-specified costs of conservation measures, fuel, lifetime of measure, loan period, and fuel escalation and interest rates, PEAR calculates two economic indicators; the Simple Payback Period (SPP) and the Savings-to-Investment Ratio (SIR). Energy and cost savings of different sets of conservation measures can be compared in a single run. The program can be used both as a research tool by energy policy analysts and as a method for nontechnical energy calculation by architects, home builders, home owners, and others in the building industry.

  2. Built Environment Energy Analysis Tool Overview (Presentation)

    SciTech Connect

    Porter, C.

    2013-04-01

    This presentation provides an overview of the Built Environment Energy Analysis Tool, which is designed to assess impacts of future land use/built environment patterns on transportation-related energy use and greenhouse gas (GHG) emissions. The tool can be used to evaluate a range of population distribution and urban design scenarios for 2030 and 2050. This tool was produced as part of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  3. Accurate Analysis of the Change in Volume, Location, and Shape of Metastatic Cervical Lymph Nodes During Radiotherapy

    SciTech Connect

    Takao, Seishin; Tadano, Shigeru; Taguchi, Hiroshi; Yasuda, Koichi; Onimaru, Rikiya; Ishikawa, Masayori; Bengua, Gerard; Suzuki, Ryusuke; Shirato, Hiroki

    2011-11-01

    Purpose: To establish a method for the accurate acquisition and analysis of the variations in tumor volume, location, and three-dimensional (3D) shape of tumors during radiotherapy in the era of image-guided radiotherapy. Methods and Materials: Finite element models of lymph nodes were developed based on computed tomography (CT) images taken before the start of treatment and every week during the treatment period. A surface geometry map with a volumetric scale was adopted and used for the analysis. Six metastatic cervical lymph nodes, 3.5 to 55.1 cm{sup 3} before treatment, in 6 patients with head and neck carcinomas were analyzed in this study. Three fiducial markers implanted in mouthpieces were used for the fusion of CT images. Changes in the location of the lymph nodes were measured on the basis of these fiducial markers. Results: The surface geometry maps showed convex regions in red and concave regions in blue to ensure that the characteristics of the 3D tumor geometries are simply understood visually. After the irradiation of 66 to 70 Gy in 2 Gy daily doses, the patterns of the colors had not changed significantly, and the maps before and during treatment were strongly correlated (average correlation coefficient was 0.808), suggesting that the tumors shrank uniformly, maintaining the original characteristics of the shapes in all 6 patients. The movement of the gravitational center of the lymph nodes during the treatment period was everywhere less than {+-}5 mm except in 1 patient, in whom the change reached nearly 10 mm. Conclusions: The surface geometry map was useful for an accurate evaluation of the changes in volume and 3D shapes of metastatic lymph nodes. The fusion of the initial and follow-up CT images based on fiducial markers enabled an analysis of changes in the location of the targets. Metastatic cervical lymph nodes in patients were suggested to decrease in size without significant changes in the 3D shape during radiotherapy. The movements of the

  4. Is the Bethe–Salpeter Formalism Accurate for Excitation Energies? Comparisons with TD-DFT, CASPT2, and EOM-CCSD

    PubMed Central

    2017-01-01

    Developing ab initio approaches able to provide accurate excited-state energies at a reasonable computational cost is one of the biggest challenges in theoretical chemistry. In that framework, the Bethe–Salpeter equation approach, combined with the GW exchange-correlation self-energy, which maintains the same scaling with system size as TD-DFT, has recently been the focus of a rapidly increasing number of applications in molecular chemistry. Using a recently proposed set encompassing excitation energies of many kinds [J. Phys. Chem. Lett.2016, 7, 586–591], we investigate here the performances of BSE/GW. We compare these results to CASPT2, EOM-CCSD, and TD-DFT data and show that BSE/GW provides an accuracy comparable to the two wave function methods. It is particularly remarkable that the BSE/GW is equally efficient for valence, Rydberg, and charge-transfer excitations. In contrast, it provides a poor description of triplet excited states, for which EOM-CCSD and CASPT2 clearly outperform BSE/GW. This contribution therefore supports the use of the Bethe–Salpeter approach for spin-conserving transitions. PMID:28301726

  5. Is the Bethe-Salpeter Formalism Accurate for Excitation Energies ? Comparisons with TD-DFT, CASPT2 and EOM-CCSD.

    PubMed

    Jacquemin, Denis; Duchemin, Ivan; Blase, Xavier

    2017-03-16

    Developing ab initio approaches able to provide accurate excited-state energies at a reasonable computational cost is one of the biggest challenges in theoretical chemistry. In that framework the Bethe-Salpeter equation approach, combined with the GW exchange-correlation self-energy, that maintains the same scaling with system size as TD-DFT, has recently been the focus of a rapidly increasing number of applications in molecular chemistry. Using a recently-proposed set encompassing excitation energies of many kinds [J. Phys. Chem. Lett., 7 (2016), 586-591], we investigate here the performances of BSE/GW. We compare these results to CASPT2, EOM-CCSD, and TD-DFT data and show that BSE/GW provides an accuracy comparable to the two wavefunction methods. It is particularly remarkable that the BSE/GW is equally efficient for valence, Rydberg and charge-transfer excitations. In contrast, it provides a poor description of triplet excited-states, for which EOM-CCSD and CASPT2 clearly outperform BSE/GW. This contribution therefore supports the use of the Bethe-Salpeter approach for spin-conserving transitions.

  6. Explicitly correlated benchmark calculations on C8H8 isomer energy separations: how accurate are DFT, double-hybrid, and composite ab initio procedures?

    NASA Astrophysics Data System (ADS)

    Karton, Amir; Martin, Jan M. L.

    2012-10-01

    Accurate isomerization energies are obtained for a set of 45 C8H8 isomers by means of the high-level, ab initio W1-F12 thermochemical protocol. The 45 isomers involve a range of hydrocarbon functional groups, including (linear and cyclic) polyacetylene, polyyne, and cumulene moieties, as well as aromatic, anti-aromatic, and highly-strained rings. Performance of a variety of DFT functionals for the isomerization energies is evaluated. This proves to be a challenging test: only six of the 56 tested functionals attain root mean square deviations (RMSDs) below 3 kcal mol-1 (the performance of MP2), namely: 2.9 (B972-D), 2.8 (PW6B95), 2.7 (B3PW91-D), 2.2 (PWPB95-D3), 2.1 (ωB97X-D), and 1.2 (DSD-PBEP86) kcal mol-1. Isomers involving highly-strained fused rings or long cumulenic chains provide a 'torture test' for most functionals. Finally, we evaluate the performance of composite procedures (e.g. G4, G4(MP2), CBS-QB3, and CBS-APNO), as well as that of standard ab initio procedures (e.g. MP2, SCS-MP2, MP4, CCSD, and SCS-CCSD). Both connected triples and post-MP4 singles and doubles are important for accurate results. SCS-MP2 actually outperforms MP4(SDQ) for this problem, while SCS-MP3 yields similar performance as CCSD and slightly bests MP4. All the tested empirical composite procedures show excellent performance with RMSDs below 1 kcal mol-1.

  7. Energy Requirements of Adult Dogs: A Meta-Analysis

    PubMed Central

    Bermingham, Emma N.; Thomas, David G.; Cave, Nicholas J.; Morris, Penelope J.; Butterwick, Richard F.; German, Alexander J.

    2014-01-01

    A meta-analysis was conducted to determine the maintenance energy requirements of adult dogs. Suitable publications were first identified, and then used to generate relationships amongst energy requirements, husbandry, activity level, methodology, sex, neuter status, dog size, and age in healthy adult dogs. Allometric equations for maintenance energy requirements were determined using log-log linear regression. So that the resulting equations could readily be compared with equations reported by the National Research Council, maintenance energy requirements in the current study were determined in kcal/kg0.75 body weight (BW). Ultimately, the data of 70 treatment groups from 29 publications were used, and mean (± standard deviation) maintenance energy requirements were 142.8±55.3 kcal.kgBW−0.75.day−1. The corresponding allometric equation was 81.5 kcal.kgBW−0.93.day−1 (adjusted R2 = 0.64; 70 treatment groups). Type of husbandry had a significant effect on maintenance energy requirements (P<0.001): requirements were greatest in racing dogs, followed by working dogs and hunting dogs, whilst the energy requirements of pet dogs and kennel dogs were least. Maintenance energy requirements were less in neutered compared with sexually intact dogs (P<0.001), but there was no effect of sex. Further, reported activity level tended to effect the maintenance energy requirement of the dog (P = 0.09). This review suggests that estimating maintenance energy requirements based on BW alone may not be accurate, but that predictions that factor in husbandry, neuter status and, possibly, activity level might be superior. Additionally, more information on the nutrient requirements of older dogs, and those at the extremes of body size (i.e. giant and toy breeds) is needed. PMID:25313818

  8. An evaluation, comparison, and accurate benchmarking of several publicly available MS/MS search algorithms: Sensitivity and Specificity analysis.

    SciTech Connect

    Kapp, Eugene; Schutz, Frederick; Connolly, Lisa M.; Chakel, John A.; Meza, Jose E.; Miller, Christine A.; Fenyo, David; Eng, Jimmy K.; Adkins, Joshua N.; Omenn, Gilbert; Simpson, Richard

    2005-08-01

    MS/MS and associated database search algorithms are essential proteomic tools for identifying peptides. Due to their widespread use, it is now time to perform a systematic analysis of the various algorithms currently in use. Using blood specimens used in the HUPO Plasma Proteome Project, we have evaluated five search algorithms with respect to their sensitivity and specificity, and have also accurately benchmarked them based on specified false-positive (FP) rates. Spectrum Mill and SEQUEST performed well in terms of sensitivity, but were inferior to MASCOT, X-Tandem, and Sonar in terms of specificity. Overall, MASCOT, a probabilistic search algorithm, correctly identified most peptides based on a specified FP rate. The rescoring algorithm, Peptide Prophet, enhanced the overall performance of the SEQUEST algorithm, as well as provided predictable FP error rates. Ideally, score thresholds should be calculated for each peptide spectrum or minimally, derived from a reversed-sequence search as demonstrated in this study based on a validated data set. The availability of open-source search algorithms, such as X-Tandem, makes it feasible to further improve the validation process (manual or automatic) on the basis of ''consensus scoring'', i.e., the use of multiple (at least two) search algorithms to reduce the number of FPs. complement.

  9. A Feasibility Study for Measuring Accurate Chest Compression Depth and Rate on Soft Surfaces Using Two Accelerometers and Spectral Analysis.

    PubMed

    Ruiz de Gauna, Sofía; González-Otero, Digna M; Ruiz, Jesus; Gutiérrez, J J; Russell, James K

    2016-01-01

    Background. Cardiopulmonary resuscitation (CPR) feedback devices are being increasingly used. However, current accelerometer-based devices overestimate chest displacement when CPR is performed on soft surfaces, which may lead to insufficient compression depth. Aim. To assess the performance of a new algorithm for measuring compression depth and rate based on two accelerometers in a simulated resuscitation scenario. Materials and Methods. Compressions were provided to a manikin on two mattresses, foam and sprung, with and without a backboard. One accelerometer was placed on the chest and the second at the manikin's back. Chest displacement and mattress displacement were calculated from the spectral analysis of the corresponding acceleration every 2 seconds and subtracted to compute the actual sternal-spinal displacement. Compression rate was obtained from the chest acceleration. Results. Median unsigned error in depth was 2.1 mm (4.4%). Error was 2.4 mm in the foam and 1.7 mm in the sprung mattress (p < 0.001). Error was 3.1/2.0 mm and 1.8/1.6 mm with/without backboard for foam and sprung, respectively (p < 0.001). Median error in rate was 0.9 cpm (1.0%), with no significant differences between test conditions. Conclusion. The system provided accurate feedback on chest compression depth and rate on soft surfaces. Our solution compensated mattress displacement, avoiding overestimation of compression depth when CPR is performed on soft surfaces.

  10. Analysis and accurate reconstruction of incomplete data in X-ray differential phase-contrast computed tomography.

    PubMed

    Fu, Jian; Tan, Renbo; Chen, Liyuan

    2014-01-01

    X-ray differential phase-contrast computed tomography (DPC-CT) is a powerful physical and biochemical analysis tool. In practical applications, there are often challenges for DPC-CT due to insufficient data caused by few-view, bad or missing detector channels, or limited scanning angular range. They occur quite frequently because of experimental constraints from imaging hardware, scanning geometry, and the exposure dose delivered to living specimens. In this work, we analyze the influence of incomplete data on DPC-CT image reconstruction. Then, a reconstruction method is developed and investigated for incomplete data DPC-CT. It is based on an algebraic iteration reconstruction technique, which minimizes the image total variation and permits accurate tomographic imaging with less data. This work comprises a numerical study of the method and its experimental verification using a dataset measured at the W2 beamline of the storage ring DORIS III equipped with a Talbot-Lau interferometer. The numerical and experimental results demonstrate that the presented method can handle incomplete data. It will be of interest for a wide range of DPC-CT applications in medicine, biology, and nondestructive testing.

  11. A Feasibility Study for Measuring Accurate Chest Compression Depth and Rate on Soft Surfaces Using Two Accelerometers and Spectral Analysis

    PubMed Central

    Gutiérrez, J. J.; Russell, James K.

    2016-01-01

    Background. Cardiopulmonary resuscitation (CPR) feedback devices are being increasingly used. However, current accelerometer-based devices overestimate chest displacement when CPR is performed on soft surfaces, which may lead to insufficient compression depth. Aim. To assess the performance of a new algorithm for measuring compression depth and rate based on two accelerometers in a simulated resuscitation scenario. Materials and Methods. Compressions were provided to a manikin on two mattresses, foam and sprung, with and without a backboard. One accelerometer was placed on the chest and the second at the manikin's back. Chest displacement and mattress displacement were calculated from the spectral analysis of the corresponding acceleration every 2 seconds and subtracted to compute the actual sternal-spinal displacement. Compression rate was obtained from the chest acceleration. Results. Median unsigned error in depth was 2.1 mm (4.4%). Error was 2.4 mm in the foam and 1.7 mm in the sprung mattress (p < 0.001). Error was 3.1/2.0 mm and 1.8/1.6 mm with/without backboard for foam and sprung, respectively (p < 0.001). Median error in rate was 0.9 cpm (1.0%), with no significant differences between test conditions. Conclusion. The system provided accurate feedback on chest compression depth and rate on soft surfaces. Our solution compensated mattress displacement, avoiding overestimation of compression depth when CPR is performed on soft surfaces. PMID:27999808

  12. Mathematical analysis and algorithms for efficiently and accurately implementing stochastic simulations of short-term synaptic depression and facilitation.

    PubMed

    McDonnell, Mark D; Mohan, Ashutosh; Stricker, Christian

    2013-01-01

    The release of neurotransmitter vesicles after arrival of a pre-synaptic action potential (AP) at cortical synapses is known to be a stochastic process, as is the availability of vesicles for release. These processes are known to also depend on the recent history of AP arrivals, and this can be described in terms of time-varying probabilities of vesicle release. Mathematical models of such synaptic dynamics frequently are based only on the mean number of vesicles released by each pre-synaptic AP, since if it is assumed there are sufficiently many vesicle sites, then variance is small. However, it has been shown recently that variance across sites can be significant for neuron and network dynamics, and this suggests the potential importance of studying short-term plasticity using simulations that do generate trial-to-trial variability. Therefore, in this paper we study several well-known conceptual models for stochastic availability and release. We state explicitly the random variables that these models describe and propose efficient algorithms for accurately implementing stochastic simulations of these random variables in software or hardware. Our results are complemented by mathematical analysis and statement of pseudo-code algorithms.

  13. Development and experimental verification of a finite element method for accurate analysis of a surface acoustic wave device

    NASA Astrophysics Data System (ADS)

    Mohibul Kabir, K. M.; Matthews, Glenn I.; Sabri, Ylias M.; Russo, Salvy P.; Ippolito, Samuel J.; Bhargava, Suresh K.

    2016-03-01

    Accurate analysis of surface acoustic wave (SAW) devices is highly important due to their use in ever-growing applications in electronics, telecommunication and chemical sensing. In this study, a novel approach for analyzing the SAW devices was developed based on a series of two-dimensional finite element method (FEM) simulations, which has been experimentally verified. It was found that the frequency response of the two SAW device structures, each having slightly different bandwidth and center lobe characteristics, can be successfully obtained utilizing the current density of the electrodes via FEM simulations. The two SAW structures were based on XY Lithium Niobate (LiNbO3) substrates and had two and four electrode finger pairs in both of their interdigital transducers, respectively. Later, SAW devices were fabricated in accordance with the simulated models and their measured frequency responses were found to correlate well with the obtained simulations results. The results indicated that better match between calculated and measured frequency response can be obtained when one of the input electrode finger pairs was set at zero volts and all the current density components were taken into account when calculating the frequency response of the simulated SAW device structures.

  14. Accurate mass fragment library for rapid analysis of pesticides on produce using ambient pressure desorption ionization with high-resolution mass spectrometry.

    PubMed

    Kern, Sara E; Lin, Lora A; Fricke, Frederick L

    2014-08-01

    U.S. food imports have been increasing steadily for decades, intensifying the need for a rapid and sensitive screening technique. A method has been developed that uses foam disks to sample the surface of incoming produce. This work provides complimentary information to the extensive amount of published pesticide fragmentation data collected using LCMS systems (Sack et al. Journal of Agricultural and Food Chemistry, 59, 6383-6411, 2011; Mol et al. Analytical and Bioanalytical Chemistry, 403, 2891-2908, 2012). The disks are directly analyzed using transmission-mode direct analysis in real time (DART) ambient pressure desorption ionization coupled to a high resolution accurate mass-mass spectrometer (HRAM-MS). In order to provide more certainty in the identification of the pesticides detected, a library of accurate mass fragments and isotopes of the protonated parent molecular ion (the [M+H]⁺) has been developed. The HRAM-MS is equipped with a quadrupole mass filter, providing the capability of "data-dependent" fragmentation, as opposed to "all -ion" fragmentation (where all of the ions enter a collision chamber and are fragmented at once). A temperature gradient for the DART helium stream and multiple collision energies were employed to detect and fragment 164 pesticides of varying chemical classes, sizes, and polarities. The accurate mass information of precursor ([M+H]⁺ ion) and fragment ions is essential in correctly identifying chemical contaminants on the surface of imported produce. Additionally, the inclusion of isotopes of the [M+H]⁺ in the database adds another metric to the confirmation process. The fragmentation data were collected using a Q-Exactive mass spectrometer and were added to a database used to process data collected with an Exactive mass spectrometer, an instrument that is more readily available for this screening application. The commodities investigated range from smooth-skinned produce such as apples to rougher surfaces like broccoli

  15. Accurate Mass Fragment Library for Rapid Analysis of Pesticides on Produce Using Ambient Pressure Desorption Ionization with High-Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Kern, Sara E.; Lin, Lora A.; Fricke, Frederick L.

    2014-08-01

    U.S. food imports have been increasing steadily for decades, intensifying the need for a rapid and sensitive screening technique. A method has been developed that uses foam disks to sample the surface of incoming produce. This work provides complimentary information to the extensive amount of published pesticide fragmentation data collected using LCMS systems (Sack et al. Journal of Agricultural and Food Chemistry, 59, 6383-6411, 2011; Mol et al. Analytical and Bioanalytical Chemistry, 403, 2891-2908, 2012). The disks are directly analyzed using transmission-mode direct analysis in real time (DART) ambient pressure desorption ionization coupled to a high resolution accurate mass-mass spectrometer (HRAM-MS). In order to provide more certainty in the identification of the pesticides detected, a library of accurate mass fragments and isotopes of the protonated parent molecular ion (the [M+H]+) has been developed. The HRAM-MS is equipped with a quadrupole mass filter, providing the capability of "data-dependent" fragmentation, as opposed to "all -ion" fragmentation (where all of the ions enter a collision chamber and are fragmented at once). A temperature gradient for the DART helium stream and multiple collision energies were employed to detect and fragment 164 pesticides of varying chemical classes, sizes, and polarities. The accurate mass information of precursor ([M+H]+ ion) and fragment ions is essential in correctly identifying chemical contaminants on the surface of imported produce. Additionally, the inclusion of isotopes of the [M+H]+ in the database adds another metric to the confirmation process. The fragmentation data were collected using a Q-Exactive mass spectrometer and were added to a database used to process data collected with an Exactive mass spectrometer, an instrument that is more readily available for this screening application. The commodities investigated range from smooth-skinned produce such as apples to rougher surfaces like broccoli. The

  16. Precise and Accurate Trace Element Analysis of Calcium Carbonate by LA-ICP-MS and its Application to Stalagmites

    NASA Astrophysics Data System (ADS)

    Jochum, K. P.; Scholz, D.; Stoll, B.; Weis, U.; Yang, Q.; Andreae, M. O.

    2011-12-01

    , therefore, not be used for accurate micro-analysis at low mass resolution. As shown by many publications, non-matrix matched calibration and the so-called mass load effect may result in incorrect LA-ICP-MS data. Our investigations with different matrix materials show that the relative sensitivity factors (RSF) of most elements are within ~10%. However, the RSF of carbonate and geological samples differ by up to 40% from those of the NIST silicate glasses for the chalcophile elements Cu, Zn, Ge, Mo, Cd, Sn, Tl, Pb. We have tested a new procedure for analysis of calcite and aragonite phases of a stalagmite from the Hüttenbläserschachthöhle, Germany, by using low and medium mass resolution and appropriate RSF. Because of higher count rates, the detection limits of interference-free isotopes are much lower for low mass resolution than for medium mass resolution. For interfered mass lines the detection limits are, however, lower for medium mass resolution. For example, the detection limit for 24Mg is 0.2 μg/g for medium mass resolution compared to 500 μg/g for low mass resolution. Thus, it is possible to accurately measure the three Mg isotopes for Mg concentrations down to several μg/g.

  17. Magnetic properties and energy-mapping analysis.

    PubMed

    Xiang, Hongjun; Lee, Changhoon; Koo, Hyun-Joo; Gong, Xingao; Whangbo, Myung-Hwan

    2013-01-28

    The magnetic energy levels of a given magnetic solid are closely packed in energy because the interactions between magnetic ions are weak. Thus, in describing its magnetic properties, one needs to generate its magnetic energy spectrum by employing an appropriate spin Hamiltonian. In this review article we discuss how to determine and specify a necessary spin Hamiltonian in terms of first principles electronic structure calculations on the basis of energy-mapping analysis and briefly survey important concepts and phenomena that one encounters in reading the current literature on magnetic solids. Our discussion is given on a qualitative level from the perspective of magnetic energy levels and electronic structures. The spin Hamiltonian appropriate for a magnetic system should be based on its spin lattice, i.e., the repeat pattern of its strong magnetic bonds (strong spin exchange paths), which requires one to evaluate its Heisenberg spin exchanges on the basis of energy-mapping analysis. Other weaker energy terms such as Dzyaloshinskii-Moriya (DM) spin exchange and magnetocrystalline anisotropy energies, which a spin Hamiltonian must include in certain cases, can also be evaluated by performing energy-mapping analysis. We show that the spin orientation of a transition-metal magnetic ion can be easily explained by considering its split d-block levels as unperturbed states with the spin-orbit coupling (SOC) as perturbation, that the DM exchange between adjacent spin sites can become comparable in strength to the Heisenberg spin exchange when the two spin sites are not chemically equivalent, and that the DM interaction between rare-earth and transition-metal cations is governed largely by the magnetic orbitals of the rare-earth cation.

  18. Small and efficient basis sets for the evaluation of accurate interaction energies: aromatic molecule-argon ground-state intermolecular potentials and rovibrational states.

    PubMed

    Cybulski, Hubert; Baranowska-Łączkowska, Angelika; Henriksen, Christian; Fernández, Berta

    2014-11-06

    By evaluating a representative set of CCSD(T) ground state interaction energies for van der Waals dimers formed by aromatic molecules and the argon atom, we test the performance of the polarized basis sets of Sadlej et al. (J. Comput. Chem. 2005, 26, 145; Collect. Czech. Chem. Commun. 1988, 53, 1995) and the augmented polarization-consistent bases of Jensen (J. Chem. Phys. 2002, 117, 9234) in providing accurate intermolecular potentials for the benzene-, naphthalene-, and anthracene-argon complexes. The basis sets are extended by addition of midbond functions. As reference we consider CCSD(T) results obtained with Dunning's bases. For the benzene complex a systematic basis set study resulted in the selection of the (Z)Pol-33211 and the aug-pc-1-33321 bases to obtain the intermolecular potential energy surface. The interaction energy values and the shape of the CCSD(T)/(Z)Pol-33211 calculated potential are very close to the best available CCSD(T)/aug-cc-pVTZ-33211 potential with the former basis set being considerably smaller. The corresponding differences for the CCSD(T)/aug-pc-1-33321 potential are larger. In the case of the naphthalene-argon complex, following a similar study, we selected the (Z)Pol-3322 and aug-pc-1-333221 bases. The potentials show four symmetric absolute minima with energies of -483.2 cm(-1) for the (Z)Pol-3322 and -486.7 cm(-1) for the aug-pc-1-333221 basis set. To further check the performance of the selected basis sets, we evaluate intermolecular bound states of the complexes. The differences between calculated vibrational levels using the CCSD(T)/(Z)Pol-33211 and CCSD(T)/aug-cc-pVTZ-33211 benzene-argon potentials are small and for the lowest energy levels do not exceed 0.70 cm(-1). Such differences are substantially larger for the CCSD(T)/aug-pc-1-33321 calculated potential. For naphthalene-argon, bound state calculations demonstrate that the (Z)Pol-3322 and aug-pc-1-333221 potentials are of similar quality. The results show that these

  19. Accurate double many-body expansion potential energy surface for N3((4)A'') from correlation scaled ab initio energies with extrapolation to the complete basis set limit.

    PubMed

    Galvão, B R L; Varandas, A J C

    2009-12-31

    A new global potential energy surface is reported for the (4)A'' ground electronic state of the N(3) system from double many-body expansion theory and an extensive set of accurate ab initio energies extrapolated to the complete basis set limit. It shows three equivalent metastable potential wells for C(2v) geometries that are separated from the three N((4)S) + N(2) asymptotes by energy barriers as predicted from previous ab initio work. The potential well and barrier height now predicted lie 42.9 and 45.9 kcal mol(-1) above the atom-diatom dissociation limit, respectively, being about 1 kcal mol(-1) lower than previous theoretical estimates. The ab initio calculations here reported predict also a (4)B(1)/(4)A(2) conical intersection and reveal a new minimum with D(3h) symmetry that lies 147 kcal mol(-1) above the atom-diatom asymptote. All major topographical features of the potential energy surface are accurately described by the DMBE function, including the weakly bound van der Waals minima at large atom-diatom separations.

  20. High Energy Propulsion System (HEPS) Analysis

    DTIC Science & Technology

    1992-07-01

    PL-TR-92-3025 APL-TR-PLTR92305 D A254 343 92-3025 1111I1111lI lllilllllllllltlllllllNll1111rýlr HIGH ENERGY PROPULSION SYSTEMS (HEPS) ANALYSIS Robert...T. Nachtrieb OLAC-PLIRKFE Edwards AFB, CA 93523-5000 July 1992 DTIC ELECTE AUG13 1992 Final Report S A 92-22749 PHILLIPS LABORATORY Propulsion ...NUMBERS HIGH ENERGY PROPULSION SYSTEM (HEPS) ANALYSIS PE: 62302F PR: 3058 6. AUTHOR(S) TA: OOP6 ROBERT T. NACHTRIEB 7. PERFORMING ORGANIZATION NAME(S

  1. Analysis on energy efficiency in healthcare buildings.

    PubMed

    García-Sanz-Calcedo, Justo

    2014-01-01

    The aim of this paper is to analyze and quantify the average healthcare centres' energy behavior and estimate the possibilities of savings through the use of concrete measures to reduce their energy demand in Extremadura, Spain. It provides the average energy consumption of 55 healthcare centres sized between 500 and 3,500 m². The analysis evaluated data of electricity and fossil fuel energy consumption as well as water use and other energy-consuming devices. The energy solutions proposed to improve the efficiency are quantified and listed. The average annual energy consumption of a healthcare centre is 86.01 kWh/m², with a standard deviation of 16.8 kWh/m². The results show that an annual savings of €4.77/m² is possible. The potential to reduce the energy consumption of a healthcare centre of size 1,000 m² is 10,801 kWh by making an average investment of €11,601, thus saving €2,961/year with an average payback of 3.92 years.

  2. Portfolio Analysis of Renewable Energy Opportunities: Preprint

    SciTech Connect

    Richards, Allison; Deprizio, Jodi; Anderson, Kate; DiOrio, Nick; Elgqvist, Emma; Simpkins, Travis

    2016-11-01

    Time Warner Cable (TWC), now Charter Communications (CC), partnered with the National Renewable Energy Laboratory (NREL) to assess the technical and economic potential for solar photovoltaic (PV), wind, and ground-source heat-pump systems at 696 TWC facilities. NREL identified 306 sites where adding a renewable energy system would provide cost savings over the project life-cycle. In general, the top sites have some combination of high electricity rates ($0.16-$0.29/kWh), significant state incentives, and favorable net-metering policies. If all projects were implemented via third-party power purchase agreements, TWC/CC would save $37 million over 25 years and meet 10.5% of their energy consumption with renewable energy. This paper describes the portfolio screening methodology used to identify and prioritize renewable energy opportunities across the TWC sites, as well as a summary of the potential cost savings that may be realized by implementing these projects. This may provide a template for other companies interested in identifying and prioritizing renewable energy opportunities across a large number of geographically dispersed sites. Following this initial portfolio analysis, NREL will be conducting in-depth analysis of project development opportunities at ten sites and evaluating off-grid solutions that may enable carbon emission reduction and grid independence at select facilities.

  3. Developing a 3D constrained variational analysis method to obtain accurate gridded atmospheric vertical velocity and horizontal advections

    NASA Astrophysics Data System (ADS)

    Tang, S.; Zhang, M.

    2013-12-01

    Based on the constrained variational analysis (CVA) algorithm developed by Zhang and Lin (1997), a 3-dimensional (3D) version of CVA is developed. The new algorithm used gridded surface and TOA observations as constraints to adjust atmospheric state variables in each grid point to satisfy column-integrated mass, moisture and static energy conservation. From the process of adjustment a set of high-quality 3D large-scale forcing data (vertical velocity and horizontal advections) can be derived to drive Single-Column models (SCM), Cloud-Resolving Models (CRM) and Large-Eddy Simulations (LES) to evaluate and improve parameterizations. Since the 3D CVA can adjust gridded state variables from any data source with observed precipitation, radiation and surface fluxes, it also gives a potential possibility to use this algorithm in data assimilation system to assimilate precipitation and radiation data.

  4. 76 FR 64931 - Building Energy Codes Cost Analysis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ... of Energy Efficiency and Renewable Energy Building Energy Codes Cost Analysis AGENCY: Office of... the request for information on Building Energy Codes Cost Analysis published in the Federal Register... Energy Code Cost Analysis and provide docket number EERE-2011-BT-BC-0046. Comments may be submitted...

  5. Cross-impacts analysis development and energy policy analysis applications

    SciTech Connect

    Roop, J.M.; Scheer, R.M.; Stacey, G.S.

    1986-12-01

    Purpose of this report is to describe the cross-impact analysis process and microcomputer software developed for the Office of Policy, Planning, and Analysis (PPA) of DOE. First introduced in 1968, cross-impact analysis is a technique that produces scenarios of future conditions and possibilities. Cross-impact analysis has several unique attributes that make it a tool worth examining, especially in the current climate when the outlook for the economy and several of the key energy markets is uncertain. Cross-impact analysis complements the econometric, engineering, systems dynamics, or trend approaches already in use at DOE. Cross-impact analysis produces self-consistent scenarios in the broadest sense and can include interaction between the economy, technology, society and the environment. Energy policy analyses that couple broad scenarios of the future with detailed forecasting can produce more powerful results than scenario analysis or forecasts can produce alone.

  6. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service.

    PubMed

    Zou, Han; Jiang, Hao; Luo, Yiwen; Zhu, Jianjie; Lu, Xiaoxuan; Xie, Lihua

    2016-02-22

    The location and contextual status (indoor or outdoor) is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS) for individuals. In addition, optimizations of building management systems (BMS), such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO) detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS) easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption.

  7. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service

    PubMed Central

    Zou, Han; Jiang, Hao; Luo, Yiwen; Zhu, Jianjie; Lu, Xiaoxuan; Xie, Lihua

    2016-01-01

    The location and contextual status (indoor or outdoor) is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS) for individuals. In addition, optimizations of building management systems (BMS), such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO) detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS) easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption. PMID:26907295

  8. 76 FR 57982 - Building Energy Codes Cost Analysis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy Building Energy Codes Cost Analysis Correction In notice... components''. BILLING CODE 1505-01-P...

  9. Ring polymer molecular dynamics fast computation of rate coefficients on accurate potential energy surfaces in local configuration space: Application to the abstraction of hydrogen from methane.

    PubMed

    Meng, Qingyong; Chen, Jun; Zhang, Dong H

    2016-04-21

    To fast and accurately compute rate coefficients of the H/D + CH4 → H2/HD + CH3reactions, we propose a segmented strategy for fitting suitable potential energy surface (PES), on which ring-polymer molecular dynamics (RPMD) simulations are performed. On the basis of recently developed permutation invariant polynomial neural-network approach [J. Li et al., J. Chem. Phys. 142, 204302 (2015)], PESs in local configuration spaces are constructed. In this strategy, global PES is divided into three parts, including asymptotic, intermediate, and interaction parts, along the reaction coordinate. Since less fitting parameters are involved in the local PESs, the computational efficiency for operating the PES routine is largely enhanced by a factor of ∼20, comparing with that for global PES. On interaction part, the RPMD computational time for the transmission coefficient can be further efficiently reduced by cutting off the redundant part of the child trajectories. For H + CH4, good agreements among the present RPMD rates and those from previous simulations as well as experimental results are found. For D + CH4, on the other hand, qualitative agreement between present RPMD and experimental results is predicted.

  10. Ring polymer molecular dynamics fast computation of rate coefficients on accurate potential energy surfaces in local configuration space: Application to the abstraction of hydrogen from methane

    NASA Astrophysics Data System (ADS)

    Meng, Qingyong; Chen, Jun; Zhang, Dong H.

    2016-04-01

    To fast and accurately compute rate coefficients of the H/D + CH4 → H2/HD + CH3 reactions, we propose a segmented strategy for fitting suitable potential energy surface (PES), on which ring-polymer molecular dynamics (RPMD) simulations are performed. On the basis of recently developed permutation invariant polynomial neural-network approach [J. Li et al., J. Chem. Phys. 142, 204302 (2015)], PESs in local configuration spaces are constructed. In this strategy, global PES is divided into three parts, including asymptotic, intermediate, and interaction parts, along the reaction coordinate. Since less fitting parameters are involved in the local PESs, the computational efficiency for operating the PES routine is largely enhanced by a factor of ˜20, comparing with that for global PES. On interaction part, the RPMD computational time for the transmission coefficient can be further efficiently reduced by cutting off the redundant part of the child trajectories. For H + CH4, good agreements among the present RPMD rates and those from previous simulations as well as experimental results are found. For D + CH4, on the other hand, qualitative agreement between present RPMD and experimental results is predicted.

  11. Biomass compositional analysis for energy applications.

    PubMed

    Hames, Bonnie R

    2009-01-01

    In its broadest definition, biomass can be described as all material that was or is a part of a living organism. For renewable energy applications, however, the definition of biomass is usually limited to include only materials that are plant-derived such as agricultural residues (e.g., wheat straw, corn stover) by-products of industrial processes (e.g., sawdust, sugar cane bagasse, pulp residues, distillers grains), or dedicated energy crops (e.g., switchgrass, sorghum, Miscanthus, short-rotation woody crops). This chapter describes analytical methods developed to measure plant components with an emphasis on the measurement of components that are important for biomass conversion. The methods described here can be viewed as a portfolio of analytical methods, with consistent assumptions and compatible sample preparation steps, selected for simplicity, robust application, and the ability to obtain a summative mass closure on most samples that accurately identifies greater than 95% of the mass of a plant biomass sample. The portfolio of methods has been successfully applied to a wide variety of biomass feedstock as well as liquid and solid fractions of both thermochemical pretreatment and enzymatic saccharification (1).

  12. Energy Analysis Program. 1992 Annual report

    SciTech Connect

    Not Available

    1993-06-01

    The Program became deeply involved in establishing 4 Washington, D.C., project office diving the last few months of fiscal year 1942. This project office, which reports to the Energy & Environment Division, will receive the majority of its support from the Energy Analysis Program. We anticipate having two staff scientists and support personnel in offices within a few blocks of DOE. Our expectation is that this office will carry out a series of projects that are better managed closer to DOE. We also anticipate that our representation in Washington will improve and we hope to expand the Program, its activities, and impact, in police-relevant analyses. In spite of the growth that we have achieved, the Program continues to emphasize (1) energy efficiency of buildings, (2) appliance energy efficiency standards, (3) energy demand forecasting, (4) utility policy studies, especially integrated resource planning issues, and (5) international energy studies, with considerate emphasis on developing countries and economies in transition. These continuing interests are reflected in the articles that appear in this report.

  13. Simplified building energy analysis tool for architects

    NASA Astrophysics Data System (ADS)

    Chaisuparasmikul, Pongsak

    applicable to the earliest stage of design, where more informed analysis of possible alternatives could yield the most benefit and the greatest cost savings both economic and environmental. This is where computer modeling and simulation can really lead to better and energy efficient buildings. Both apply to internal environment and human comfort, and environmental impact from surroundings.

  14. Lac Courte Oreilles Energy Analysis Project

    SciTech Connect

    Leslie Isham; Denise Johnson

    2009-04-01

    and funding to do so will be sought. While we already are in ownership of a Hydro Dam it is currently not functioning to its full capacity we are seeking operation and maintenance firm proposals and funding sources. One of our biggest accomplishment this project gave us was our total Carbon Emissions 9989.45 tons, this will be the number that we will use to base our reductions from. It will help us achieve our goals we have set for ourselves in achieving the Kyoto Protocol and saving our Earth for our future generations. Another major accomplishment and lesson learned is we need to educate ourselves and our people on how to conserve energy to both impact the environment and our own budgets. The Lac Courte Oreilles (LCO) Energy Analysis Project will perform an energy audit to gather information on the Tribe's energy usage and determine the carbon emissions. By performing the audit we will be able to identify areas where conservation efforts are most viable and recommend policies that can be implemented. These steps will enable LCO to begin achieving the goals that have been set by the Tribal Governing Board and adopted through resolutions. The goals are to reduce emissions by 25% and to produce 25% of its energy using sustainable sources. The project objectives were very definitive to assist the Tribe in achieving its goals; reducing carbon emissions and obtaining a sustainable source of energy. The following were the outlined objectives: (1) Coordinate LCO's current and future conservation and renewable energy projects; (2) Establish working relationships with outside entities to share information and collaborate on future projects; (3) Complete energy audit and analyze LCO's energy load and carbon emissions; (4) Identify policy changes, education programs and conservation efforts which are appropriate for the LCO Reservation; and (5) Create a plan to identify the most cost effective renewable energy options for LCO.

  15. Accurate mode characterization of graded-index multimode fibers for the application of mode-noise analysis

    NASA Astrophysics Data System (ADS)

    Liu, Yueai; Rahman, B. M. A.; Ning, Ya Nong; Grattan, K. T. V.

    1995-03-01

    Guided modes in graded-index multimode optical fibers are accurately analyzed with the vector H-field finite-element method, aided by the use of the WKB method. As a result, exact mode-propagation constants and the corresponding modal eigenfield distributions are provided for the study of the modal noise that is due to the mode-coupling effect.

  16. Bifurcations analysis of turbulent energy cascade

    SciTech Connect

    Divitiis, Nicola de

    2015-03-15

    This note studies the mechanism of turbulent energy cascade through an opportune bifurcations analysis of the Navier–Stokes equations, and furnishes explanations on the more significant characteristics of the turbulence. A statistical bifurcations property of the Navier–Stokes equations in fully developed turbulence is proposed, and a spatial representation of the bifurcations is presented, which is based on a proper definition of the fixed points of the velocity field. The analysis first shows that the local deformation can be much more rapid than the fluid state variables, then explains the mechanism of energy cascade through the aforementioned property of the bifurcations, and gives reasonable argumentation of the fact that the bifurcations cascade can be expressed in terms of length scales. Furthermore, the study analyzes the characteristic length scales at the transition through global properties of the bifurcations, and estimates the order of magnitude of the critical Taylor-scale Reynolds number and the number of bifurcations at the onset of turbulence.

  17. Department of Defense Operational Energy Strategy: A Content Analysis of Energy Literature from 1973-2014

    DTIC Science & Technology

    2014-03-27

    Applications: Solar, Wind, Biomass, Geothermal , Hydrokinetic Energy , Biofuels and Synfuels, Fuel Cells, Microgrids, Smart meters, and Energy Efficiency...DEPARTMENT OF DEFENSE OPERATIONAL ENERGY STRATEGY: A CONTENT ANALYSIS OF ENERGY ...copyright protection in the United States. AFIT-ENS-14-M-26 DEPARTMENT OF DEFENSE OPERATIONAL ENERGY STRATEGY: A CONTENT ANALYSIS

  18. Human Energy Field: A Concept Analysis.

    PubMed

    Shields, Deborah; Fuller, Ann; Resnicoff, Marci; Butcher, Howard K; Frisch, Noreen

    2016-11-23

    The human energy field (HEF) as a phenomenon of interest across disciplines has gained increased attention over the 20th and 21st centuries. However, a concern has arisen that there is a lack of evidence to support the concept of the HEF as a phenomenon of interest to professional nurses and nursing practice. Using Chinn and Kramer's method of creating conceptual meaning, a concept analysis was conducted for the purpose of developing a conceptual definition of HEF. A systematic review of the literature using the CINAHL database yielded a total of 81 articles and text sources that were determined to be relevant to the concept analysis. The HEF is defined as a luminous field of energy that comprises a person, extends beyond the physical body, and is in a continuous mutual process with the environmental energy field. It is a vital energy that is a continuous whole and is recognized by its unique pattern; it is dynamic, creative, nonlinear, unpredictable, and flows in lower and higher frequencies. The balanced HEF is characterized by flow, rhythm, symmetry, and gentle vibration.

  19. Development of Next Generation Energy Audit Protocols for the Rapid and Advanced Analysis of Building Energy Use

    NASA Astrophysics Data System (ADS)

    Hartley, Christopher Ahlvin

    Current building energy auditing techniques are outdated and lack targeted, actionable information. These analyses only use one year's worth of monthly electricity and gas bills to define energy conservation and efficiency measures. These limited data sets cannot provide robust, directed energy reduction recommendations. The need is apparent for an overhaul of existing energy audit protocols to utilize all data that is available from the building's utility provider, installed energy management system (EMS), and sub-metering devices. This thesis analyzed the current state-of-the-art in energy audits, generated a next generation energy audit protocol, and conducted both audits types on four case study buildings to find out what additional information can be obtained from additional data sources and increased data gathering resolutions. Energy data from each case study building were collected using a variety of means including utility meters, whole building energy meters, EMS systems, and sub-metering devices. In addition to conducting an energy analysis for each case study building using the current and next generation energy audit protocols, two building energy models were created using the programs eQuest and EnergyPlus. The current and next generation energy audit protocol results were compared to one another upon completion. The results show that using the current audit protocols, only variations in season are apparent. Results from the developed next generation energy audit protocols show that in addition to seasonal variations, building heating, ventilation and air conditioning (HVAC) schedules, occupancy schedules, baseline and peak energy demand levels, and malfunctioning equipment can be found. This new protocol may also be used to quickly generate accurate building models because of the increased resolution that yields scheduling information. The developed next generation energy auditing protocol is scalable and can work for many building types across the

  20. Methodology for Validating Building Energy Analysis Simulations

    SciTech Connect

    Judkoff, R.; Wortman, D.; O'Doherty, B.; Burch, J.

    2008-04-01

    The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions.

  1. Scripted Building Energy Modeling and Analysis: Preprint

    SciTech Connect

    Hale, E.; Macumber, D.; Benne, K.; Goldwasser, D.

    2012-08-01

    Building energy modeling and analysis is currently a time-intensive, error-prone, and nonreproducible process. This paper describes the scripting platform of the OpenStudio tool suite (http://openstudio.nrel.gov) and demonstrates its use in several contexts. Two classes of scripts are described and demonstrated: measures and free-form scripts. Measures are small, single-purpose scripts that conform to a predefined interface. Because measures are fairly simple, they can be written or modified by inexperienced programmers.

  2. Nonlinear transient analysis via energy minimization

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.; Knight, N. F., Jr.

    1978-01-01

    The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose.

  3. Biomass energy analysis for crop dehydration

    SciTech Connect

    Whittier, J.P.; Haase, S.G.; Quinn, M.W.

    1994-12-31

    In 1994, an agricultural processing facility was constructed in southern New Mexico for spice and herb dehydration. Annual operational costs are dominated by energy costs, due primarily to the energy intensity of dehydration. A feasibility study was performed to determine whether the use of biomass resources as a feedstock for a cogeneration system would be an economical option. The project location allowed access to unusual biomass feedstocks including cotton gin trash, pecan shells and in-house residues. A resource assessment of the immediate project area determined that approximately 120,000 bone dry tons of biomass feedstocks are available annually. Technology characterization for the plant energy requirements indicated gasification systems offer fuel flexibility advantages over combustion systems although vendor support and commercial experience are limited. Regulatory siting considerations introduce a level of uncertainty because of a lack of a precedent in New Mexico for gasification technology and because vendors of commercial gasifiers have little experience operating such a facility nor gathering emission data. A public opinion survey indicated considerable support for renewable energy use and biomass energy utilization. However, the public opinion survey also revealed limited knowledge of biomass technologies and concerns regarding siting of a biomass facility within the geographic area. The economic analysis conducted for the study is based on equipment vendor quotations, and indicates there will be difficulty competing with current prices of natural gas.

  4. Energy Flow Analysis of Coupled Beams

    NASA Astrophysics Data System (ADS)

    Cho, P. E.; Bernhard, R. J.

    1998-04-01

    Energy flow analysis (EFA) is an analytical tool for prediction of the frequency-averaged vibrational response of built-up structures at high audible frequencies. The procedure is based on two developments; first, the derivation of the partial differential equations that govern the propagation of energy-related quantities in simple structural elements such as rods, beams, plates, and acoustic cavities; and second, the derivation of coupling relationships in terms of energy-related quantities that describe the transfer of energy for various joints (e.g., beam-to-beam, rod-to-beam, plate-to-plate, structure-to-acoustic field coupling). In this investigation, the energy flow coupling relationships at these joints for rods and beams are derived. EFA is used to predict the frequency-averaged vibrational response of a frame structure with a three-dimensional joint, where four wave types propagate in the structure. The predicted results of EFA are shown to be a good approximation of the frequency-averaged “exact” energetics, which are computed from classical displacement solutions.

  5. Analysis of lunar regolith thermal energy storage

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    1991-01-01

    The concept of using lunar regolith as a thermal energy storage medium was evaluated. The concept was examined by mathematically modeling the absorption and transfer of heat by the lunar regolith. Regolith thermal and physical properties were established through various sources as functions of temperature. Two cases were considered: a semi-infinite, constant temperature, cylindrical heat source embedded in a continuum of lunar regolith and a spherically shaped molten zone of lunar regolith set with an initial temperature profile. The cylindrical analysis was performed in order to examine the amount of energy which can be stored in the regolith during the day. At night, the cylinder acted as a perfect insulator. This cycling was performed until a steady state situation was reached in the surrounding regolith. It was determined that a cycling steady state occurs after approximately 15 day/night cycles. Results were obtained for cylinders of various diameters. The spherical molten zone analysis was performed to establish the amount of thermal energy, within the regolith, necessary to maintain some molten material throughout a nighttime period. This surrounding temperature profile was modeled after the cycling steady state temperature profile established by the cylindrical analysis. It was determined that a molten sphere diameter of 4.76 m is needed to maintain a core temperature near the low end of the melting temperature range throughout one nighttime period.

  6. Passivhaus: indoor comfort and energy dynamic analysis.

    NASA Astrophysics Data System (ADS)

    Guida, Antonella; Pagliuca, Antonello; Cardinale, Nicola; Rospi, Gianluca

    2013-04-01

    The research aims to verify the energy performance as well as the indoor comfort of an energy class A+ building, built so that the sum of the heat passive contributions of solar radiation, transmitted through the windows, and the heat generated inside the building, are adeguate to compensate for the envelope loss during the cold season. The building, located in Emilia Romagna (Italy), was built using a wooden structure, an envelope realized using a pinewood sandwich panels (transmittance U = 0.250 W/m2K) and, inside, a wool flax insulation layer and thermal window frame with low-emissivity glass (U = 0524 W/m2K). The building design and construction process has followed the guidelines set by "CasaClima". The building has been modeled in the code of dynamic calculation "Energy Plus" by the Design Builder application and divided it into homogenous thermal zones, characterized by winter indoor temperature set at 20 ° (+ / - 1 °) and summer indoor temperature set at 26 ° (+ / - 1 °). It has modeled: the envelope, as described above, the "free" heat contributions, the air conditioning system, the Mechanical Ventilation system as well as home automation solutions. The air conditioning system is an heat pump, able to guarantee an optimization of energy consumption (in fact, it uses the "free" heat offered by the external environment for conditioning indoor environment). As regards the air recirculation system, it has been used a mechanical ventilation system with internal heat cross-flow exchanger, with an efficiency equal to 50%. The domotic solutions, instead, regard a system for the control of windows external screening using reeds, adjustable as a function of incident solar radiation and a lighting management system adjusted automatically using a dimmer. A so realized building meets the requirement imposed from Italian standard UNI/TS 11300 1, UNI/TS 11300 2 and UNI/TS 11300 3. The analysis was performed according to two different configurations: in "spontaneous

  7. Full-Dimensional Potential Energy and Dipole Moment Surfaces of GeH4 Molecule and Accurate First-Principle Rotationally Resolved Intensity Predictions in the Infrared.

    PubMed

    Nikitin, A V; Rey, M; Rodina, A; Krishna, B M; Tyuterev, Vl G

    2016-11-17

    Nine-dimensional potential energy surface (PES) and dipole moment surface (DMS) of the germane molecule are constructed using extended ab initio CCSD(T) calculations at 19 882 points. PES analytical representation is determined as an expansion in nonlinear symmetry adapted products of orthogonal and internal coordinates involving 340 parameters up to eighth order. Minor empirical refinement of the equilibrium geometry and of four quadratic parameters of the PES computed at the CCSD(T)/aug-cc-pVQZ-DK level of the theory yielded the accuracy below 1 cm(-1) for all experimentally known vibrational band centers of five stable isotopologues of (70)GeH4, (72)GeH4, (73)GeH4, (74)GeH4, and (76)GeH4 up to 8300 cm(-1). The optimized equilibrium bond re = 1.517 594 Å is very close to best ab initio values. Rotational energies up to J = 15 are calculated using potential expansion in normal coordinate tensors with maximum errors of 0.004 and 0.0006 cm(-1) for (74)GeH4 and (76)GeH4. The DMS analytical representation is determined through an expansion in symmetry-adapted products of internal nonlinear coordinates involving 967 parameters up to the sixth order. Vibration-rotation line intensities of five stable germane isotopologues were calculated from purely ab initio DMS using nuclear motion variational calculations with a full account of the tetrahedral symmetry of the molecules. For the first time a good overall agreement of main absorption features with experimental rotationally resolved Pacific Northwest National Laboratory spectra was achieved in the entire range of 700-5300 cm(-1). It was found that very accurate description of state-dependent isotopic shifts is mandatory to correctly describe complex patterns of observed spectra at natural isotopic abundance resulting from the superposition of five stable isotopologues. The data obtained in this work will be made available through the TheoReTS information system.

  8. Accurate lithography hotspot detection based on principal component analysis-support vector machine classifier with hierarchical data clustering

    NASA Astrophysics Data System (ADS)

    Yu, Bei; Gao, Jhih-Rong; Ding, Duo; Zeng, Xuan; Pan, David Z.

    2015-01-01

    As technology nodes continue to shrink, layout patterns become more sensitive to lithography processes, resulting in lithography hotspots that need to be identified and eliminated during physical verification. We propose an accurate hotspot detection approach based on principal component analysis-support vector machine classifier. Several techniques, including hierarchical data clustering, data balancing, and multilevel training, are provided to enhance the performance of the proposed approach. Our approach is accurate and more efficient than conventional time-consuming lithography simulation and provides a high flexibility for adapting to new lithography processes and rules.

  9. Global sensitivity analysis in wind energy assessment

    NASA Astrophysics Data System (ADS)

    Tsvetkova, O.; Ouarda, T. B.

    2012-12-01

    Wind energy is one of the most promising renewable energy sources. Nevertheless, it is not yet a common source of energy, although there is enough wind potential to supply world's energy demand. One of the most prominent obstacles on the way of employing wind energy is the uncertainty associated with wind energy assessment. Global sensitivity analysis (SA) studies how the variation of input parameters in an abstract model effects the variation of the variable of interest or the output variable. It also provides ways to calculate explicit measures of importance of input variables (first order and total effect sensitivity indices) in regard to influence on the variation of the output variable. Two methods of determining the above mentioned indices were applied and compared: the brute force method and the best practice estimation procedure In this study a methodology for conducting global SA of wind energy assessment at a planning stage is proposed. Three sampling strategies which are a part of SA procedure were compared: sampling based on Sobol' sequences (SBSS), Latin hypercube sampling (LHS) and pseudo-random sampling (PRS). A case study of Masdar City, a showcase of sustainable living in the UAE, is used to exemplify application of the proposed methodology. Sources of uncertainty in wind energy assessment are very diverse. In the case study the following were identified as uncertain input parameters: the Weibull shape parameter, the Weibull scale parameter, availability of a wind turbine, lifetime of a turbine, air density, electrical losses, blade losses, ineffective time losses. Ineffective time losses are defined as losses during the time when the actual wind speed is lower than the cut-in speed or higher than the cut-out speed. The output variable in the case study is the lifetime energy production. Most influential factors for lifetime energy production are identified with the ranking of the total effect sensitivity indices. The results of the present

  10. Energy flow analysis of coupled structures

    NASA Astrophysics Data System (ADS)

    Cho, Phillip Eung-Ho

    1993-01-01

    Energy flow analysis (EFA) is an analytical tool for prediction of the frequency-averaged vibrational response of built-up structures at high audible frequencies. The procedure is based on two developments; firstly, the derivation of the partial differential equations that govern the propagation of energy-related quantities in simple structural elements such as rods, beams, plates, and acoustic cavities; secondly, the derivation of coupling relationships in terms of energy-related quantities that describe the transfer of energy for various joints (e.g., beam-to-beam, plate-to-plate, and structure-to acoustic field couplings). In this investigation, EFA is used to predict the vibrational response of various coupled structures. In the process of predicting the vibrational response of the coupled structures, the energy flow coupling relationships at the joints of these structures are derived. In addition, the finite element formulation of the governing energy equations are developed. Because the energy density is discontinuous at the joint, a special global assembly procedure is developed to assemble the finite element matrix equations into global matrix equations. The global matrix assembly procedure is predicated on the development of joint element matrix equations using energy flow coupling relationships for various structural joints. The results predicted by EFA for a frame structure with a three-dimensional joint, where four wave types propagate in the structure, are shown to be a reasonable approximation of the frequency-averaged 'exact' energetics, which are computed from classical displacement solutions. The accuracy of the results predicted by EFA increased with high mode count and modal overlap factor or high non-dimensional wavenumber band and non-dimensional damped wavenumber band in the frequency band of interest. An experimental investigation of vibrational response of a light truck frame structure was performed to verify the results of EFA when applied

  11. Comprehensive energy analysis of a near zero energy home

    NASA Astrophysics Data System (ADS)

    Jannumahanthi, Madhuri

    Buildings consume nearly 40% of the entire energy used in the United States. To reduce the residential energy consumption, the Department of Energy (DOE) in partnership with Building America is evaluating various energy efficient technologies that might be integrated to produce a Zero Energy Home (ZEH). The research presented in this thesis focuses on evaluating the energy use of individual energy saving components and a near ZEH system in Salt Lake City, Utah. A state-of-the-art software tool, DesignBuilder, which employs an EnergyPlus simulation engine, was used to evaluate the performance of the prototype models. The major energy saving features in the house included photovoltaic thermal (PVT) panels; the hybrid solar panels that combine PV and solar thermal panel technology in a single entity; OASys, a new evaporative cooling unit that has a SEER 40+; structural insulated panels (SIPs); and a hydronic furnace. With real time data acquisition, the performance of the individual components and the near ZEH system was studied. PVT performs with nearly 20% greater efficiency than a conventional photovoltaic (PV) system. OASys reduces the cooling energy use by 60% in comparison with a regular vapor compression air conditioning system. Simulation results indicate 30% reduced energy use with SIPs. The hydronic furnace provides comfortable heating with 2% of the total heating energy as preheat to the water heater. The high efficiency water heater has a peak monthly efficiency of 83%. The actual data usage indicates that the energy efficient house has nearly 50% reduced energy use over a simulated model without the energy saving features and 60% fewer carbon dioxide emissions than a regular house.

  12. Energy analysis of convectively induced wind perturbations

    NASA Technical Reports Server (NTRS)

    Fuelberg, Henry E.; Buechler, Dennis E.

    1989-01-01

    Budgets of divergent and rotational components of kinetic energy (KD and KR) are examined for four upper level wind speed maxima that develop during the fourth Atmospheric Variability Experiment (AVE IV) and the first AVE-Severe Environmental Storms and Mesoscale Experiment (AVE-SESAME I). A similar budget analysis is performed for a low-level jet stream during AVE-SESAME I. The energetics of the four upper level speed maxima is found to have several similarities. The dominant source of KD is cross-contour flow by the divergent wind, and KD provides a major source of KR via a conversion process. Conversion from available potential energy provides an additional source of KR in three of the cases. Horizontal maps reveal that the conversions involving KD are maximized in regions poleward of the convection. Low-level jet development during AVE-SESAME I appears to be assisted by convective activity to the west.

  13. Energy decomposition analysis in an adiabatic picture.

    PubMed

    Mao, Yuezhi; Horn, Paul R; Head-Gordon, Martin

    2017-02-22

    Energy decomposition analysis (EDA) of electronic structure calculations has facilitated quantitative understanding of diverse intermolecular interactions. Nevertheless, such analyses are usually performed at a single geometry and thus decompose a "single-point" interaction energy. As a result, the influence of the physically meaningful EDA components on the molecular structure and other properties are not directly obtained. To address this gap, the absolutely localized molecular orbital (ALMO)-EDA is reformulated in an adiabatic picture, where the frozen, polarization, and charge transfer energy contributions are defined as energy differences between the stationary points on different potential energy surfaces (PESs), which are accessed by geometry optimizations at the frozen, polarized and fully relaxed levels of density functional theory (DFT). Other molecular properties such as vibrational frequencies can thus be obtained at the stationary points on each PES. We apply the adiabatic ALMO-EDA to different configurations of the water dimer, the water-Cl(-) and water-Mg(2+)/Ca(2+) complexes, metallocenes (Fe(2+), Ni(2+), Cu(2+), Zn(2+)), and the ammonia-borane complex. This method appears to be very useful for unraveling how physical effects such as polarization and charge transfer modulate changes in molecular properties induced by intermolecular interactions. As an example of the insight obtained, we find that a linear hydrogen bond geometry for the water dimer is preferred even without the presence of polarization and charge transfer, while the red shift in the OH stretch frequency is primarily a charge transfer effect; by contrast, a near-linear geometry for the water-chloride hydrogen bond is achieved only when charge transfer is allowed.

  14. Issues in International Energy Consumption Analysis: Canadian Energy Demand

    EIA Publications

    2015-01-01

    The residential sector is one of the main end-use sectors in Canada accounting for 16.7% of total end-use site energy consumption in 2009 (computed from NRCan 2012. pp, 4-5). In this year, the residential sector accounted for 54.5% of buildings total site energy consumption. Between 1990 and 2009, Canadian household energy consumption grew by less than 11%. Nonetheless, households contributed to 14.6% of total energy-related greenhouse gas emissions in Canada in 2009 (computed from NRCan 2012). This is the U.S. Energy Information Administration’s second study to help provide a better understanding of the factors impacting residential energy consumption and intensity in North America (mainly the United States and Canada) by using similar methodology for analyses in both countries.

  15. Rapid and accurate detection of the CFTR gene mutation 1811+1.6 kbA>G by real-time fluorescence resonance energy transfer PCR.

    PubMed

    Reboul, Marie-Pierre; Higueret, Laurent; Biteau, Nicolas; Iron, Albert

    2005-10-01

    The CFTR gene mutation 1811+1.6 kbA>G has been reported as associated with a severe phenotype of cystic fibrosis with pancreatic insufficiency. This mutation has been identified as a rather common one in the South West of France and in the Iberian Peninsula. Because of the precise geographical origin of the subjects and its frequency, the mutation has to be investigated with accuracy. We have developed an original real-time Fluorescence Resonance Energy Transfer (FRET) PCR assay for genotyping the mutation 1811+1.6 kbA>G. It is based on the amplification of a region spanning the mutation with simultaneous detection of the amplicon by hybridization with a bi-probe followed by a melting curve analysis. The results obtained are identical with those resulting from either restriction fragment length polymorphism analysis or sequencing. The distinction between the wild type and the mutation 1811+1.6 kbA>G is easy because the corresponding melting points shows a difference of 6 or 9.5 degrees C depending on the associated SNP A/T located 16 bp downstream. We demonstrated that a FRET assay showed enough sensitivity to discriminate between two nucleotide polymorphisms (SNPs) in the sequence of the sensor. In conclusion, this method is specific, fast, easy to perform, reproducible, inexpensive as it uses only one bi-probe and well adapted to daily practice.

  16. Recent advances in statistical energy analysis

    NASA Technical Reports Server (NTRS)

    Heron, K. H.

    1992-01-01

    Statistical Energy Analysis (SEA) has traditionally been developed using modal summation and averaging approach, and has led to the need for many restrictive SEA assumptions. The assumption of 'weak coupling' is particularly unacceptable when attempts are made to apply SEA to structural coupling. It is now believed that this assumption is more a function of the modal formulation rather than a necessary formulation of SEA. The present analysis ignores this restriction and describes a wave approach to the calculation of plate-plate coupling loss factors. Predictions based on this method are compared with results obtained from experiments using point excitation on one side of an irregular six-sided box structure. Conclusions show that the use and calculation of infinite transmission coefficients is the way forward for the development of a purely predictive SEA code.

  17. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1989-01-01

    An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

  18. Cost analysis of energy storage systems for electric utility applications

    SciTech Connect

    Akhil, A.; Swaminathan, S.; Sen, R.K.

    1997-02-01

    Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Energy Storage System Analysis and Development Department at Sandia National Laboratories (SNL) conducted a cost analysis of energy storage systems for electric utility applications. The scope of the study included the analysis of costs for existing and planned battery, SMES, and flywheel energy storage systems. The analysis also identified the potential for cost reduction of key components.

  19. A highly sensitive and accurate gene expression analysis by sequencing ("bead-seq") for a single cell.

    PubMed

    Matsunaga, Hiroko; Goto, Mari; Arikawa, Koji; Shirai, Masataka; Tsunoda, Hiroyuki; Huang, Huan; Kambara, Hideki

    2015-02-15

    Analyses of gene expressions in single cells are important for understanding detailed biological phenomena. Here, a highly sensitive and accurate method by sequencing (called "bead-seq") to obtain a whole gene expression profile for a single cell is proposed. A key feature of the method is to use a complementary DNA (cDNA) library on magnetic beads, which enables adding washing steps to remove residual reagents in a sample preparation process. By adding the washing steps, the next steps can be carried out under the optimal conditions without losing cDNAs. Error sources were carefully evaluated to conclude that the first several steps were the key steps. It is demonstrated that bead-seq is superior to the conventional methods for single-cell gene expression analyses in terms of reproducibility, quantitative accuracy, and biases caused during sample preparation and sequencing processes.

  20. Analysis of algebraic reconstruction technique for accurate imaging of gas temperature and concentration based on tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Hui-Hui, Xia; Rui-Feng, Kan; Jian-Guo, Liu; Zhen-Yu, Xu; Ya-Bai, He

    2016-06-01

    An improved algebraic reconstruction technique (ART) combined with tunable diode laser absorption spectroscopy(TDLAS) is presented in this paper for determining two-dimensional (2D) distribution of H2O concentration and temperature in a simulated combustion flame. This work aims to simulate the reconstruction of spectroscopic measurements by a multi-view parallel-beam scanning geometry and analyze the effects of projection rays on reconstruction accuracy. It finally proves that reconstruction quality dramatically increases with the number of projection rays increasing until more than 180 for 20 × 20 grid, and after that point, the number of projection rays has little influence on reconstruction accuracy. It is clear that the temperature reconstruction results are more accurate than the water vapor concentration obtained by the traditional concentration calculation method. In the present study an innovative way to reduce the error of concentration reconstruction and improve the reconstruction quality greatly is also proposed, and the capability of this new method is evaluated by using appropriate assessment parameters. By using this new approach, not only the concentration reconstruction accuracy is greatly improved, but also a suitable parallel-beam arrangement is put forward for high reconstruction accuracy and simplicity of experimental validation. Finally, a bimodal structure of the combustion region is assumed to demonstrate the robustness and universality of the proposed method. Numerical investigation indicates that the proposed TDLAS tomographic algorithm is capable of detecting accurate temperature and concentration profiles. This feasible formula for reconstruction research is expected to resolve several key issues in practical combustion devices. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61205151), the National Key Scientific Instrument and Equipment Development Project of China (Grant

  1. Double calibration: an accurate, reliable and easy-to-use method for 3D scapular motion analysis.

    PubMed

    Brochard, Sylvain; Lempereur, Mathieu; Rémy-Néris, Olivier

    2011-02-24

    The most recent non-invasive methods for the recording of scapular motion are based on an acromion marker (AM) set and a single calibration (SC) of the scapula in a resting position. However, this method fails to accurately measure scapular kinematics above 90° of arm elevation, due to soft tissue artifacts of the skin and muscles covering the acromion. The aim of this study was to evaluate the accuracy, and inter-trial and inter-session repeatability of a double calibration method (DC) in comparison with SC. The SC and DC data were measured with an optoelectronic system during arm flexion and abduction at different angles of elevation (0-180°). They were compared with palpation of the scapula using a scapula locator. DC data was not significantly different from palpation for 5/6 axes of rotation tested (Y, X, and Z in abduction and flexion), where as SC showed significant differences for 5/6 axes. The root mean square errors ranged from 2.96° to 4.48° for DC and from 6° to 9.19° for SC. The inter-trial repeatability was good to excellent for SC and DC. The inter-session repeatability was moderate to excellent for SC and moderate to good for DC. Coupling AM and DC is an easy-to-use method, which yields accurate and reliable measurements of scapular kinematics for the complete range of arm motion. It can be applied to the measurement of shoulder motion in many fields (sports, orthopaedics, and rehabilitation), especially when large ranges of arm motion are required.

  2. 76 FR 56413 - Building Energy Codes Cost Analysis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-13

    ... of Energy Efficiency and Renewable Energy Building Energy Codes Cost Analysis AGENCY: Office of... changes to residential building energy codes. DOE supports the development of the International Code Council's (ICC) International Energy Conservation Code (IECC), the national model code adopted by...

  3. Statistical Energy Analysis (SEA) and Energy Finite Element Analysis (EFEA) Predictions for a Floor-Equipped Composite Cylinder

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Schiller, Noah H.; Cabell, Randolph H.

    2011-01-01

    Comet Enflow is a commercially available, high frequency vibroacoustic analysis software founded on Energy Finite Element Analysis (EFEA) and Energy Boundary Element Analysis (EBEA). Energy Finite Element Analysis (EFEA) was validated on a floor-equipped composite cylinder by comparing EFEA vibroacoustic response predictions with Statistical Energy Analysis (SEA) and experimental results. Statistical Energy Analysis (SEA) predictions were made using the commercial software program VA One 2009 from ESI Group. The frequency region of interest for this study covers the one-third octave bands with center frequencies from 100 Hz to 4000 Hz.

  4. Residual energy applications program systems analysis report

    SciTech Connect

    Yngve, P.W.

    1980-10-01

    Current DOE plans call for building an Energy Applied Systems Test (EAST) Facility at the Savannah River Plant in close proximity to the 140 to 150/sup 0/F waste heat from one of several operating nuclear reactors. The waste water flow from each reactor, approximately 165,000 gpm, provides a unique opportunity to test the performance and operating characteristics of large-scale waste heat power generation and heat pump system concepts. This report provides a preliminary description of the potential end-use market, parametric data on heat pump and the power generation system technology, a preliminary listing of EAST Facility requirements, and an example of an integrated industrial park utilizing the technology to maximize economic pay back. The parametric heat pump analysis concluded that dual-fluid Rankine cycle heat pumps with capacities as high as 400 x 10/sup 6/ Btu/h, can utilize large sources of low temperature residual heat to provide 300/sup 0/F saturatd steam for an industrial park. The before tax return on investment for this concept is 36.2%. The analysis also concluded that smaller modular heat pumps could fulfill the same objective while sacrificing only a moderate rate of return. The parametric power generation analysis concluded that multi-pressure Rankine cycle systems not only are superior to single pressure systems, but can also be developed for large systems (approx. = 17 MW/sub e/). This same technology is applicable to smaller systems at the sacrifice of higher investment per unit output.

  5. Virial theorem in the Kohn-Sham density-functional theory formalism: accurate calculation of the atomic quantum theory of atoms in molecules energies.

    PubMed

    Rodríguez, Juan I; Ayers, Paul W; Götz, Andreas W; Castillo-Alvarado, F L

    2009-07-14

    A new approach for computing the atom-in-molecule [quantum theory of atoms in molecule (QTAIM)] energies in Kohn-Sham density-functional theory is presented and tested by computing QTAIM energies for a set of representative molecules. In the new approach, the contribution for the correlation-kinetic energy (T(c)) is computed using the density-functional theory virial relation. Based on our calculations, it is shown that the conventional approach where atomic energies are computed using only the noninteracting part of the kinetic energy might be in error by hundreds of kJ/mol.

  6. Liver steatosis in pre-transplant liver biopsies can be quantified rapidly and accurately by nuclear magnetic resonance analysis.

    PubMed

    Bertram, Stefanie; Myland, Cathrin; Swoboda, Sandra; Gallinat, Anja; Minor, Thomas; Lehmann, Nils; Thie, Michael; Kälsch, Julia; Pott, Leona; Canbay, Ali; Bajanowski, Thomas; Reis, Henning; Paul, Andreas; Baba, Hideo A

    2017-02-01

    Donor livers marginally acceptable or acceptable according to extended criteria are more frequently transplanted due to the growing discrepancy between demand and availability of donor organs. One type of marginally acceptable graft is a steatotic donor liver, because it is more sensitive to ischemia-reperfusion injury. Thus, quantitative assessment of steatosis is crucial prior to liver transplantation. Extent of steatosis of 49 pre-reperfusion liver biopsies from patients who received orthotopic liver transplantation was assessed by three techniques: semi-quantitative histological evaluation, computerized histomorphometry, and NMR-based estimation of fat content. The findings were correlated to clinical data and to histological examination of corresponding post-reperfusion biopsies for quantification of ischemia-reperfusion injury. We found that values obtained through all three assessment methods were positively correlated. None of the values obtained by the three applied methods correlated with clinical outcome or extent of ischemia-reperfusion injury. Quantitative evaluation of steatosis by NMR yields results comparable to histological and morphometrical assessment. This technique is rapid (<5 min), accurately quantifies fat in donor livers, and provides results that can be used when evaluation by a pathologist is not available.

  7. Fibre Diffraction Analysis of Skin Offers a Very Early and Extremely Accurate Diagnostic Test for Prostate Cancer

    DOE PAGES

    James, Veronica J.; O’Malley Ford, Judith M.

    2014-01-01

    Double blind analysis of a batch of thirty skin tissue samples from potential prostate cancer sufferers correctly identified all “control” patients, patients with high and low grade prostate cancers, the presence of benign prostate hyperplasia (BPH), perineural invasions, and the one lymphatic invasion. Identification was by analysis of fibre diffraction patterns interpreted using a schema developed from observations in nine previous studies. The method, schema, and specific experiment results are reported in this paper, with some implications then drawn.

  8. Energy Performance Analysis of Ultra-Efficient Homes at Solar Decathlon 2013

    NASA Astrophysics Data System (ADS)

    Garkhail, Rahul

    The objective of this thesis is to investigate the various types of energy end-uses to be expected in future high efficiency single family residences. For this purpose, this study has analyzed monitored data from 14 houses in the 2013 Solar Decathlon competition, and segregates the energy consumption patterns in various residential end-uses (such as lights, refrigerators, washing machines, ...). The analysis was not straight-forward since these homes were operated according to schedules previously determined by the contest rules. The analysis approach allowed the isolation of the comfort energy use by the Heating, Venting and Cooling (HVAC) systems. HVAC are the biggest contributors to energy consumption during operation of a building, and therefore are a prime concern for energy performance during the building design and the operation. Both steady state and dynamic models of comfort energy use which take into account variations in indoor and outdoor temperatures, solar radiation and thermal mass of the building were explicitly considered. Steady State Inverse Models are frequently used for thermal analysis to evaluate HVAC energy performance. These are fast, accurate, offer great flexibility for mathematical modifications and can be applied to a variety of buildings. The results are presented as a horizontal study that compares energy consumption across homes to arrive at a generic rather than unique model - to be used in future discussions in the context of ultra efficient homes. It is suggested that similar analyses of the energy-use data that compare the performance of variety of ultra efficient technologies be conducted to provide more accurate indications of the consumption by end use for future single family residences. These can be used alongside the Residential Energy Consumption Survey (RECS) and the Leading Indicator for Remodeling Activity (LIRA) indices to assist in planning and policy making related to residential energy sector.

  9. Energy component analysis of π interactions.

    PubMed

    Sherrill, C David

    2013-04-16

    Fundamental features of biomolecules, such as their structure, solvation, and crystal packing and even the docking of drugs, rely on noncovalent interactions. Theory can help elucidate the nature of these interactions, and energy component analysis reveals the contributions from the various intermolecular forces: electrostatics, London dispersion terms, induction (polarization), and short-range exchange-repulsion. Symmetry-adapted perturbation theory (SAPT) provides one method for this type of analysis. In this Account, we show several examples of how SAPT provides insight into the nature of noncovalent π-interactions. In cation-π interactions, the cation strongly polarizes electrons in π-orbitals, leading to substantially attractive induction terms. This polarization is so important that a cation and a benzene attract each other when placed in the same plane, even though a consideration of the electrostatic interactions alone would suggest otherwise. SAPT analysis can also support an understanding of substituent effects in π-π interactions. Trends in face-to-face sandwich benzene dimers cannot be understood solely in terms of electrostatic effects, especially for multiply substituted dimers, but SAPT analysis demonstrates the importance of London dispersion forces. Moreover, detailed SAPT studies also reveal the critical importance of charge penetration effects in π-stacking interactions. These effects arise in cases with substantial orbital overlap, such as in π-stacking in DNA or in crystal structures of π-conjugated materials. These charge penetration effects lead to attractive electrostatic terms where a simpler analysis based on atom-centered charges, electrostatic potential plots, or even distributed multipole analysis would incorrectly predict repulsive electrostatics. SAPT analysis of sandwich benzene, benzene-pyridine, and pyridine dimers indicates that dipole/induced-dipole terms present in benzene-pyridine but not in benzene dimer are relatively

  10. Accurate CpG and non-CpG cytosine methylation analysis by high-throughput locus-specific pyrosequencing in plants.

    PubMed

    How-Kit, Alexandre; Daunay, Antoine; Mazaleyrat, Nicolas; Busato, Florence; Daviaud, Christian; Teyssier, Emeline; Deleuze, Jean-François; Gallusci, Philippe; Tost, Jörg

    2015-07-01

    Pyrosequencing permits accurate quantification of DNA methylation of specific regions where the proportions of the C/T polymorphism induced by sodium bisulfite treatment of DNA reflects the DNA methylation level. The commercially available high-throughput locus-specific pyrosequencing instruments allow for the simultaneous analysis of 96 samples, but restrict the DNA methylation analysis to CpG dinucleotide sites, which can be limiting in many biological systems. In contrast to mammals where DNA methylation occurs nearly exclusively on CpG dinucleotides, plants genomes harbor DNA methylation also in other sequence contexts including CHG and CHH motives, which cannot be evaluated by these pyrosequencing instruments due to software limitations. Here, we present a complete pipeline for accurate CpG and non-CpG cytosine methylation analysis at single base-resolution using high-throughput locus-specific pyrosequencing. The devised approach includes the design and validation of PCR amplification on bisulfite-treated DNA and pyrosequencing assays as well as the quantification of the methylation level at every cytosine from the raw peak intensities of the Pyrograms by two newly developed Visual Basic Applications. Our method presents accurate and reproducible results as exemplified by the cytosine methylation analysis of the promoter regions of two Tomato genes (NOR and CNR) encoding transcription regulators of fruit ripening during different stages of fruit development. Our results confirmed a significant and temporally coordinated loss of DNA methylation on specific cytosines during the early stages of fruit development in both promoters as previously shown by WGBS. The manuscript describes thus the first high-throughput locus-specific DNA methylation analysis in plants using pyrosequencing.

  11. Nuclear-labeling index analysis (NLIA), a software package used to perform accurate automation of cell nuclear-labeling index analysis on immunohistochemically stained rat liver samples.

    PubMed

    Xu, Y H; Sattler, G L; Edwards, H; Pitot, H C

    2000-08-01

    The nuclear labeling index (labeled nuclei/100 nuclei) and the apoptotic index (apoptotic cells/100 cells) are important parameters of cell growth and death. Automatic counting of labeled nuclei is desirable since manual counting is tedious, time-consuming, and with a greater potential for inaccuracies. A nuclear-labeling index analysis (NLIA) software package was developed in this laboratory to perform the counting process automatically and accurately. This software package consists of an application program NLIA and a set of macros for obtaining nuclear data that is used in Scion Image. It is designed to work cooperatively with Scion Image, Adobe Photoshop, and Microsoft Office. NLIA has two basic functions: building nuclear data files and analyzing nuclear data. A color image captured from an immunohistochemically stained or autoradiographic sample is loaded into NLIA. Nuclear data can be entered into the program manually, automatically, or in combination. In the manual data entering mode, NLIA acts as an object-counting tool, while in the automatic mode it acts as a data picker: picking up the data generated by Scion Image into memory. A method to enter nuclear data (both labeled nuclei and unlabeled nuclei) in the automatic mode is described. The color image is processed in Adobe Photoshop, where the interested color ranges are selected and separated. These are then analyzed in Scion Image with the help of the macros for obtaining nuclear data. Since the advanced particle analysis function is used, the counting process is automatic and rapid. Data from thousands of nuclei can be obtained within seconds. To ensure the accuracy of the analysis, a nuclear data checking and edit feature is employed in NLIA: results of computer-generated counting can be compared with the original color image by overlaying the plot of counting results onto the original color image. In this way any computer counting mistakes can be easily discovered and corrected by the operator

  12. Sewage sludge toxicity assessment using earthworm Eisenia fetida: can biochemical and histopathological analysis provide fast and accurate insight?

    PubMed

    Babić, S; Barišić, J; Malev, O; Klobučar, G; Popović, N Topić; Strunjak-Perović, I; Krasnići, N; Čož-Rakovac, R; Klobučar, R Sauerborn

    2016-06-01

    Sewage sludge (SS) is a complex organic by-product of wastewater treatment plants. Deposition of large amounts of SS can increase the risk of soil contamination. Therefore, there is an increasing need for fast and accurate assessment of SS toxic potential. Toxic effects of SS were tested on earthworm Eisenia fetida tissue, at the subcellular and biochemical level. Earthworms were exposed to depot sludge (DS) concentration ratio of 30 or 70 %, to undiluted and to 100 and 10 times diluted active sludge (AS). The exposure to DS lasted for 24/48 h (acute exposure), 96 h (semi-acute exposure) and 7/14/28 days (sub-chronic exposure) and 48 h for AS. Toxic effects were tested by the measurements of multixenobiotic resistance mechanism (MXR) activity and lipid peroxidation levels, as well as the observation of morphological alterations and behavioural changes. Biochemical markers confirmed the presence of MXR inhibitors in the tested AS and DS and highlighted the presence of SS-induced oxidative stress. The MXR inhibition and thiobarbituric acid reactive substance (TBARS) concentration in the whole earthworm's body were higher after the exposition to lower concentration of the DS. Furthermore, histopathological changes revealed damage to earthworm body wall tissue layers as well as to the epithelial and chloragogen cells in the typhlosole region. These changes were proportional to SS concentration in tested soils and to exposure duration. Obtained results may contribute to the understanding of SS-induced toxic effects on terrestrial invertebrates exposed through soil contact and to identify defence mechanisms of earthworms.

  13. Can free energy calculations be fast and accurate at the same time? Binding of low-affinity, non-peptide inhibitors to the SH2 domain of the src protein

    NASA Astrophysics Data System (ADS)

    Chipot, Christophe; Rozanska, Xavier; Dixit, Surjit B.

    2005-11-01

    The usefulness of free-energy calculations in non-academic environments, in general, and in the pharmaceutical industry, in particular, is a long-time debated issue, often considered from the angle of cost/performance criteria. In the context of the rational drug design of low-affinity, non-peptide inhibitors to the SH2 domain of the pp60src tyrosine kinase, the continuing difficulties encountered in an attempt to obtain accurate free-energy estimates are addressed. free-energy calculations can provide a convincing answer, assuming that two key-requirements are fulfilled: (i) thorough sampling of the configurational space is necessary to minimize the statistical error, hence raising the question: to which extent can we sacrifice the computational effort, yet without jeopardizing the precision of the free-energy calculation? (ii) the sensitivity of binding free-energies to the parameters utilized imposes an appropriate parametrization of the potential energy function, especially for non-peptide molecules that are usually poorly described by multipurpose macromolecular force fields. Employing the free-energy perturbation method, accurate ranking, within ±0.7 kcal/mol, is obtained in the case of four non-peptide mimes of a sequence recognized by the pp60src SH2 domain.

  14. Current Work in Energy Analysis (Energy Analysis Program -1996 Annual Report)

    SciTech Connect

    Energy Analysis Program

    1998-03-01

    This report describes the work that Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory has been doing most recently. One of our proudest accomplishments is the publication of Scenarios of U.S. Carbon Reductions, an analysis of the potential of energy technologies to reduce carbon emissions in the U.S. This analysis played a key role in shaping the U.S. position on climate change in the Kyoto Protocol negotiations. Our participation in the fundamental characterization of the climate change issue by the IPCC is described. We are also especially proud of our study of ''leaking electricity,'' which is stimulating an international campaign for a one-watt ceiling for standby electricity losses from appliances. This ceiling has the potential to save two-thirds of the 5% of U.S. residential electricity currently expended on standby losses. The 54 vignettes contained in the following pages summarize results of research. activities ranging in scale from calculating the efficacy of individual lamp ballasts to estimating the cost-effectiveness of the national ENERGY STAR{reg_sign} labeling program, and ranging in location from a scoping study of energy-efficiency market transformation in California to development of an energy-efficiency project in the auto parts industry in Shandong Province, China. These are the intellectual endeavors of a talented team of researchers dedicated to public service.

  15. Analysis Insights: Energy Storage - Possibilities for Expanding Electric Grid Flexibility

    SciTech Connect

    2016-02-01

    NREL Analysis Insights mines our body of analysis work to synthesize topical insights and key findings. In this issue, we explore energy storage and the role it is playing and could potentially play in increasing grid flexibility and renewable energy integration. We explore energy storage as one building block for a more flexible power system, policy and R and D as drivers of energy storage deployment, methods for valuing energy storage in grid applications, ways that energy storage supports renewable integration, and emerging opportunities for energy storage in the electric grid.

  16. Accurate identification of fastidious Gram-negative rods: integration of both conventional phenotypic methods and 16S rRNA gene analysis

    PubMed Central

    2013-01-01

    Background Accurate identification of fastidious Gram-negative rods (GNR) by conventional phenotypic characteristics is a challenge for diagnostic microbiology. The aim of this study was to evaluate the use of molecular methods, e.g., 16S rRNA gene sequence analysis for identification of fastidious GNR in the clinical microbiology laboratory. Results A total of 158 clinical isolates covering 20 genera and 50 species isolated from 1993 to 2010 were analyzed by comparing biochemical and 16S rRNA gene sequence analysis based identification. 16S rRNA gene homology analysis identified 148/158 (94%) of the isolates to species level, 9/158 (5%) to genus and 1/158 (1%) to family level. Compared to 16S rRNA gene sequencing as reference method, phenotypic identification correctly identified 64/158 (40%) isolates to species level, mainly Aggregatibacter aphrophilus, Cardiobacterium hominis, Eikenella corrodens, Pasteurella multocida, and 21/158 (13%) isolates correctly to genus level, notably Capnocytophaga sp.; 73/158 (47%) of the isolates were not identified or misidentified. Conclusions We herein propose an efficient strategy for accurate identification of fastidious GNR in the clinical microbiology laboratory by integrating both conventional phenotypic methods and 16S rRNA gene sequence analysis. We conclude that 16S rRNA gene sequencing is an effective means for identification of fastidious GNR, which are not readily identified by conventional phenotypic methods. PMID:23855986

  17. Accurate high level ab initio-based global potential energy surface and dynamics calculations for ground state of CH{sub 2}{sup +}

    SciTech Connect

    Li, Y. Q.; Zhang, P. Y.; Han, K. L.

    2015-03-28

    A global many-body expansion potential energy surface is reported for the electronic ground state of CH{sub 2}{sup +} by fitting high level ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pV6Z basis set. The topographical features of the new global potential energy surface are examined in detail and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. In turn, in order to validate the potential energy surface, a test theoretical study of the reaction CH{sup +}(X{sup 1}Σ{sup +})+H({sup 2}S)→C{sup +}({sup 2}P)+H{sub 2}(X{sup 1}Σ{sub g}{sup +}) has been carried out with the method of time dependent wavepacket on the title potential energy surface. The total integral cross sections and the rate coefficients have been calculated; the results determined that the new potential energy surface can both be recommended for dynamics studies of any type and as building blocks for constructing the potential energy surfaces of larger C{sup +}/H containing systems.

  18. Training Manual for the Energy Conservation Analysis Project.

    ERIC Educational Resources Information Center

    Massachusetts Univ., Amherst. Cooperative Extension Service.

    This document is the Massachusetts Energy Extension Service training manual for Residential Energy Auditors. This manual is part of a four-week program to train persons to perform home energy audits and was developed under the Energy Conservation Analysis Project (ECAP) at the University of Massachusetts. The chapter titles include: (1) Project…

  19. Well-to-Wheels Analysis of Advanced Fuel/Vehicle Systems: A North American Study of Energy Use, Greenhouse Gas Emissions, and Criteria Pollutant Emissions

    SciTech Connect

    Brinkman, Norman; Wang, Michael; Weber, Trudy; Darlington, Thomas

    2005-05-01

    An accurate assessment of future fuel/propulsion system options requires a complete vehicle fuel-cycle analysis, commonly called a well-to-wheels (WTW) analysis. This WTW study analyzes energy use and emissions associated with fuel production (or well-to-tank [WTT]) activities and energy use and emissions associated with vehicle operation (or tank-to-wheels [TTW]) activities.

  20. Review of an energy and exergy analysis of a fuel cell system

    NASA Astrophysics Data System (ADS)

    van den Oosterkamp, P. F.; Goorse, A. A.; Blomen, L. J. M. J.

    A review of an energy and exergy analysis of the KTI 25 kW fuel cell system is described. This system consists of a fuel cell and a fuel processor. An examination of the system's integration concept is done with the aim of pinpointing the existing losses. The exergy calculations are performed with the Aspen Plus programme using a Fortran extension. Energy and energy calculations are presented in a Sankey and Grassmann diagram, respectively. The system's major energy losses are involved with off-gases, while the system's major exergy losses are associated with internal process irreversibilities. It is concluded that the exergy calculations pinpoint the losses accurately and that the exergy analysis gives a better insight of the system's process.

  1. Accurate analysis of electron transfer from quantum dots to metal oxides in quantum dot sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Javad Fahimi, Mohammad; Fathi, Davood; Ansari-Rad, Mehdi

    2015-09-01

    Electron transfer rate from quantum dot (QD) to metal oxide (MO) in quantum dot sensitized solar cells (QDSSCs) has an important role in the efficiency. In this work, we analyse the electron transfer rate from CdSe, CdS and CdTe QDs to TiO2, ZnO and SnO2 MOs by extending the related equations with considering various effects, based on the Marcus theory. In this regard, the effects of QD diameter, QD-MO spacing, the crystalline defects, temperature, and the reorganizational energy, on the electron transfer rate are investigated. The results show that, the maximum electron transfer rate is achieved for CdTe QD with the mentioned three MOs. Moreover, in order to direct the designer to reach the appropriate QDs-MOs combinations for obtaining the maximum electron transfer rate, the average electron transfer rate for various combinations is calculated. For the verification of simulation method, a part of work has been compared with the previous experimental and theoretical results, which indicates the correctness of our simulation algorithm.

  2. Full-dimensional quantum calculations of vibrational levels of NH4+ and isotopomers on an accurate ab initio potential energy surface

    DOE PAGES

    Hua -Gen Yu; Han, Huixian; Guo, Hua

    2016-03-29

    Vibrational energy levels of the ammonium cation (NH4+) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4+ and ND4+ exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. As a result, the low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm–1.

  3. Sensitive and accurate identification of protein–DNA binding events in ChIP-chip assays using higher order derivative analysis

    PubMed Central

    Barrett, Christian L.; Cho, Byung-Kwan

    2011-01-01

    Immuno-precipitation of protein–DNA complexes followed by microarray hybridization is a powerful and cost-effective technology for discovering protein–DNA binding events at the genome scale. It is still an unresolved challenge to comprehensively, accurately and sensitively extract binding event information from the produced data. We have developed a novel strategy composed of an information-preserving signal-smoothing procedure, higher order derivative analysis and application of the principle of maximum entropy to address this challenge. Importantly, our method does not require any input parameters to be specified by the user. Using genome-scale binding data of two Escherichia coli global transcription regulators for which a relatively large number of experimentally supported sites are known, we show that ∼90% of known sites were resolved to within four probes, or ∼88 bp. Over half of the sites were resolved to within two probes, or ∼38 bp. Furthermore, we demonstrate that our strategy delivers significant quantitative and qualitative performance gains over available methods. Such accurate and sensitive binding site resolution has important consequences for accurately reconstructing transcriptional regulatory networks, for motif discovery, for furthering our understanding of local and non-local factors in protein–DNA interactions and for extending the usefulness horizon of the ChIP-chip platform. PMID:21051353

  4. Suitable Reference Genes for Accurate Gene Expression Analysis in Parsley (Petroselinum crispum) for Abiotic Stresses and Hormone Stimuli

    PubMed Central

    Li, Meng-Yao; Song, Xiong; Wang, Feng; Xiong, Ai-Sheng

    2016-01-01

    Parsley, one of the most important vegetables in the Apiaceae family, is widely used in the food, medicinal, and cosmetic industries. Recent studies on parsley mainly focus on its chemical composition, and further research involving the analysis of the plant's gene functions and expressions is required. qPCR is a powerful method for detecting very low quantities of target transcript levels and is widely used to study gene expression. To ensure the accuracy of results, a suitable reference gene is necessary for expression normalization. In this study, four software, namely geNorm, NormFinder, BestKeeper, and RefFinder were used to evaluate the expression stabilities of eight candidate reference genes of parsley (GAPDH, ACTIN, eIF-4α, SAND, UBC, TIP41, EF-1α, and TUB) under various conditions, including abiotic stresses (heat, cold, salt, and drought) and hormone stimuli treatments (GA, SA, MeJA, and ABA). Results showed that EF-1α and TUB were the most stable genes for abiotic stresses, whereas EF-1α, GAPDH, and TUB were the top three choices for hormone stimuli treatments. Moreover, EF-1α and TUB were the most stable reference genes among all tested samples, and UBC was the least stable one. Expression analysis of PcDREB1 and PcDREB2 further verified that the selected stable reference genes were suitable for gene expression normalization. This study can guide the selection of suitable reference genes in gene expression in parsley. PMID:27746803

  5. Suitable Reference Genes for Accurate Gene Expression Analysis in Parsley (Petroselinum crispum) for Abiotic Stresses and Hormone Stimuli.

    PubMed

    Li, Meng-Yao; Song, Xiong; Wang, Feng; Xiong, Ai-Sheng

    2016-01-01

    Parsley, one of the most important vegetables in the Apiaceae family, is widely used in the food, medicinal, and cosmetic industries. Recent studies on parsley mainly focus on its chemical composition, and further research involving the analysis of the plant's gene functions and expressions is required. qPCR is a powerful method for detecting very low quantities of target transcript levels and is widely used to study gene expression. To ensure the accuracy of results, a suitable reference gene is necessary for expression normalization. In this study, four software, namely geNorm, NormFinder, BestKeeper, and RefFinder were used to evaluate the expression stabilities of eight candidate reference genes of parsley (GAPDH, ACTIN, eIF-4α, SAND, UBC, TIP41, EF-1α, and TUB) under various conditions, including abiotic stresses (heat, cold, salt, and drought) and hormone stimuli treatments (GA, SA, MeJA, and ABA). Results showed that EF-1α and TUB were the most stable genes for abiotic stresses, whereas EF-1α, GAPDH, and TUB were the top three choices for hormone stimuli treatments. Moreover, EF-1α and TUB were the most stable reference genes among all tested samples, and UBC was the least stable one. Expression analysis of PcDREB1 and PcDREB2 further verified that the selected stable reference genes were suitable for gene expression normalization. This study can guide the selection of suitable reference genes in gene expression in parsley.

  6. International Atomic Energy Agency intercomparison of ion beam analysis software

    NASA Astrophysics Data System (ADS)

    Barradas, N. P.; Arstila, K.; Battistig, G.; Bianconi, M.; Dytlewski, N.; Jeynes, C.; Kótai, E.; Lulli, G.; Mayer, M.; Rauhala, E.; Szilágyi, E.; Thompson, M.

    2007-09-01

    Ion beam analysis (IBA) includes a group of techniques for the determination of elemental concentration depth profiles of thin film materials. Often the final results rely on simulations, fits and calculations, made by dedicated codes written for specific techniques. Here we evaluate numerical codes dedicated to the analysis of Rutherford backscattering spectrometry, non-Rutherford elastic backscattering spectrometry, elastic recoil detection analysis and non-resonant nuclear reaction analysis data. Several software packages have been presented and made available to the community. New codes regularly appear, and old codes continue to be used and occasionally updated and expanded. However, those codes have to date not been validated, or even compared to each other. Consequently, IBA practitioners use codes whose validity, correctness and accuracy have never been validated beyond the authors' efforts. In this work, we present the results of an IBA software intercomparison exercise, where seven different packages participated. These were DEPTH, GISA, DataFurnace (NDF), RBX, RUMP, SIMNRA (all analytical codes) and MCERD (a Monte Carlo code). In a first step, a series of simulations were defined, testing different capabilities of the codes, for fixed conditions. In a second step, a set of real experimental data were analysed. The main conclusion is that the codes perform well within the limits of their design, and that the largest differences in the results obtained are due to differences in the fundamental databases used (stopping power and scattering cross section). In particular, spectra can be calculated including Rutherford cross sections with screening, energy resolution convolutions including energy straggling, and pileup effects, with agreement between the codes available at the 0.1% level. This same agreement is also available for the non-RBS techniques. This agreement is not limited to calculation of spectra from particular structures with predetermined

  7. Compact, accurate description of diagnostic neutral beam propagation and attenuation in a high temperature plasma for charge exchange recombination spectroscopy analysis.

    PubMed

    Bespamyatnov, Igor O; Rowan, William L; Granetz, Robert S

    2008-10-01

    Charge exchange recombination spectroscopy on Alcator C-Mod relies on the use of the diagnostic neutral beam injector as a source of neutral particles which penetrate deep into the plasma. It employs the emission resulting from the interaction of the beam atoms with fully ionized impurity ions. To interpret the emission from a given point in the plasma as the density of emitting impurity ions, the density of beam atoms must be known. Here, an analysis of beam propagation is described which yields the beam density profile throughout the beam trajectory from the neutral beam injector to the core of the plasma. The analysis includes the effects of beam formation, attenuation in the neutral gas surrounding the plasma, and attenuation in the plasma. In the course of this work, a numerical simulation and an analytical approximation for beam divergence are developed. The description is made sufficiently compact to yield accurate results in a time consistent with between-shot analysis.

  8. Accurate measurement of muscle belly length in the motion analysis laboratory: potential for the assessment of contracture.

    PubMed

    Fry, N R; Childs, C R; Eve, L C; Gough, M; Robinson, R O; Shortland, A P

    2003-04-01

    Two-dimensional ultrasound imaging was combined with motion analysis technology to measure distances between remote anatomical landmarks. The length of the belly of the medial gastrocnemius muscle in five normal adults (nine limbs) was estimated using this technique. Our results in vivo were similar to the reported data for the lengths of muscles in cadavers, and were consistent with the expected relationship between muscle belly length and ankle joint angle. Experiments in vitro demonstrated that the accuracy of the device was better than 2 mm over 20 cm. Measurements on the same subject on different occasions showed that the results were repeatable in vivo. Rendering of the reconstructed volume of a foam phantom gave results comparable to photographic images. This validated technique could be used to measure muscle lengths in children with spastic cerebral palsy and indicate which muscles had fixed shortening, and to what extent.

  9. Accurate extraction of Lagrangian coherent structures over finite domains with application to flight data analysis over Hong Kong International Airport

    NASA Astrophysics Data System (ADS)

    Tang, Wenbo; Chan, Pak Wai; Haller, George

    2010-03-01

    Locating Lagrangian coherent structures (LCS) for dynamical systems defined on a spatially limited domain present a challenge because trajectory integration must be stopped at the boundary for lack of further velocity data. This effectively turns the domain boundary into an attractor, introduces edge effects resulting in spurious ridges in the associated finite-time Lyapunov exponent (FTLE) field, and causes some of the real ridges of the FTLE field to be suppressed by strong spurious ridges. To address these issues, we develop a finite-domain FTLE method that renders LCS with an accuracy and fidelity that is suitable for automated feature detection. We show the application of this technique to the analysis of velocity data from aircraft landing at the Hong Kong International Airport.

  10. An accurate potential energy surface for the F + H{sub 2} → HF + H reaction by the coupled-cluster method

    SciTech Connect

    Chen, Jun; Sun, Zhigang E-mail: zhangdh@dicp.ac.cn; Zhang, Dong H. E-mail: zhangdh@dicp.ac.cn

    2015-01-14

    A three dimensional potential energy surface for the F + H{sub 2} → HF + H reaction has been computed by the spin unrestricted coupled cluster method with singles, doubles, triples, and perturbative quadruples [UCCSDT(2){sub Q}] using the augmented correlation-consistent polarised valence quadruple zeta basis set for the fluorine atom and the correlation-consistent polarised valence quadruple zeta basis set for the hydrogen atom. All the calculations are based on the restricted open-shell Hartree-Fock orbitals, together with the frozen core approximations, and the UCCSD(T)/complete basis set (CBS) correction term was included. The global potential energy surface was calculated by fitting the sampled ab initio points without any scaling factor for the correlation energy part using a neutral network function method. Extensive dynamics calculations have been carried out on the potential energy surface. The reaction rate constants, integral cross sections, product rotational states distribution, and forward and backward scattering as a function of collision energy of the F + HD → HF + D, F + HD → DF + H, and F + H{sub 2} reaction, were calculated by the time-independent quantum dynamics scattering theory using the new surface. The satisfactory agreement with the reported experimental observations previously demonstrates the accuracy of the new potential energy surface.

  11. Accurate discrimination of Alzheimer's disease from other dementia and/or normal subjects using SPECT specific volume analysis

    NASA Astrophysics Data System (ADS)

    Iyatomi, Hitoshi; Hashimoto, Jun; Yoshii, Fumuhito; Kazama, Toshiki; Kawada, Shuichi; Imai, Yutaka

    2014-03-01

    Discrimination between Alzheimer's disease and other dementia is clinically significant, however it is often difficult. In this study, we developed classification models among Alzheimer's disease (AD), other dementia (OD) and/or normal subjects (NC) using patient factors and indices obtained by brain perfusion SPECT. SPECT is commonly used to assess cerebral blood flow (CBF) and allows the evaluation of the severity of hypoperfusion by introducing statistical parametric mapping (SPM). We investigated a total of 150 cases (50 cases each for AD, OD, and NC) from Tokai University Hospital, Japan. In each case, we obtained a total of 127 candidate parameters from: (A) 2 patient factors (age and sex), (B) 12 CBF parameters and 113 SPM parameters including (C) 3 from specific volume analysis (SVA), and (D) 110 from voxel-based analysis stereotactic extraction estimation (vbSEE). We built linear classifiers with a statistical stepwise feature selection and evaluated the performance with the leave-one-out cross validation strategy. Our classifiers achieved very high classification performances with reasonable number of selected parameters. In the most significant discrimination in clinical, namely those of AD from OD, our classifier achieved both sensitivity (SE) and specificity (SP) of 96%. In a similar way, our classifiers achieved a SE of 90% and a SP of 98% in AD from NC, as well as a SE of 88% and a SP of 86% in AD from OD and NC cases. Introducing SPM indices such as SVA and vbSEE, classification performances improved around 7-15%. We confirmed that these SPM factors are quite important for diagnosing Alzheimer's disease.

  12. Purification of pharmaceutical preparations using thin-layer chromatography to obtain mass spectra with Direct Analysis in Real Time and accurate mass spectrometry.

    PubMed

    Wood, Jessica L; Steiner, Robert R

    2011-06-01

    Forensic analysis of pharmaceutical preparations requires a comparative analysis with a standard of the suspected drug in order to identify the active ingredient. Purchasing analytical standards can be expensive or unattainable from the drug manufacturers. Direct Analysis in Real Time (DART™) is a novel, ambient ionization technique, typically coupled with a JEOL AccuTOF™ (accurate mass) mass spectrometer. While a fast and easy technique to perform, a drawback of using DART™ is the lack of component separation of mixtures prior to ionization. Various in-house pharmaceutical preparations were purified using thin-layer chromatography (TLC) and mass spectra were subsequently obtained using the AccuTOF™- DART™ technique. Utilizing TLC prior to sample introduction provides a simple, low-cost solution to acquiring mass spectra of the purified preparation. Each spectrum was compared against an in-house molecular formula list to confirm the accurate mass elemental compositions. Spectra of purified ingredients of known pharmaceuticals were added to an in-house library for use as comparators for casework samples. Resolving isomers from one another can be accomplished using collision-induced dissociation after ionization. Challenges arose when the pharmaceutical preparation required an optimized TLC solvent to achieve proper separation and purity of the standard. Purified spectra were obtained for 91 preparations and included in an in-house drug standard library. Primary standards would only need to be purchased when pharmaceutical preparations not previously encountered are submitted for comparative analysis. TLC prior to DART™ analysis demonstrates a time efficient and cost saving technique for the forensic drug analysis community. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Analysis of Federal incentives used to stimulate energy production

    SciTech Connect

    Cone, B.W.; Brenchley, D.L.; Brix, V.L.

    1980-02-01

    Solar energy's share in the national energy budget has caused policy makers to speculate on the reasons for the large difference between present and potential use. Complex technical, economic, legal, institutional, and political interrelationships appear and an attempt is made to present an understanding of that relationship and to enhance the design of solar energy policy. Federal incentives that have been previously used on other energy sources are examined and the report identifies, quantifies, and analyzes such incentives and relates them to current thought about solar energy. The chapters presented are: A Theoretical Approach to Analyzing Incentives for Energy Production; Generic Analysis of Energy Incentives; Nuclear Energy Incentives; Hydroenergy Incentives; Coal Energy Incentives; Oil Energy Incentives; Natural Gas Energy Incentives; and Electricity. Conclusions with respect to solar energy policy for each of these are summed. (MCW)

  14. Combination of micro-dialysis and infrared spectroscopy: a multianalyte assay for accurate biofluid analysis and patient monitoring

    NASA Astrophysics Data System (ADS)

    Vahlsing, Thorsten; Delbeck, Sven; Budde, Janpeter; Ihrig, Dieter; Heise, H. Michael

    2016-03-01

    Micro-dialysis can be used for continuously harvesting body fluids, while a multi-component analysis of the dialysates by infrared spectrometry offers splendid opportunities for monitoring substrates and metabolites such as glucose, lactate and others small enough to penetrate the semi-permeable dialysis membranes. However, a drawback of this process are variable recovery rates, which can be observed especially for subcutaneously implanted catheters in human subjects. Isotonic perfusates were investigated with acetate and mannitol as recovery markers for the dialysis of human serum at 37°C to mimic in vivo patient monitoring. The latter non-ionic substance has been suggested for application when other ionic substances such as bicarbonate or pH are also to be determined. Simultaneously for acetate and mannitol, the depletion of the marker substances from the perfusates using different micro-dialysis devices was investigated under various flow-rates. Relationships between relative dialysate marker concentrations and glucose recovery rates were determined based on multivariate calibrations. For quantification, classical least squares with reference spectra for modelling the serum dialysates was used, rendering a basis for reliable blood glucose and lactate measurements.

  15. Energy engineering analysis program, Anniston Army Depot. Final report

    SciTech Connect

    1984-12-01

    This report presents the results of the Energy Engineering Analysis Program (EEAP) study (Increment F) conducted at the Anniston Army Depot, Anniston, Alabama by Science Applications, Incorporated (SAl) under Contract No. DACAOl-83-C-0099. The report includes an analysis of energy conservation projects that can be accomplished using various Army funds, Post funds, and new management procedures. Also found in the report is a complete listing of recently implemented energy conservation projects, recommended similar future projects and a presentation of current and projected Post energy usage. The result of this analysis indicates that current energy use (FY 1983) can be reduced by 23 percent if these recommendations are adopted.

  16. Realizing a Clean Energy Future: Highlights of NREL Analysis (Brochure)

    SciTech Connect

    Not Available

    2013-12-01

    Profound energy system transformation is underway. In Hawaiian mythology, Maui set out to lasso the sun in order to capture its energy. He succeeded. That may have been the most dramatic leap forward in clean energy systems that the world has known. Until now. Today, another profound transformation is underway. A combination of forces is taking us from a carbon-centric, inefficient energy system to one that draws from diverse energy sources - including the sun. NREL analysis is helping guide energy systems policy and investment decisions through this transformation. This brochure highlights NREL analysis accomplishments in the context of four thematic storylines.

  17. Early Design Energy Analysis Using Building Information Modeling Technology

    DTIC Science & Technology

    2011-11-01

    for building energy use are derived from several key Federal policy instruments. Key Federal laws and statutes that govern building energy use include...energy analysis The first step of energy modeling is to develop an energy model at the ma- cro level. It includes exploring different building shapes...own, how to export the necessary gbXML file, and how to use Green Building Studio™. Re- ports of their experience are due to CERL within a couple of

  18. A Simple Engineering Analysis of Solar Particle Event High Energy Tails and Their Impact on Vehicle Design

    NASA Technical Reports Server (NTRS)

    Singleterry, Robert C., Jr.; Walker, Steven A.; Clowdsley, Martha S.

    2016-01-01

    The mathematical models for Solar Particle Event (SPE) high energy tails are constructed with several di erent algorithms. Since limited measured data exist above energies around 400 MeV, this paper arbitrarily de nes the high energy tail as any proton with an energy above 400 MeV. In order to better understand the importance of accurately modeling the high energy tail for SPE spectra, the contribution to astronaut whole body e ective dose equivalent of the high energy portions of three di erent SPE models has been evaluated. To ensure completeness of this analysis, simple and complex geometries were used. This analysis showed that the high energy tail of certain SPEs can be relevant to astronaut exposure and hence safety. Therefore, models of high energy tails for SPEs should be well analyzed and based on data if possible.

  19. Analysis of latency performance of bluetooth low energy (BLE) networks.

    PubMed

    Cho, Keuchul; Park, Woojin; Hong, Moonki; Park, Gisu; Cho, Wooseong; Seo, Jihoon; Han, Kijun

    2014-12-23

    Bluetooth Low Energy (BLE) is a short-range wireless communication technology aiming at low-cost and low-power communication. The performance evaluation of classical Bluetooth device discovery have been intensively studied using analytical modeling and simulative methods, but these techniques are not applicable to BLE, since BLE has a fundamental change in the design of the discovery mechanism, including the usage of three advertising channels. Recently, there several works have analyzed the topic of BLE device discovery, but these studies are still far from thorough. It is thus necessary to develop a new, accurate model for the BLE discovery process. In particular, the wide range settings of the parameters introduce lots of potential for BLE devices to customize their discovery performance. This motivates our study of modeling the BLE discovery process and performing intensive simulation. This paper is focused on building an analytical model to investigate the discovery probability, as well as the expected discovery latency, which are then validated via extensive experiments. Our analysis considers both continuous and discontinuous scanning modes. We analyze the sensitivity of these performance metrics to parameter settings to quantitatively examine to what extent parameters influence the performance metric of the discovery processes.

  20. Value-Driven Design and Sensitivity Analysis of Hybrid Energy Systems using Surrogate Modeling

    SciTech Connect

    Wenbo Du; Humberto E. Garcia; William R. Binder; Christiaan J. J. Paredis

    2001-10-01

    A surrogate modeling and analysis methodology is applied to study dynamic hybrid energy systems (HES). The effect of battery size on the smoothing of variability in renewable energy generation is investigated. Global sensitivity indices calculated using surrogate models show the relative sensitivity of system variability to dynamic properties of key components. A value maximization approach is used to consider the tradeoff between system variability and required battery size. Results are found to be highly sensitive to the renewable power profile considered, demonstrating the importance of accurate renewable resource modeling and prediction. The documented computational framework and preliminary results represent an important step towards a comprehensive methodology for HES evaluation, design, and optimization.

  1. Building Analysis for Urban Energy Planning Using Key Indicators on Virtual 3d City Models - the Energy Atlas of Berlin

    NASA Astrophysics Data System (ADS)

    Krüger, A.; Kolbe, T. H.

    2012-07-01

    In the context of increasing greenhouse gas emission and global demographic change with the simultaneous trend to urbanization, it is a big challenge for cities around the world to perform modifications in energy supply chain and building characteristics resulting in reduced energy consumption and carbon dioxide mitigation. Sound knowledge of energy resource demand and supply including its spatial distribution within urban areas is of great importance for planning strategies addressing greater energy efficiency. The understanding of the city as a complex energy system affects several areas of the urban living, e.g. energy supply, urban texture, human lifestyle, and climate protection. With the growing availability of 3D city models around the world based on the standard language and format CityGML, energy system modelling, analysis and simulation can be incorporated into these models. Both domains will profit from that interaction by bringing together official and accurate building models including building geometries, semantics and locations forming a realistic image of the urban structure with systemic energy simulation models. A holistic view on the impacts of energy planning scenarios can be modelled and analyzed including side effects on urban texture and human lifestyle. This paper focuses on the identification, classification, and integration of energy-related key indicators of buildings and neighbourhoods within 3D building models. Consequent application of 3D city models conforming to CityGML serves the purpose of deriving indicators for this topic. These will be set into the context of urban energy planning within the Energy Atlas Berlin. The generation of indicator objects covering the indicator values and related processing information will be presented on the sample scenario estimation of heating energy consumption in buildings and neighbourhoods. In their entirety the key indicators will form an adequate image of the local energy situation for

  2. SWOT analysis of the renewable energy sources in Romania - case study: solar energy

    NASA Astrophysics Data System (ADS)

    Lupu, A. G.; Dumencu, A.; Atanasiu, M. V.; Panaite, C. E.; Dumitrașcu, Gh; Popescu, A.

    2016-08-01

    The evolution of energy sector worldwide triggered intense preoccupation on both finding alternative renewable energy sources and environmental issues. Romania is considered to have technological potential and geographical location suitable to renewable energy usage for electricity generation. But this high potential is not fully exploited in the context of policies and regulations adopted globally, and more specific, European Union (EU) environmental and energy strategies and legislation related to renewable energy sources. This SWOT analysis of solar energy source presents the state of the art, potential and future prospects for development of renewable energy in Romania. The analysis concluded that the development of solar energy sector in Romania depends largely on: viability of legislative framework on renewable energy sources, increased subsidies for solar R&D, simplified methodology of green certificates, and educating the public, investors, developers and decision-makers.

  3. Energetic and Ecological Analysis of Energy Saving and Passive Houses

    NASA Astrophysics Data System (ADS)

    Sanytsky, Myroslav; Sekret, Robert; Wojcikiewicz, Mariusz

    2012-06-01

    In this paper results of influence of building-installation system parameters on value of energetic coefficients were calculated. Three types of buildings (standard, energy saving and low energy) with heating surface of 100, 150 i 200 m2 were used. The above types of buildings differ on thermal barrier and heating system efficiency. The influence of the gravity and mechanical ventilation systems on the final heat energy of different kinds of houses was shown. Parameters of the certificate for energy characteristics of building were used. Mathematics models of influence of thermal barrier parameters and heating surface on the value of energy characteristics, namely final energy EF, primary energy EP and useful energy EU were established. Influence of such parameters as heating energy factors, ventilation system and energy sources on the energy efficiency improvement of buildings was analyzed. The building environmental assessment system was proposed on the base of energetic and ecological analysis of houses.

  4. Chemical/hydrogen energy systems analysis

    NASA Astrophysics Data System (ADS)

    Beller, M.

    1982-12-01

    Four hydrogen energy technologies are addressed including: hydrogen recovery from hydrogen separation using hydride technology, photochemical hydrogen production, anode depolarization in electrolytic hydrogen production.

  5. Energy management analysis of lunar oxygen production

    NASA Technical Reports Server (NTRS)

    Fazzolari, R.; Wong-Swanson, B. G.

    1990-01-01

    Energy load models in the process of hydrogen reduction of ilmenite for lunar oxygen production are being developed. The load models will be used as a first step to ultimately determine the optimal energy system needed to supply the power requirements for the process. The goal is to determine the energy requirements in the process of hydrogen reduction of ilmenite to produce oxygen. The general approach is shown, and the objectives are to determine the energy loads of the processes in the system. Subsequent energy management studies will be made to minimize the system losses (irreversibilities) and to design optimal energy system power requirements. A number of processes are being proposed as possible candidates for lunar application and some detailed experimental efforts are being conducted within this project at the University of Arizona. Priorities are directed toward developing the energy models for each of the proposed processes being considered. The immediate goals are to identify the variables that would impact energy requirements and energy sources of supply.

  6. Analysis of energy utilization in spinach processing

    SciTech Connect

    Chhinnan, M.S.; Singh, R.P.; Pedersen, L.D.; Carroad, P.A.; Rose, W.W.; Jacob, N.L.

    1980-03-01

    The equipment and methods used to monitor the electrical and thermal energy consumed in various unit operations in a spinach processing plant are described and the results of a processing plant energy audit are presented. It is concluded that it requires 6.5 MJ of natural gas and fuel oil and 0.072 MJ of electric power to process one kg of new spinach; the energy intensive operations in spinach processing are associated with exhaust boxes, blanchers, and retorts; uniform product flow through the canning line is essential to energy conservation; and design improvements are needed for the blancher, exhaust box, and retort. (LCL)

  7. Accurate and efficient representation of intra­molecular energy in ab initio generation of crystal structures. I. Adaptive local approximate models

    PubMed Central

    Sugden, Isaac; Adjiman, Claire S.; Pantelides, Constantinos C.

    2016-01-01

    The global search stage of crystal structure prediction (CSP) methods requires a fine balance between accuracy and computational cost, particularly for the study of large flexible molecules. A major improvement in the accuracy and cost of the intramolecular energy function used in the CrystalPredictor II [Habgood et al. (2015 ▸). J. Chem. Theory Comput. 11, 1957–1969] program is presented, where the most efficient use of computational effort is ensured via the use of adaptive local approximate model (LAM) placement. The entire search space of the relevant molecule’s conformations is initially evaluated using a coarse, low accuracy grid. Additional LAM points are then placed at appropriate points determined via an automated process, aiming to minimize the computational effort expended in high-energy regions whilst maximizing the accuracy in low-energy regions. As the size, complexity and flexibility of molecules increase, the reduction in computational cost becomes marked. This improvement is illustrated with energy calculations for benzoic acid and the ROY molecule, and a CSP study of molecule (XXVI) from the sixth blind test [Reilly et al. (2016 ▸). Acta Cryst. B72, 439–459], which is challenging due to its size and flexibility. Its known experimental form is successfully predicted as the global minimum. The computational cost of the study is tractable without the need to make unphysical simplifying assumptions. PMID:27910837

  8. A simple but accurate potential for the naphthalene-argon complex: Applications to collisional energy transfer and matrix isolated IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Calvo, F.; Falvo, Cyril; Parneix, Pascal

    2013-01-01

    An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.

  9. A simple but accurate potential for the naphthalene-argon complex: applications to collisional energy transfer and matrix isolated IR spectroscopy.

    PubMed

    Calvo, F; Falvo, Cyril; Parneix, Pascal

    2013-01-21

    An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.

  10. Body Composition Comparison: Bioelectric Impedance Analysis with Dual-Energy X-Ray Absorptiometry in Adult Athletes

    ERIC Educational Resources Information Center

    Company, Joe; Ball, Stephen

    2010-01-01

    The primary purpose of this study was to investigate the accuracy of the DF50 (ImpediMed Ltd, Eight Mile Plains, Queensland, Australia) bioelectrical impedance analysis device using dual-energy x-ray absorptiometry as the criterion in two groups: endurance athletes and power athletes. The secondary purpose was to develop accurate body fat…

  11. Accurate ab initio potential energy curves and spectroscopic properties of the four lowest singlet states of C2

    SciTech Connect

    Boschen, Jeffery S.; Theis, Daniel; Ruedenberg, Klaus; Windus, Theresa L.

    2013-12-07

    The diatomic carbon molecule has a complex electronic structure with a large number of low-lying electronic excited states. In this work, the potential energy curves (PECs) of the four lowest lying singlet states (X-1 Sigma(+)(g), A(1)Pi(u), B-1 Delta(g), and B'(1)Sigma(+)(g)) were obtained by high-level ab initio calculations. Valence electron correlation was accounted for by the correlation energy extrapolation by intrinsic scaling (CEEIS) method. Additional corrections to the PECs included core-valence correlation and relativistic effects. Spin-orbit corrections were found to be insignificant. The impact of using dynamically weighted reference wave functions in conjunction with CEEIS was examined and found to give indistinguishable results from the even weighted method. The PECs showed multiple curve crossings due to the B-1 Delta(g) state as well as an avoided crossing between the two (1)Sigma(+)(g) states. Vibrational energy levels were computed for each of the four electronic states, as well as rotational constants and spectroscopic parameters. Comparison between the theoretical and experimental results showed excellent agreement overall. Equilibrium bond distances are reproduced to within 0.05 %. The dissociation energies of the states agree with experiment to within similar to 0.5 kcal/mol, achieving "chemical accuracy." Vibrational energy levels show average deviations of similar to 20 cm(-1) or less. The B-1 Delta(g) state shows the best agreement with a mean absolute deviation of 2.41 cm(-1). Calculated rotational constants exhibit very good agreement with experiment, as do the spectroscopic constants.

  12. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the F{sup −} + CH{sub 3}F S{sub N}2 and proton-abstraction reactions

    SciTech Connect

    Szabó, István; Telekes, Hajnalka; Czakó, Gábor

    2015-06-28

    We develop a full-dimensional global analytical potential energy surface (PES) for the F{sup −} + CH{sub 3}F reaction by fitting about 50 000 energy points obtained by an explicitly correlated composite method based on the second-order Møller–Plesset perturbation-F12 and coupled-cluster singles, doubles, and perturbative triples-F12a methods and the cc-pVnZ-F12 [n = D, T] basis sets. The PES accurately describes the (a) back-side attack Walden inversion mechanism involving the pre- and post-reaction (b) ion-dipole and (c) hydrogen-bonded complexes, the configuration-retaining (d) front-side attack and (e) double-inversion substitution pathways, as well as (f) the proton-abstraction channel. The benchmark quality relative energies of all the important stationary points are computed using the focal-point analysis (FPA) approach considering electron correlation up to coupled-cluster singles, doubles, triples, and perturbative quadruples method, extrapolation to the complete basis set limit, core-valence correlation, and scalar relativistic effects. The FPA classical(adiabatic) barrier heights of (a), (d), and (e) are −0.45(−0.61), 46.07(45.16), and 29.18(26.07) kcal mol{sup −1}, respectively, the dissociation energies of (b) and (c) are 13.81(13.56) and 13.73(13.52) kcal mol{sup −1}, respectively, and the endothermicity of (f) is 42.54(38.11) kcal mol{sup −1}. Quasiclassical trajectory computations of cross sections, scattering (θ) and initial attack (α) angle distributions, as well as translational and internal energy distributions are performed for the F{sup −} + CH{sub 3}F(v = 0) reaction using the new PES. Apart from low collision energies (E{sub coll}), the S{sub N}2 excitation function is nearly constant, the abstraction cross sections rapidly increase with E{sub coll} from a threshold of ∼40 kcal mol{sup −1}, and retention trajectories via double inversion are found above E{sub coll} = ∼ 30 kcal mol{sup −1}, and at E{sub coll} =

  13. Flexible Framework for Building Energy Analysis: Preprint

    SciTech Connect

    Hale, E.; Macumber, D.; Weaver, E.; Shekhar, D.

    2012-09-01

    In the building energy research and advanced practitioner communities, building models are perturbed across large parameter spaces to assess energy and cost performance in the face of programmatic and economic constraints. This paper describes the OpenStudio software framework for performing such analyses.

  14. Molecular dynamics investigations of ozone on an ab initio potential energy surface with the utilization of pattern-recognition neural network for accurate determination of product formation.

    PubMed

    Le, Hung M; Dinh, Thach S; Le, Hieu V

    2011-10-13

    The singlet-triplet transformation and molecular dissociation of ozone (O(3)) gas is investigated by performing quasi-classical molecular dynamics (MD) simulations on an ab initio potential energy surface (PES) with visible and near-infrared excitations. MP4(SDQ) level of theory with the 6-311g(2d,2p) basis set is executed for three different electronic spin states (singlet, triplet, and quintet). In order to simplify the potential energy function, an approximation is adopted by ignoring the spin-orbit coupling and allowing the molecule to switch favorably and instantaneously to the spin state that is more energetically stable (lowest in energy among the three spin states). This assumption has previously been utilized to study the SiO(2) system as reported by Agrawal et al. (J. Chem. Phys. 2006, 124 (13), 134306). The use of such assumption in this study probably makes the upper limits of computed rate coefficients the true rate coefficients. The global PES for ozone is constructed by fitting 5906 ab initio data points using a 60-neuron two-layer feed-forward neural network. The mean-absolute error and root-mean-squared error of this fit are 0.0446 eV (1.03 kcal/mol) and 0.0756 eV (1.74 kcal/mol), respectively, which reveal very good fitting accuracy. The parameter coefficients of the global PES are reported in this paper. In order to identify the spin state with high confidence, we propose the use of a pattern-recognition neural network, which is trained to predict the spin state of a given configuration (with a prediction accuracy being 95.6% on a set of testing data points). To enhance the prediction effectiveness, a buffer series of five points are validated to confirm the spin state during the MD process to gain better confidence. Quasi-classical MD simulations from 1.2 to 2.4 eV of total internal energy (including zero-point energy) result in rate coefficients of singlet-triplet transformation in the range of 0.027 ps(-1) to 1.21 ps(-1). Also, we find very

  15. How Accurate Are the Minnesota Density Functionals for Noncovalent Interactions, Isomerization Energies, Thermochemistry, and Barrier Heights Involving Molecules Composed of Main-Group Elements?

    PubMed

    Mardirossian, Narbe; Head-Gordon, Martin

    2016-09-13

    The 14 Minnesota density functionals published between the years 2005 and early 2016 are benchmarked on a comprehensive database of 4986 data points (84 data sets) involving molecules composed of main-group elements. The database includes noncovalent interactions, isomerization energies, thermochemistry, and barrier heights, as well as equilibrium bond lengths and equilibrium binding energies of noncovalent dimers. Additionally, the sensitivity of the Minnesota density functionals to the choice of basis set and integration grid is explored for both noncovalent interactions and thermochemistry. Overall, the main strength of the hybrid Minnesota density functionals is that the best ones provide very good performance for thermochemistry (e.g., M06-2X), barrier heights (e.g., M08-HX, M08-SO, MN15), and systems heavily characterized by self-interaction error (e.g., M06-2X, M08-HX, M08-SO, MN15), while the main weakness is that none of them are state-of-the-art for the full spectrum of noncovalent interactions and isomerization energies (although M06-2X is recommended from the 10 hybrid Minnesota functionals). Similarly, the main strength of the local Minnesota density functionals is that the best ones provide very good performance for thermochemistry (e.g., MN15-L), barrier heights (e.g., MN12-L), and systems heavily characterized by self-interaction error (e.g., MN12-L and MN15-L), while the main weakness is that none of them are state-of-the-art for the full spectrum of noncovalent interactions and isomerization energies (although M06-L is clearly the best from the four local Minnesota functionals). As an overall guide, M06-2X and MN15 are perhaps the most broadly useful hybrid Minnesota functionals, while M06-L and MN15-L are perhaps the most broadly useful local Minnesota functionals, although each has different strengths and weaknesses.

  16. Accurate ab initio determination of the adiabatic potential energy function and the Born-Oppenheimer breakdown corrections for the electronic ground state of LiH isotopologues

    NASA Astrophysics Data System (ADS)

    Holka, Filip; Szalay, Péter G.; Fremont, Julien; Rey, Michael; Peterson, Kirk A.; Tyuterev, Vladimir G.

    2011-03-01

    High level ab initio potential energy functions have been constructed for LiH in order to predict vibrational levels up to dissociation. After careful tests of the parameters of the calculation, the final adiabatic potential energy function has been composed from: (a) an ab initio nonrelativistic potential obtained at the multireference configuration interaction with singles and doubles level including a size-extensivity correction and quintuple-sextuple ζ extrapolations of the basis, (b) a mass-velocity-Darwin relativistic correction, and (c) a diagonal Born-Oppenheimer (BO) correction. Finally, nonadiabatic effects have also been considered by including a nonadiabatic correction to the kinetic energy operator of the nuclei. This correction is calculated from nonadiabatic matrix elements between the ground and excited electronic states. The calculated vibrational levels have been compared with those obtained from the experimental data [J. A. Coxon and C. S. Dickinson, J. Chem. Phys. 134, 9378 (2004)]. It was found that the calculated BO potential results in vibrational levels which have root mean square (rms) deviations of about 6-7 cm-1 for LiH and ˜3 cm-1 for LiD. With all the above mentioned corrections accounted for, the rms deviation falls down to ˜1 cm-1. These results represent a drastic improvement over previous theoretical predictions of vibrational levels for all isotopologues of LiH.

  17. Accurate ab initio determination of the adiabatic potential energy function and the Born-Oppenheimer breakdown corrections for the electronic ground state of LiH isotopologues.

    PubMed

    Holka, Filip; Szalay, Péter G; Fremont, Julien; Rey, Michael; Peterson, Kirk A; Tyuterev, Vladimir G

    2011-03-07

    High level ab initio potential energy functions have been constructed for LiH in order to predict vibrational levels up to dissociation. After careful tests of the parameters of the calculation, the final adiabatic potential energy function has been composed from: (a) an ab initio nonrelativistic potential obtained at the multireference configuration interaction with singles and doubles level including a size-extensivity correction and quintuple-sextuple ζ extrapolations of the basis, (b) a mass-velocity-Darwin relativistic correction, and (c) a diagonal Born-Oppenheimer (BO) correction. Finally, nonadiabatic effects have also been considered by including a nonadiabatic correction to the kinetic energy operator of the nuclei. This correction is calculated from nonadiabatic matrix elements between the ground and excited electronic states. The calculated vibrational levels have been compared with those obtained from the experimental data [J. A. Coxon and C. S. Dickinson, J. Chem. Phys. 134, 9378 (2004)]. It was found that the calculated BO potential results in vibrational levels which have root mean square (rms) deviations of about 6-7 cm(-1) for LiH and ∼3 cm(-1) for LiD. With all the above mentioned corrections accounted for, the rms deviation falls down to ∼1 cm(-1). These results represent a drastic improvement over previous theoretical predictions of vibrational levels for all isotopologues of LiH.

  18. Uncertainty analysis of geothermal energy economics

    NASA Astrophysics Data System (ADS)

    Sener, Adil Caner

    This dissertation research endeavors to explore geothermal energy economics by assessing and quantifying the uncertainties associated with the nature of geothermal energy and energy investments overall. The study introduces a stochastic geothermal cost model and a valuation approach for different geothermal power plant development scenarios. The Monte Carlo simulation technique is employed to obtain probability distributions of geothermal energy development costs and project net present values. In the study a stochastic cost model with incorporated dependence structure is defined and compared with the model where random variables are modeled as independent inputs. One of the goals of the study is to attempt to shed light on the long-standing modeling problem of dependence modeling between random input variables. The dependence between random input variables will be modeled by employing the method of copulas. The study focuses on four main types of geothermal power generation technologies and introduces a stochastic levelized cost model for each technology. Moreover, we also compare the levelized costs of natural gas combined cycle and coal-fired power plants with geothermal power plants. The input data used in the model relies on the cost data recently reported by government agencies and non-profit organizations, such as the Department of Energy, National Laboratories, California Energy Commission and Geothermal Energy Association. The second part of the study introduces the stochastic discounted cash flow valuation model for the geothermal technologies analyzed in the first phase. In this phase of the study, the Integrated Planning Model (IPM) software was used to forecast the revenue streams of geothermal assets under different price and regulation scenarios. These results are then combined to create a stochastic revenue forecast of the power plants. The uncertainties in gas prices and environmental regulations will be modeled and their potential impacts will be

  19. Renewable Energy Analysis for Strategic Responsiveness 2 (REASR 2)

    DTIC Science & Technology

    2002-12-01

    The analysis of renewable energy within a hybrid electric generator system for remote military applications has not been studied. This report...added that renewable energy can bring to tactical operation centers and remote power stations (for purposes of homeland security) in terms of increased operational readiness, reduced cost, energy savings and pollution abatement.

  20. Energy Storage Fuel Cell Vehicle Analysis

    SciTech Connect

    Pesaran, A; Markel, T; Zolot, M; Sprik, S; Tataria, H; Duong, T

    2005-08-01

    In recent years, hydrogen fuel cell (FC) vehicle technology has received considerable attention as a strategy to decrease oil consumption and reduce harmful emissions. However, the cost, transient response, and cold performance of FC systems may present significant challenges to widespread adoption of the technology for transportation in the next 15 years. The objectives of this effort were to perform energy storage modeling with fuel cell vehicle simulations to quantify the benefits of hybridization and to identify a process for setting the requirements of ES for hydrogen-powered FC vehicles for U.S. Department of Energy's Energy Storage Program.

  1. Accurate ab initio potential energy surfaces for the 3A'' and 3A' electronic states of the O(3P)+HBr system.

    PubMed

    de Oliveira-Filho, Antonio G S; Ornellas, Fernando R; Peterson, Kirk A

    2012-05-07

    In this work, we report the construction of potential energy surfaces for the (3)A('') and (3)A(') states of the system O((3)P) + HBr. These surfaces are based on extensive ab initio calculations employing the MRCI+Q/CBS+SO level of theory. The complete basis set energies were estimated from extrapolation of MRCI+Q/aug-cc-VnZ(-PP) (n = Q, 5) results and corrections due to spin-orbit effects obtained at the CASSCF/aug-cc-pVTZ(-PP) level of theory. These energies, calculated over a region of the configuration space relevant to the study of the reaction O((3)P) + HBr → OH + Br, were used to generate functions based on the many-body expansion. The three-body potentials were interpolated using the reproducing kernel Hilbert space method. The resulting surface for the (3)A('') electronic state contains van der Waals minima on the entrance and exit channels and a transition state 6.55 kcal/mol higher than the reactants. This barrier height was then scaled to reproduce the value of 5.01 kcal/mol, which was estimated from coupled cluster benchmark calculations performed to include high-order and core-valence correlation, as well as scalar relativistic effects. The (3)A(') surface was also scaled, based on the fact that in the collinear saddle point geometry these two electronic states are degenerate. The vibrationally adiabatic barrier heights are 3.44 kcal/mol for the (3)A('') and 4.16 kcal/mol for the (3)A(') state.

  2. Net energy analysis - powerful tool for selecting elective power options

    SciTech Connect

    Baron, S.

    1995-12-01

    A number of net energy analysis studies have been conducted in recent years for electric power production from coal, oil and uranium fuels; synthetic fuels from coal and oil shale; and heat and electric power from solar energy. This technique is an excellent indicator of investment costs, environmental impact and potential economic competitiveness of alternative electric power systems for energy planners from the Eastern European countries considering future options. Energy conservation is also important to energy planners and the net energy analysis technique is an excellent accounting system on the extent of energy resource conservation. The author proposes to discuss the technique and to present the results of his studies and others in the field. The information supplied to the attendees will serve as a powerful tool to the energy planners considering their electric power options in the future.

  3. Energy flow: image correspondence approximation for motion analysis

    NASA Astrophysics Data System (ADS)

    Wang, Liangliang; Li, Ruifeng; Fang, Yajun

    2016-04-01

    We propose a correspondence approximation approach between temporally adjacent frames for motion analysis. First, energy map is established to represent image spatial features on multiple scales using Gaussian convolution. On this basis, energy flow at each layer is estimated using Gauss-Seidel iteration according to the energy invariance constraint. More specifically, at the core of energy invariance constraint is "energy conservation law" assuming that the spatial energy distribution of an image does not change significantly with time. Finally, energy flow field at different layers is reconstructed by considering different smoothness degrees. Due to the multiresolution origin and energy-based implementation, our algorithm is able to quickly address correspondence searching issues in spite of background noise or illumination variation. We apply our correspondence approximation method to motion analysis, and experimental results demonstrate its applicability.

  4. Computational methods to calculate accurate activation and reaction energies of 1,3-dipolar cycloadditions of 24 1,3-dipoles.

    PubMed

    Lan, Yu; Zou, Lufeng; Cao, Yang; Houk, K N

    2011-12-01

    Theoretical calculations were performed on the 1,3-dipolar cycloaddition reactions of 24 1,3-dipoles with ethylene and acetylene. The 24 1,3-dipoles are of the formula X≡Y(+)-Z(-) (where X is HC or N, Y is N, and Z is CH(2), NH, or O) or X═Y(+)-Z(-) (where X and Z are CH(2), NH, or O and Y is NH, O, or S). The high-accuracy G3B3 method was employed as the reference. CBS-QB3, CCSD(T)//B3LYP, SCS-MP2//B3LYP, B3LYP, M06-2X, and B97-D methods were benchmarked to assess their accuracies and to determine an accurate method that is practical for large systems. Several basis sets were also evaluated. Compared to the G3B3 method, CBS-QB3 and CCSD(T)/maug-cc-pV(T+d)Z//B3LYP methods give similar results for both activation and reaction enthalpies (mean average deviation, MAD, < 1.5 kcal/mol). SCS-MP2//B3LYP and M06-2X give small errors for the activation enthalpies (MAD < 1.5 kcal/mol), while B3LYP has MAD = 2.3 kcal/mol. SCS-MP2//B3LYP and B3LYP give the reasonable reaction enthalpies (MAD < 5.0 kcal/mol). The B3LYP functional also gives good results for most 1,3-dipoles (MAD = 1.9 kcal/mol for 17 common 1,3-dipoles), but the activation and reaction enthalpies for ozone and sulfur dioxide are difficult to calculate by any of the density functional methods.

  5. Communication: Rate coefficients of the H + CH{sub 4} → H{sub 2} + CH{sub 3} reaction from ring polymer molecular dynamics on a highly accurate potential energy surface

    SciTech Connect

    Meng, Qingyong Chen, Jun Zhang, Dong H.

    2015-09-14

    The ring polymer molecular dynamics (RPMD) calculations are performed to calculate rate constants for the title reaction on the recently constructed potential energy surface based on permutation invariant polynomial (PIP) neural-network (NN) fitting [J. Li et al., J. Chem. Phys. 142, 204302 (2015)]. By inspecting convergence, 16 beads are used in computing free-energy barriers at 300 K ≤ T ≤ 1000 K, while different numbers of beads are used for transmission coefficients. The present RPMD rates are in excellent agreement with quantum rates computed on the same potential energy surface, as well as with the experimental measurements, demonstrating further that the RPMD is capable of producing accurate rates for polyatomic chemical reactions even at rather low temperatures.

  6. Fully Coriolis-coupled quantum studies of the H + O2 (upsilon i = 0-2, j i = 0,1) --> OH + O reaction on an accurate potential energy surface: integral cross sections and rate constants.

    PubMed

    Lin, Shi Ying; Sun, Zhigang; Guo, Hua; Zhang, Dong Hui; Honvault, Pascal; Xie, Daiqian; Lee, Soo-Y

    2008-01-31

    We present accurate quantum calculations of the integral cross section and rate constant for the H + O2 --> OH + O combustion reaction on a recently developed ab initio potential energy surface using parallelized time-dependent and Chebyshev wavepacket methods. Partial wave contributions up to J = 70 were computed with full Coriolis coupling, which enabled us to obtain the initial state-specified integral cross sections up to 2.0 eV of the collision energy and thermal rate constants up to 3000 K. The integral cross sections show a large reaction threshold due to the quantum endothermicity of the reaction, and they monotonically increase with the collision energy. As a result, the temperature dependence of the rate constant is of the Arrhenius type. In addition, it was found that reactivity is enhanced by reactant vibrational excitation. The calculated thermal rate constant shows a significant improvement over that obtained on the DMBE IV potential, but it still underestimates the experimental consensus.

  7. Analysis of metabolic energy utilization in the Skylab astronauts

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1977-01-01

    Skylab biomedical data regarding man's metabolic processes for extended periods of weightlessness is presented. The data was used in an integrated metabolic balance analysis which included analysis of Skylab water balance, electrolyte balance, evaporative water loss, and body composition. A theoretical analysis of energy utilization in man is presented. The results of the analysis are presented in tabular and graphic format.

  8. Southeast Regional Clean Energy Policy Analysis

    SciTech Connect

    McLaren, Joyce

    2011-04-01

    More than half of the electricity produced in the southeastern states is fuelled by coal. Although the region produces some coal, most of the states depend heavily on coal imports. Many of the region's aging coal power facilities are planned for retirement within the next 20 years. However, estimates indicate that a 20% increase in capacity is needed over that time to meet the rapidly growing demand. The most common incentives for energy efficiency in the Southeast are loans and rebates; however, total public spending on energy efficiency is limited. The most common state-level policies to support renewable energy development are personal and corporate tax incentives and loans. The region produced 1.8% of the electricity from renewable resources other than conventional hydroelectricity in 2009, half of the national average. There is significant potential for development of a biomass market in the region, as well as use of local wind, solar, methane-to-energy, small hydro, and combined heat and power resources. Options are offered for expanding and strengthening state-level policies such as decoupling, integrated resource planning, building codes, net metering, and interconnection standards to support further clean energy development. Benefits would include energy security, job creation, insurance against price fluctuations, increased value of marginal lands, and local and global environmental paybacks.

  9. Southeast Regional Clean Energy Policy Analysis (Revised)

    SciTech Connect

    McLaren, J.

    2011-04-01

    More than half of the electricity produced in the southeastern states is fuelled by coal. Although the region produces some coal, most of the states depend heavily on coal imports. Many of the region's aging coal power facilities are planned for retirement within the next 20 years. However, estimates indicate that a 20% increase in capacity is needed over that time to meet the rapidly growing demand. The most common incentives for energy efficiency in the Southeast are loans and rebates; however, total public spending on energy efficiency is limited. The most common state-level policies to support renewable energy development are personal and corporate tax incentives and loans. The region produced 1.8% of the electricity from renewable resources other than conventional hydroelectricity in 2009, half of the national average. There is significant potential for development of a biomass market in the region, as well as use of local wind, solar, methane-to-energy, small hydro, and combined heat and power resources. Options are offered for expanding and strengthening state-level policies such as decoupling, integrated resource planning, building codes, net metering, and interconnection standards to support further clean energy development. Benefits would include energy security, job creation, insurance against price fluctuations, increased value of marginal lands, and local and global environmental paybacks.

  10. A Framework for the Comparative Assessment of Neuronal Spike Sorting Algorithms towards More Accurate Off-Line and On-Line Microelectrode Arrays Data Analysis.

    PubMed

    Regalia, Giulia; Coelli, Stefania; Biffi, Emilia; Ferrigno, Giancarlo; Pedrocchi, Alessandra

    2016-01-01

    Neuronal spike sorting algorithms are designed to retrieve neuronal network activity on a single-cell level from extracellular multiunit recordings with Microelectrode Arrays (MEAs). In typical analysis of MEA data, one spike sorting algorithm is applied indiscriminately to all electrode signals. However, this approach neglects the dependency of algorithms' performances on the neuronal signals properties at each channel, which require data-centric methods. Moreover, sorting is commonly performed off-line, which is time and memory consuming and prevents researchers from having an immediate glance at ongoing experiments. The aim of this work is to provide a versatile framework to support the evaluation and comparison of different spike classification algorithms suitable for both off-line and on-line analysis. We incorporated different spike sorting "building blocks" into a Matlab-based software, including 4 feature extraction methods, 3 feature clustering methods, and 1 template matching classifier. The framework was validated by applying different algorithms on simulated and real signals from neuronal cultures coupled to MEAs. Moreover, the system has been proven effective in running on-line analysis on a standard desktop computer, after the selection of the most suitable sorting methods. This work provides a useful and versatile instrument for a supported comparison of different options for spike sorting towards more accurate off-line and on-line MEA data analysis.

  11. Energy, entropy, and economic analysis: some new directions

    SciTech Connect

    Huettner, D.A.

    1981-04-01

    A review of the literature on economic modeling of exhaustible resources notes the debate over how energy analysis, entropy analysis, and economic analysis are related since they all yield different results. The choice of analysis among decision makers shows them dividing into three camps on the basis of the value they give to particular energy sources, the environment, technological change, and other factors. The solution will be a method which combines a realistic treatment of human activity and sees energy as one of several constraints. Future modeling efforts should continue to explore intergenerational equity under uncertainty as well as efficiency. 31 references, 2 figures. (DCK)

  12. Biomass energy analysis for crop dehydration

    SciTech Connect

    Whittier, J.P.; Haase, S.G.; Quinn, M.W.; Zachritz, W.; Lansford, R.; Swanson, D.

    1995-06-01

    In 1994, an agricultural processing facility began constructing a new spice and herb dehydration facility in southern New Mexico. Because of the considerable energy intensity of the dehydration operation, management of energy costs is of special concern to the facility. Biomass energy conversion offers the potential for firms to reduce annual operating costs-especially firms with access to low-cost resources. Because the selected facility produces a biomass by-product as a result of its dehydration operation, it is appropriate to explore the technical, regulatory, institutional and economic conditions that affect the successful utilization of biomass resources. The facility is characterized as a small-scale installation, relative to other energy users. In this context, small-scale represents less than 100 million Btu per hour of thermal load and less than 1 MWe of electrical load. However, the projected annual energy bill is approximately $1.1 million and represents a significant portion of operational costs for the firm. For this study, the biomass resources in southern New Mexico and western Texas are detailed. Annual supplies of various biomass resources (i.e., wood chips, pecan shells, discarded tires and cotton gin trash) were inventoried. Further, delivered costs are projected for each of the resource forms. A technical assessment for the small-scale gasification and combustion systems is presented.

  13. Finite element analysis of the effect of electrodes placement on accurate resistivity measurement in a diamond anvil cell with van der Pauw technique

    NASA Astrophysics Data System (ADS)

    Wu, Baojia; Huang, Xiaowei; Han, Yonghao; Gao, Chunxiao; Peng, Gang; Liu, Cailong; Wang, Yue; Cui, Xiaoyan; Zou, Guangtian

    2010-05-01

    The van der Pauw technique is widely used to determine resistivity of materials. In diamond anvil cell the compressed sample will make the contact placement change under high pressure. Using finite element analysis, we study the effect of contact placement error induced by pressure on the resistivity measurement accuracy of van der Pauw method. The results show the contact placement has a significant effect on determination accuracy. This method can provide accurate determination of sample resistivity when the spacing b between the contact center and sample periphery is less than D/9 (sample diameter). And the effect of contact placement error on accuracy rapidly increases as the contact location is closing to the sample center. For the same contact placement, the contact size error has a more obvious effect on the semiconductor sample.

  14. On the importance of 3D, geometrically accurate, and subject-specific finite element analysis for evaluation of in-vivo soft tissue loads.

    PubMed

    Moerman, Kevin M; van Vijven, Marc; Solis, Leandro R; van Haaften, Eline E; Loenen, Arjan C Y; Mushahwar, Vivian K; Oomens, Cees W J

    2017-04-01

    Pressure ulcers are a type of local soft tissue injury due to sustained mechanical loading and remain a common issue in patient care. People with spinal cord injury (SCI) are especially at risk of pressure ulcers due to impaired mobility and sensory perception. The development of load improving support structures relies on realistic tissue load evaluation e.g. using finite element analysis (FEA). FEA requires realistic subject-specific mechanical properties and geometries. This study focuses on the effect of geometry. MRI is used for the creation of geometrically accurate models of the human buttock for three able-bodied volunteers and three volunteers with SCI. The effect of geometry on observed internal tissue deformations for each subject is studied by comparing FEA findings for equivalent loading conditions. The large variations found between subjects confirms the importance of subject-specific FEA.

  15. Finite element analysis of the effect of electrodes placement on accurate resistivity measurement in a diamond anvil cell with van der Pauw technique

    SciTech Connect

    Wu Baojia; Huang Xiaowei; Han Yonghao; Gao Chunxiao; Peng Gang; Liu Cailong; Wang Yue; Cui Xiaoyan; Zou Guangtian

    2010-05-15

    The van der Pauw technique is widely used to determine resistivity of materials. In diamond anvil cell the compressed sample will make the contact placement change under high pressure. Using finite element analysis, we study the effect of contact placement error induced by pressure on the resistivity measurement accuracy of van der Pauw method. The results show the contact placement has a significant effect on determination accuracy. This method can provide accurate determination of sample resistivity when the spacing b between the contact center and sample periphery is less than D/9 (sample diameter). And the effect of contact placement error on accuracy rapidly increases as the contact location is closing to the sample center. For the same contact placement, the contact size error has a more obvious effect on the semiconductor sample.

  16. Home Performance with ENERGY STAR: Utility Bill Analysis on Homes Participating in Austin Energy's Program

    SciTech Connect

    Belzer, D.; Mosey, G.; Plympton, P.; Dagher, L.

    2007-07-01

    Home Performance with ENERGY STAR (HPwES) is a jointly managed program of the U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA). This program focuses on improving energy efficiency in existing homes via a whole-house approach to assessing and improving a home's energy performance, and helping to protect the environment. As one of HPwES's local sponsors, Austin Energy's HPwES program offers a complete home energy analysis and a list of recommendations for efficiency improvements, along with cost estimates. To determine the benefits of this program, the National Renewable Energy Laboratory (NREL) collaborated with the Pacific Northwest National Laboratory (PNNL) to conduct a statistical analysis using energy consumption data of HPwES homes provided by Austin Energy. This report provides preliminary estimates of average savings per home from the HPwES Loan Program for the period 1998 through 2006. The results from this preliminary analysis suggest that the HPwES program sponsored by Austin Energy had a very significant impact on reducing average cooling electricity for participating households. Overall, average savings were in the range of 25%-35%, and appear to be robust under various criteria for the number of households included in the analysis.

  17. Analysis of PURPA and solar energy

    SciTech Connect

    Rice, M.

    1980-03-01

    The Public Utility Regulatory Policies Act of 1978 (PURPA) is designed to promote energy conservation, the efficient use of utility resources, and equitable rates. PURPA specifically directs the Federal Energy Regulatory Commission (FERC) to encourage small power production from renewable resources (and also cogeneration of electric energy as well as heat) by setting standards under which facilities qualify for interconnection, and guidelines for sales between utilities and independent facilities. The way FERC carries out this mandate may critically affect the development of solar alternatives to electric power production from fossil and nuclear resources. This report comments on proposed FERC regulations and suggests ways to encourage small power production within the PURPA mandate. In addition, some internal strains within PURPA are analyzed that seem to limit the effectiveness with which FERC can encourage independent facilities, and possible modifications to PURPA are suggested. 255 references.

  18. Guidelines for the analysis of free energy calculations

    NASA Astrophysics Data System (ADS)

    Klimovich, Pavel V.; Shirts, Michael R.; Mobley, David L.

    2015-05-01

    Free energy calculations based on molecular dynamics simulations show considerable promise for applications ranging from drug discovery to prediction of physical properties and structure-function studies. But these calculations are still difficult and tedious to analyze, and best practices for analysis are not well defined or propagated. Essentially, each group analyzing these calculations needs to decide how to conduct the analysis and, usually, develop its own analysis tools. Here, we review and recommend best practices for analysis yielding reliable free energies from molecular simulations. Additionally, we provide a Python tool, http://arxiv.org/abs/alchemical-analysis.py, freely available on GitHub as part of the pymbar package (located at http://github.com/choderalab/pymbar), that implements the analysis practices reviewed here for several reference simulation packages, which can be adapted to handle data from other packages. Both this review and the tool covers analysis of alchemical calculations generally, including free energy estimates via both thermodynamic integration and free energy perturbation-based estimators. Our Python tool also handles output from multiple types of free energy calculations, including expanded ensemble and Hamiltonian replica exchange, as well as standard fixed ensemble calculations. We also survey a range of statistical and graphical ways of assessing the quality of the data and free energy estimates, and provide prototypes of these in our tool. We hope this tool and discussion will serve as a foundation for more standardization of and agreement on best practices for analysis of free energy calculations.

  19. Guidelines for the analysis of free energy calculations.

    PubMed

    Klimovich, Pavel V; Shirts, Michael R; Mobley, David L

    2015-05-01

    Free energy calculations based on molecular dynamics simulations show considerable promise for applications ranging from drug discovery to prediction of physical properties and structure-function studies. But these calculations are still difficult and tedious to analyze, and best practices for analysis are not well defined or propagated. Essentially, each group analyzing these calculations needs to decide how to conduct the analysis and, usually, develop its own analysis tools. Here, we review and recommend best practices for analysis yielding reliable free energies from molecular simulations. Additionally, we provide a Python tool, alchemical-analysis.py, freely available on GitHub as part of the pymbar package (located at http://github.com/choderalab/pymbar), that implements the analysis practices reviewed here for several reference simulation packages, which can be adapted to handle data from other packages. Both this review and the tool covers analysis of alchemical calculations generally, including free energy estimates via both thermodynamic integration and free energy perturbation-based estimators. Our Python tool also handles output from multiple types of free energy calculations, including expanded ensemble and Hamiltonian replica exchange, as well as standard fixed ensemble calculations. We also survey a range of statistical and graphical ways of assessing the quality of the data and free energy estimates, and provide prototypes of these in our tool. We hope this tool and discussion will serve as a foundation for more standardization of and agreement on best practices for analysis of free energy calculations.

  20. Guidelines for the analysis of free energy calculations

    PubMed Central

    Klimovich, Pavel V.; Shirts, Michael R.; Mobley, David L.

    2015-01-01

    Free energy calculations based on molecular dynamics (MD) simulations show considerable promise for applications ranging from drug discovery to prediction of physical properties and structure-function studies. But these calculations are still difficult and tedious to analyze, and best practices for analysis are not well defined or propagated. Essentially, each group analyzing these calculations needs to decide how to conduct the analysis and, usually, develop its own analysis tools. Here, we review and recommend best practices for analysis yielding reliable free energies from molecular simulations. Additionally, we provide a Python tool, alchemical–analysis.py, freely available on GitHub at https://github.com/choderalab/pymbar–examples, that implements the analysis practices reviewed here for several reference simulation packages, which can be adapted to handle data from other packages. Both this review and the tool covers analysis of alchemical calculations generally, including free energy estimates via both thermodynamic integration and free energy perturbation-based estimators. Our Python tool also handles output from multiple types of free energy calculations, including expanded ensemble and Hamiltonian replica exchange, as well as standard fixed ensemble calculations. We also survey a range of statistical and graphical ways of assessing the quality of the data and free energy estimates, and provide prototypes of these in our tool. We hope these tools and discussion will serve as a foundation for more standardization of and agreement on best practices for analysis of free energy calculations. PMID:25808134

  1. Flow injection combined with ICP-MS for accurate high throughput analysis of elemental impurities in pharmaceutical products according to USP <232>/<233>.

    PubMed

    Fischer, Lisa; Zipfel, Barbara; Koellensperger, Gunda; Kovac, Jessica; Bilz, Susanne; Kunkel, Andrea; Venzago, Cornel; Hann, Stephan

    2014-07-01

    New guidelines of the United States Pharmacopeia (USP), European Pharmacopeia (EP) and international organization (ICH, International Conference on Harmonization) regulating elemental impurity limits in pharmaceuticals seal the end of unspecific analysis of metal(oid)s as outlined in USP <231> and EP 2.4.8. Chapter USP <232> and EP 5.20 as well as drafts from ICH Q3D specify both daily doses and concentration limits of metallic impurities in pharmaceutical final products and in active pharmaceutical ingredients (API) and excipients. In chapters USP <233> and EP 2.4.20 method implementation, validation and quality control during the analytical process are described. By contrast with the--by now--applied methods, substance specific quantitative analysis features new basic requirements, further, significantly lower detection limits ask for the necessity of a general changeover of the methodology toward sensitive multi element analysis by ICP-AES and ICP-MS, respectively. A novel methodological approach based on flow injection analysis and ICP-SFMS/ICP-QMS for the quick and accurate analysis of Cd, Pb, As, Hg, Ir, Os, Pd, Pt, Rh, Ru, Cr, Mo, Ni, V, Cu, Mn, Fe and Zn in drug products by prior dilution, dissolution or microwave assisted closed vessel digestion according to the regulations is presented. In comparison to the acquisition of continuous signals, this method is advantageous with respect to the unprecedented high sample throughput due to a total analysis time of approximately 30s and the low sample consumption of below 50 μL, while meeting the strict USP demands on detection/quantification limits, precision and accuracy.

  2. Accurate calculations on 9 Λ-S and 28 Ω states of NSe radical in the gas phase: Potential energy curves, spectroscopic parameters and spin-orbit couplings

    NASA Astrophysics Data System (ADS)

    Shi, Deheng; Li, Peiling; Sun, Jinfeng; Zhu, Zunlue

    2014-01-01

    The potential energy curves (PECs) of 28 Ω states generated from 9 Λ-S states (X2Π, 14Π, 16Π, 12Σ+, 14Σ+, 16Σ+, 14Σ-, 24Π and 14Δ) are studied for the first time using an ab initio quantum chemical method. All the 9 Λ-S states correlate to the first two dissociation limits, N(4Su) + Se(3Pg) and N(4Su) + Se(3Dg), of NSe radical. Of these Λ-S states, the 16Σ+, 14Σ+, 16Π, 24Π and 14Δ are found to be rather weakly bound states. The 12Σ+ is found to be unstable and has double wells. And the 16Σ+, 14Σ+, 14Π and 16Π are found to be the inverted ones with the SO coupling included. The PEC calculations are made by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification. The spin-orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. The convergence of the present calculations is discussed with respect to the basis set and the level of theory. Core-valence correlation corrections are included with a cc-pCVTZ basis set. Scalar relativistic corrections are calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The variation with internuclear separation of spin-orbit coupling constants is discussed in brief for some Λ-S states with one shallow well on each PEC. The spectroscopic parameters of 9 Λ-S and 28 Ω states are determined by fitting the first ten vibrational levels whenever available, which are calculated by solving the rovibrational Schrödinger equation with Numerov's method. The splitting energy in the X2Π Λ-S state is determined to be about 864.92 cm-1, which agrees favorably with the measurements of 891.80 cm-1. Moreover, other spectroscopic parameters of Λ-S and Ω states involved here are also in fair agreement with available measurements. It

  3. Hybrid Steered Molecular Dynamics Approach to Computing Absolute Binding Free Energy of Ligand-Protein Complexes: A Brute Force Approach That Is Fast and Accurate.

    PubMed

    Chen, Liao Y

    2015-04-14

    Computing the free energy of binding a ligand to a protein is a difficult task of essential importance for which purpose various theoretical/computational approaches have been pursued. In this paper, we develop a hybrid steered molecular dynamics (hSMD) method capable of resolving one ligand–protein complex within a few wall-clock days with high enough accuracy to compare with the experimental data. This hSMD approach is based on the relationship between the binding affinity and the potential of mean force (PMF) in the established literature. It involves simultaneously steering n (n = 1, 2, 3, ...) centers of mass of n selected segments of the ligand using n springs of infinite stiffness. Steering the ligand from a single initial state chosen from the bound state ensemble to the corresponding dissociated state, disallowing any fluctuations of the pulling centers along the way, one can determine a 3n-dimensional PMF curve connecting the two states by sampling a small number of forward and reverse pulling paths. This PMF constitutes a large but not the sole contribution to the binding free energy. Two other contributors are (1) the partial partition function containing the equilibrium fluctuations of the ligand at the binding site and the deviation of the initial state from the PMF minimum and (2) the partial partition function containing rotation and fluctuations of the ligand around one of the pulling centers that is fixed at a position far from the protein. We implement this hSMD approach for two ligand–protein complexes whose structures were determined and whose binding affinities were measured experimentally: caprylic acid binding to bovine β-lactoglobulin and glutathione binding to Schistosoma japonicum glutathione S-transferase tyrosine 7 to phenylalanine mutant. Our computed binding affinities agree with the experimental data within a factor of 1.5. The total time of computation for these two all-atom model systems (consisting of 96K and 114K atoms

  4. Renewable Energy and Efficiency Modeling Analysis Partnership (REMAP): An Analysis of How Different Energy Models Addressed a Common High Renewable Energy Penetration Scenario in 2025

    SciTech Connect

    Blair, Nate; Jenkin, Thomas; Milford, James; Short, Walter; Sullivan, Patrick; Evans, David; Lieberman, Elliot; Goldstein, Gary; Wright, Evelyn; Jayaraman, Kamala R.; Venkatesh, Boddu; Kleiman, Gary; Namovicz, Christopher; Smith, Bob; Palmer, Karen; Wiser, Ryan; Wood, Frances

    2009-09-01

    Energy system modeling can be intentionally or unintentionally misused by decision-makers. This report describes how both can be minimized through careful use of models and thorough understanding of their underlying approaches and assumptions. The analysis summarized here assesses the impact that model and data choices have on forecasting energy systems by comparing seven different electric-sector models. This analysis was coordinated by the Renewable Energy and Efficiency Modeling Analysis Partnership (REMAP), a collaboration among governmental, academic, and nongovernmental participants.

  5. Accurate density-functional calculation of core-electron binding energies with a scaled polarized triple-zeta basis set. (III). Extension to open-shell molecules

    NASA Astrophysics Data System (ADS)

    Hu, Ching-Han; Chong, Delano P.

    1997-03-01

    Density functional theory and the unrestricted generalized transition state (uGTS) model were applied to study the core-electron binding energies (CEBEs) of open-shell molecules. Basis set scaling based on Clementi and Raimondi's rules for atomic screening was used along with the cc-pVTZ basis set. The scaled pVTZ basis set is almost as good as the cc-pV5Z and complete basis set limit in predicting CEBEs. For small molecules (O 2, NO, NF 2 and NO 2) the average absolute deviation (aad) of our prediction (scaled pVTZ) is only 0.29 eV. For the larger molecule (CF 3) 2NO the aad is 0.56 eV, compared with experimental uncertainty of 0.5 eV. Theoretical predicted multiplet splittings for the small molecules agree quite well with experiment: the average deviation is -0.33 eV. For (CF 3) 2NO the calculated multiplet splittings are much smaller than the experimental ones. We also predict the CEBEs of PO, SN and SO, which have not been observed experimentally.

  6. How Accurate Can a Local Coupled Cluster Approach Be in Computing the Activation Energies of Late-Transition-Metal-Catalyzed Reactions with Au, Pt, and Ir?

    PubMed

    Kang, Runhua; Lai, Wenzhen; Yao, Jiannian; Shaik, Sason; Chen, Hui

    2012-09-11

    To improve the accuracy of local coupled cluster (LCC) methods in computing activation energies, we propose herein a new computational scheme. Its applications to various types of late-transition-metal-catalyzed reactions involving Au, Pt, and Ir indicate that the new corrective approach for LCC methods can downsize the mean unsigned deviation and maximum deviation, from the CCSD(T)/CBS reference, to about 0.3 and 0.9 kcal/mol. Using this method, we also calibrated the performance of popular density functionals, with respect to the same test set of reactions. It is concluded that the best functional is the general-purpose double hybrid functional B2GP-PLYP. Other well-performing functionals include the "kinetic" functionals M06-2X and BMK, which have a large percentage of HF exchange, and general-purpose functionals like PBE0 and wB97X. Comparatively, general-purpose functionals like PBE0 and TPSSh perform much better than the tested "kinetic" functionals for Pt-/Ir-catalyzed reactions, while the opposite is true for Au-catalyzed reactions. In contrast, wB97X performs more uniformly in these two classes of reactions. These findings hint that even within the scope of late transition metals, different types of reactions may require different types of optimal DFT methods. Empirical dispersion correction of DFT was found to have a small or no effect on the studied reactions barriers.

  7. Local energy governance in vermont: an analysis of energy system transition strategies and actor capacity

    NASA Astrophysics Data System (ADS)

    Rowse, Tarah

    While global, national, and regional efforts to address climate and energy challenges remain essential, local governments and community groups are playing an increasingly stronger and vital role. As an active state in energy system policy, planning and innovation, Vermont offers a testing ground for research into energy governance at the local level. A baseline understanding of the energy planning and energy organizing activities initiated at the local level can support efforts to foster a transition to a sustainable energy system in Vermont. Following an inductive, applied and participatory approach, and grounded in the fields of sustainability transitions, energy planning, and community energy, this research project identifies conditions for change, including opportunities and challenges, within Vermont energy system decision-making and governance at the local level. The following questions are posed: What are the main opportunities and challenges for sustainable energy development at the town level? How are towns approaching energy planning? What are the triggers that will facilitate a faster transition to alternative energy systems, energy efficiency initiatives, and localized approaches? In an effort to answer these questions two studies were conducted: 1) an analysis of municipal energy plans, and 2) a survey of local energy actors. Study 1 examined Vermont energy planning at the state and local level through a review and comparison of 40 municipal plan energy chapters with the state 2011 Comprehensive Energy Plan. On average, municipal plans mentioned just over half of the 24 high-level strategies identified in the Comprehensive Energy Plan. Areas of strong and weak agreement were examined. Increased state and regional interaction with municipal energy planners would support more holistic and coordinated energy planning. The study concludes that while municipalities are keenly aware of the importance of education and partnerships, stronger policy mechanisms

  8. Energy and Energy Cost Savings Analysis of the IECC for Commercial Buildings

    SciTech Connect

    Zhang, Jian; Athalye, Rahul A.; Hart, Philip R.; Rosenberg, Michael I.; Xie, YuLong; Goel, Supriya; Mendon, Vrushali V.; Liu, Bing

    2013-08-30

    The purpose of this analysis is to assess the relative energy and energy cost performance of commercial buildings designed to meet the requirements found in the commercial energy efficiency provisions of the International Energy Conservation Code (IECC). Section 304(b) of the Energy Conservation and Production Act (ECPA), as amended, requires the Secretary of Energy to make a determination each time a revised version of ASHRAE Standard 90.1 is published with respect to whether the revised standard would improve energy efficiency in commercial buildings. As many states have historically adopted the IECC for both residential and commercial buildings, PNNL has evaluated the impacts of the commercial provisions of the 2006, 2009, and 2012 editions of the IECC. PNNL also compared energy performance with corresponding editions of ANSI/ASHRAE/IES Standard 90.1 to help states and local jurisdictions make informed decisions regarding model code adoption.

  9. Ultra-high-performance liquid chromatography electrospray ionization tandem mass spectrometry for accurate analysis of glycerophospholipids and sphingolipids in drug resistance tumor cells.

    PubMed

    Li, Lin; Wang, Linlin; Shangguan, Dihua; Wei, Yanbo; Han, Juanjuan; Xiong, Shaoxiang; Zhao, Zhenwen

    2015-02-13

    Glycerophospholipids and sphingolipids are important signaling molecules which are involved in many physiological and pathological processes. Here we reported an effective method for accurate analysis of these lipids by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The methanol method was adopted for extraction of lipids due to its simplicity and high efficiency. It was found that two subclasses of sphingolipids, sulfatide (ST) and cerebroside (CB), were heat labile, so a decreased temperature in the ion source of MS might be necessary for these compounds analysis. In addition, it was found that the isobaric interferences were commonly existent, for example, the m/z of 16:0/18:1 PC containing two (13)C isotope being identical to that of 16:0/18:0 PC determined by a unit mass resolution mass spectrometer; therefore, a baseline separation of interferential species was required to maintain selectivity and accuracy of analysis. In this work, an ultra-high-performance liquid chromatography (UHPLC)-based method was developed for separation of interferential species. Moreover, in order to deal with the characteristics of different polarity and wide dynamic range of glycerophospholipids and sphingolipids in biological systems, three detecting conditions were combined together for comprehensive and rational analysis of glycerophospholipids and sphingolipids. The method was utilized to profile glycerophospholipids and sphingolipids in drug resistant tumor cells. Our results showed that many lipids were significantly changed in drug resistant tumor cells compared to paired drug sensitive tumor cells. This is a systematic report about the isobaric interferences and heat labile compounds interferences when analyzing glycerophospholipids and sphingolipids by ESI-MS/MS, which aids in ruling out one potential source of systematic error to ensure the accuracy of analysis.

  10. Proceedings of the 1991 Socioeconomic Energy Research and Analysis Conference

    SciTech Connect

    Not Available

    1993-07-01

    These proceedings analyze US energy policy as it pertains to minority groups. Example topics include: Economic impacts of the National Energy Strategy on minority and majority households, Utility measures to assist payment-troubled customers, Equity impacts of controlling energy usage through market-based versus regulatory approaches, Technical and planning support for the DOE-HUD initiative for energy efficiency in housing, an analysis of residential energy consumption and expenditures by minority households by home type and housing vintage, and methodical issues in evaluating integrated least cost planning programs.

  11. Optical analysis of solar energy tubular absorbers.

    PubMed

    Saltiel, C; Sokolov, M

    1982-11-15

    The energy absorbed by a solar energy tubular receiver element for a single incident ray is derived. Two types of receiver elements were analyzed: (1) an inner tube with an absorbing coating surrounded by a semitransparent cover tube, and (2) a semitransparent inner tube filled with an absorbing fluid surrounded by a semitransparent cover tube. The formation of ray cascades in the semitransparent tubes is considered. A numerical simulation to investigate the influence of the angle of incidence, sizing, thickness, and coefficient of extinction of the tubes was performed. A comparison was made between receiver elements with and without cover tubes. Ray tracing analyses in which rays were followed within the tubular receiver element as well as throughout the rest of the collector were performed for parabolic and circular trough concentrating collectors.

  12. Regional analysis of energy facility siting

    SciTech Connect

    Lipfert, F W; Meier, P M; Kleinman, L I

    1980-01-01

    This paper has examined some of the regional environmental parameters of energy facility siting, with emphasis on air quality impacts. An example of a siting optimization study was presented, and it was shown how difficult it presently is to specify an environmental objective function that is universally applicable. The importance of regional background effects was discussed, and long-range transport models were used to analyze the relative importance of local and long-range impacts.

  13. Local Energy Monitoring and Control Analysis

    DTIC Science & Technology

    1980-08-28

    reducing total operating cost and enabling the system to run more efficiently and thus use less energy. (j) Enthalpy Control Through the use, when...efficient, of outside air instead of conditioned air a building may be cooled without the use of a mechanical cooling system. (see (a)) (k) Enthalpy ...outdoor and return air DB temperature or can be a more com- ... plex system based on the total heat or enthalpy of the supply air. Single zone single

  14. Neutron energy analysis by silicon prisms

    NASA Astrophysics Data System (ADS)

    Schulz, J.; Ott, F.; Hülsen, Ch.; Krist, Th.

    2013-11-01

    Neutron energy analysing by refraction with prisms allows to measure different wavelengths at the same time thus avoiding losses due to monochromatization. We built and tested a refractive energy analysing device made from small prisms, where losses only occur due to the attenuation in the material. We measured the refraction and the transmission of MgF2 and Si prisms at the V14 reflectometer in Berlin at 4.9 Å to check their applicability. The experimentally determined linear attenuation coefficients are 0.055 cm-1 for the MgF2 and 0.03 cm-1 for the Si prisms. An energy analyser consisting of silicon prism layers was measured at the EROS reflectometer at the LLB in a white neutron beam. The useful wavelength band was 2.4-7.6 Å. At 6.7 Å a wavelength resolution of 5% and a transmission of 53% were achieved. The surface roughness of the prisms could be determined to be (0.011±0.006)deg.

  15. An accurate, flexible and small optical fiber sensor: a novel technological breakthrough for real-time analysis of dynamic blood flow data in vivo.

    PubMed

    Yuan, Qiao-ying; Zhang, Ling; Xiao, Dan; Zhao, Kun; Lin, Chun; Si, Liang-yi

    2014-01-01

    Because of the limitations of existing methods and techniques for directly obtaining real-time blood data, no accurate microflow in vivo real-time analysis method exists. To establish a novel technical platform for real-time in vivo detection and to analyze average blood pressure and other blood flow parameters, a small, accurate, flexible, and nontoxic Fabry-Perot fiber sensor was designed. The carotid sheath was implanted through intubation of the rabbit carotid artery (n = 8), and the blood pressure and other detection data were determined directly through the veins. The fiber detection results were compared with test results obtained using color Doppler ultrasound and a physiological pressure sensor recorder. Pairwise comparisons among the blood pressure results obtained using the three methods indicated that real-time blood pressure information obtained through the fiber sensor technique exhibited better correlation than the data obtained with the other techniques. The highest correlation (correlation coefficient of 0.86) was obtained between the fiber sensor and pressure sensor. The blood pressure values were positively related to the total cholesterol level, low-density lipoprotein level, number of red blood cells, and hemoglobin level, with correlation coefficients of 0.033, 0.129, 0.358, and 0.373, respectively. The blood pressure values had no obvious relationship with the number of white blood cells and high-density lipoprotein and had a negative relationship with triglyceride levels, with a correlation coefficient of -0.031. The average ambulatory blood pressure measured by the fiber sensor exhibited a negative correlation with the quantity of blood platelets (correlation coefficient of -0.839, P<0.05). The novel fiber sensor can thus obtain in vivo blood pressure data accurately, stably, and in real time; the sensor can also determine the content and status of the blood flow to some extent. Therefore, the fiber sensor can obtain partially real

  16. An Accurate, Flexible and Small Optical Fiber Sensor: A Novel Technological Breakthrough for Real-Time Analysis of Dynamic Blood Flow Data In Vivo

    PubMed Central

    Yuan, Qiao-ying; Zhang, Ling; Xiao, Dan; Zhao, Kun; Lin, Chun; Si, Liang-yi

    2014-01-01

    Because of the limitations of existing methods and techniques for directly obtaining real-time blood data, no accurate microflow in vivo real-time analysis method exists. To establish a novel technical platform for real-time in vivo detection and to analyze average blood pressure and other blood flow parameters, a small, accurate, flexible, and nontoxic Fabry-Perot fiber sensor was designed. The carotid sheath was implanted through intubation of the rabbit carotid artery (n = 8), and the blood pressure and other detection data were determined directly through the veins. The fiber detection results were compared with test results obtained using color Doppler ultrasound and a physiological pressure sensor recorder. Pairwise comparisons among the blood pressure results obtained using the three methods indicated that real-time blood pressure information obtained through the fiber sensor technique exhibited better correlation than the data obtained with the other techniques. The highest correlation (correlation coefficient of 0.86) was obtained between the fiber sensor and pressure sensor. The blood pressure values were positively related to the total cholesterol level, low-density lipoprotein level, number of red blood cells, and hemoglobin level, with correlation coefficients of 0.033, 0.129, 0.358, and 0.373, respectively. The blood pressure values had no obvious relationship with the number of white blood cells and high-density lipoprotein and had a negative relationship with triglyceride levels, with a correlation coefficient of –0.031. The average ambulatory blood pressure measured by the fiber sensor exhibited a negative correlation with the quantity of blood platelets (correlation coefficient of −0.839, P<0.05). The novel fiber sensor can thus obtain in vivo blood pressure data accurately, stably, and in real time; the sensor can also determine the content and status of the blood flow to some extent. Therefore, the fiber sensor can obtain partially real

  17. ANALYSIS OF WATER AND ENERGY FLUXES USING SATELLITE, ENERGY BALANCE MODELING AND OBSERVATIONS (Invited)

    NASA Astrophysics Data System (ADS)

    Irmak, A.

    2009-12-01

    Surface energy fluxes, including net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G) are critical in surface energy balance of any terrain or landscapes. Estimation or measurement of these energy fluxes is important for completing the water balance in terrestrial ecosystems, and therefore accurately predicting the effects of global climate and land use change. The objectives of this study were to (1) use METRICtm (Mapping Evapotranspiration at high Resolution using Internalized Calibration) model for estimating land surface energy fluxes in Nebraska (NE) by utilizing satellite remote sensing data, (2) identify model bias in energy balance components compared with measurements from Bowen Ratio Energy Balance System (BREBS) in a subsurface drip-irrigated maize field in South-central Nebraska, and (3) understand the partitioning of available energy into latent heat for corn and soybean cropping systems at large scale. A total of 15 Landsat images were processed to estimate instantaneous surface energy fluxes at Landsat overpasses with METRIC model. Results showed that the model predictions of the surface energy fluxes and daily evapotranspiration were correlated well with the BREBS measurements. There is a need, however, to test the performance of the model with in-situ observations in other locations with different dataset before utilizing it for crucial water regulatory and policy decisions. The METRICtm approach illustrated how an ‘off-the-shelf’ model can be applied operationally over a significant time period and how that model behaves. The findings makes considerable contribution to our understanding of estimating land surface energy fluxes using remote sensing approach and experimentally describes the operational characteristics of METRICtm and presents its limitations.

  18. Isotopic Ratio Outlier Analysis of the S. cerevisiae Metabolome Using Accurate Mass Gas Chromatography/Time-of-Flight Mass Spectrometry: A New Method for Discovery.

    PubMed

    Qiu, Yunping; Moir, Robyn; Willis, Ian; Beecher, Chris; Tsai, Yu-Hsuan; Garrett, Timothy J; Yost, Richard A; Kurland, Irwin J

    2016-03-01

    Isotopic ratio outlier analysis (IROA) is a (13)C metabolomics profiling method that eliminates sample to sample variance, discriminates against noise and artifacts, and improves identification of compounds, previously done with accurate mass liquid chromatography/mass spectrometry (LC/MS). This is the first report using IROA technology in combination with accurate mass gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS), here used to examine the S. cerevisiae metabolome. S. cerevisiae was grown in YNB media, containing randomized 95% (13)C, or 5%(13)C glucose as the single carbon source, in order that the isotopomer pattern of all metabolites would mirror the labeled glucose. When these IROA experiments are combined, the abundance of the heavy isotopologues in the 5%(13)C extracts, or light isotopologues in the 95%(13)C extracts, follows the binomial distribution, showing mirrored peak pairs for the molecular ion. The mass difference between the (12)C monoisotopic and the (13)C monoisotopic equals the number of carbons in the molecules. The IROA-GC/MS protocol developed, using both chemical and electron ionization, extends the information acquired from the isotopic peak patterns for formulas generation. The process that can be formulated as an algorithm, in which the number of carbons, as well as the number of methoximations and silylations are used as search constraints. In electron impact (EI/IROA) spectra, the artifactual peaks are identified and easily removed, which has the potential to generate "clean" EI libraries. The combination of chemical ionization (CI) IROA and EI/IROA affords a metabolite identification procedure that enables the identification of coeluting metabolites, and allowed us to characterize 126 metabolites in the current study.

  19. Prediction of {sup 2}D Rydberg energy levels of {sup 6}Li and {sup 7}Li based on very accurate quantum mechanical calculations performed with explicitly correlated Gaussian functions

    SciTech Connect

    Bubin, Sergiy; Sharkey, Keeper L.; Adamowicz, Ludwik

    2013-04-28

    Very accurate variational nonrelativistic finite-nuclear-mass calculations employing all-electron explicitly correlated Gaussian basis functions are carried out for six Rydberg {sup 2}D states (1s{sup 2}nd, n= 6, Horizontal-Ellipsis , 11) of the {sup 7}Li and {sup 6}Li isotopes. The exponential parameters of the Gaussian functions are optimized using the variational method with the aid of the analytical energy gradient determined with respect to these parameters. The experimental results for the lower states (n= 3, Horizontal-Ellipsis , 6) and the calculated results for the higher states (n= 7, Horizontal-Ellipsis , 11) fitted with quantum-defect-like formulas are used to predict the energies of {sup 2}D 1s{sup 2}nd states for {sup 7}Li and {sup 6}Li with n up to 30.

  20. Exploratory Data Analysis of Acceleration Signals to Select Light-Weight and Accurate Features for Real-Time Activity Recognition on Smartphones

    PubMed Central

    Khan, Adil Mehmood; Siddiqi, Muhammad Hameed; Lee, Seok-Won

    2013-01-01

    Smartphone-based activity recognition (SP-AR) recognizes users' activities using the embedded accelerometer sensor. Only a small number of previous works can be classified as online systems, i.e., the whole process (pre-processing, feature extraction, and classification) is performed on the device. Most of these online systems use either a high sampling rate (SR) or long data-window (DW) to achieve high accuracy, resulting in short battery life or delayed system response, respectively. This paper introduces a real-time/online SP-AR system that solves this problem. Exploratory data analysis was performed on acceleration signals of 6 activities, collected from 30 subjects, to show that these signals are generated by an autoregressive (AR) process, and an accurate AR-model in this case can be built using a low SR (20 Hz) and a small DW (3 s). The high within class variance resulting from placing the phone at different positions was reduced using kernel discriminant analysis to achieve position-independent recognition. Neural networks were used as classifiers. Unlike previous works, true subject-independent evaluation was performed, where 10 new subjects evaluated the system at their homes for 1 week. The results show that our features outperformed three commonly used features by 40% in terms of accuracy for the given SR and DW. PMID:24084108

  1. Rapid and Accurate Analysis of an X-Ray Fluorescence Microscopy Data Set through Gaussian Mixture-Based Soft Clustering Methods

    PubMed Central

    Ward, Jesse; Marvin, Rebecca; O'Halloran, Thomas; Jacobsen, Chris; Vogt, Stefan

    2013-01-01

    X-ray fluorescence (XRF) microscopy is an important tool for studying trace metals in biology, enabling simultaneous detection of multiple elements of interest and allowing quantification of metals in organelles without the need for subcellular fractionation. Currently, analysis of XRF images is often done using manually defined regions of interest (ROIs). However, since advances in synchrotron instrumentation have enabled the collection of very large data sets encompassing hundreds of cells, manual approaches are becoming increasingly impractical. We describe here the use of soft clustering to identify cell ROIs based on elemental contents, using data collected over a sample of the malaria parasite Plasmodium falciparum as a test case. Soft clustering was able to successfully classify regions in infected erythrocytes as “parasite,”“food vacuole,”“host,” or “background.” In contrast, hard clustering using the k-means algorithm was found to have difficulty in distinguishing cells from background. While initial tests showed convergence on two or three distinct solutions in 60% of the cells studied, subsequent modifications to the clustering routine improved results to yield 100% consistency in image segmentation. Data extracted using soft cluster ROIs were found to be as accurate as data extracted using manually defined ROIs, and analysis time was considerably improved. PMID:23924688

  2. Economic analysis of waste-to-energy industry in China.

    PubMed

    Zhao, Xin-Gang; Jiang, Gui-Wu; Li, Ang; Wang, Ling

    2016-02-01

    The generation of municipal solid waste is further increasing in China with urbanization and improvement of living standards. The "12th five-year plan" period (2011-2015) promotes waste-to-energy technologies for the harmless disposal and recycling of municipal solid waste. Waste-to-energy plant plays an important role for reaching China's energy conservation and emission reduction targets. Industrial policies and market prospect of waste-to-energy industry are described. Technology, cost and benefit of waste-to-energy plant are also discussed. Based on an economic analysis of a waste-to-energy project in China (Return on Investment, Net Present Value, Internal Rate of Return, and Sensitivity Analysis) the paper makes the conclusions.

  3. Asymmetric-Structure Analysis of Carbon and Energy Markets

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Cao, Guangxi

    2016-02-01

    This study aimed to investigate the asymmetric structure between the carbon and energy markets from two aspects of different trends (up or down) and volatility-transmission direction using asymmetric detrended cross-correlation analysis (DCCA) cross-correlation coefficient test, multifractal asymmetric DCCA (MF-ADCCA) method, asymmetric volatility-constrained correlation metric and time rate of information-flow approach. We sampled 1283 observations from January 2008 to December 2012 among pairs of carbon and energy markets for analysis. Empirical results show that the (1) asymmetric characteristic from the cross-correlation between carbon and returns in the energy markets is significant, (2) asymmetric cross-correlation between carbon and energy market price returns is persistent and multifractral and (3) volatility of the base assets of energy market returns is more influential to the base asset of the carbon market than that of the energy market.

  4. Dual-energy x-ray image decomposition by independent component analysis

    NASA Astrophysics Data System (ADS)

    Jiang, Yifeng; Jiang, Dazong; Zhang, Feng; Zhang, Dengfu; Lin, Gang

    2001-09-01

    The spatial distributions of bone and soft tissue in human body are separated by independent component analysis (ICA) of dual-energy x-ray images. It is because of the dual energy imaging modelí-s conformity to the ICA model that we can apply this method: (1) the absorption in body is mainly caused by photoelectric absorption and Compton scattering; (2) they take place simultaneously but are mutually independent; and (3) for monochromatic x-ray sources the total attenuation is achieved by linear combination of these two absorption. Compared with the conventional method, the proposed one needs no priori information about the accurate x-ray energy magnitude for imaging, while the results of the separation agree well with the conventional one.

  5. Elk Valley Rancheria Energy Efficiency and Alternatives Analysis

    SciTech Connect

    Ed Wait, Elk Valley Rancheria; Frank Ziano & Associates, Inc.

    2011-11-30

    Elk Valley Rancheria; Tribe; renewable energy; energy options analysis. The Elk Valley Rancheria, California ('Tribe') is a federally recognized Indian tribe located in Del Norte County, California, in the northwestern corner of California. The Tribe, its members and Tribal enterprises are challenged by increasing energy costs and undeveloped local energy resources. The Tribe currently lacks an energy program. The Tribal government lacked sufficient information to make informed decisions about potential renewable energy resources, energy alternatives and other energy management issues. To meet this challenge efficiently, the Tribe contracted with Frank Zaino and Associates, Inc. to help become more energy self-sufficient, by reducing their energy costs and promoting energy alternatives that stimulate economic development. Frank Zaino & Associates, Inc. provided a high level economic screening analysis based on anticipated electric and natural gas rates. This was in an effort to determine which alternative energy system will performed at a higher level so the Tribe could reduce their energy model by 30% from alternative fuel sources. The feasibility study will identify suitable energy alternatives and conservation methods that will benefit the Tribe and tribal community through important reductions in cost. The lessons learned from these conservation efforts will yield knowledge that will serve a wider goal of executing energy efficiency measures and practices in Tribal residences and business facilities. Pacific Power is the provider of electrical power to the four properties under review at $ 0.08 per Kilowatt-hour (KWH). This is a very low energy cost compared to alternative energy sources. The Tribe used baseline audits to assess current and historic energy usage at four Rancheria owned facilities. Past electric and gas billing statements were retained for review for the four buildings that will be audited. A comparative assessment of the various energy usages

  6. Understanding Community Wind Energy Development in Oregon: An Integrated Analysis

    NASA Astrophysics Data System (ADS)

    Yin, Yao

    This research intends to provide insights into community wind energy development in Oregon using an integrated analysis approach, which incorporates GIS Suitability Analysis, Socio-Political Analysis, and Empirical Case Studies. In the GIS analysis, we developed a model through a series of steps (including data acquisition, preprocessing, data management, manipulation and analysis, and output generation) to measure how suitable a location is for developing wind energy in Oregon. The socio-political analysis adopts the Socio-Political Evaluation of Energy Deployment (SPEED) framework and categorized policies and incentives that are applicable to community wind projects into three classes: strategic, tactical, and operational. The empirical case studies, focused on seven projects in Oregon, are analyzed using the actor-network theoretical framework, and their opportunities and barriers are explored as well.

  7. High-throughput image analysis of tumor spheroids: a user-friendly software application to measure the size of spheroids automatically and accurately.

    PubMed

    Chen, Wenjin; Wong, Chung; Vosburgh, Evan; Levine, Arnold J; Foran, David J; Xu, Eugenia Y

    2014-07-08

    The increasing number of applications of three-dimensional (3D) tumor spheroids as an in vitro model for drug discovery requires their adaptation to large-scale screening formats in every step of a drug screen, including large-scale image analysis. Currently there is no ready-to-use and free image analysis software to meet this large-scale format. Most existing methods involve manually drawing the length and width of the imaged 3D spheroids, which is a tedious and time-consuming process. This study presents a high-throughput image analysis software application - SpheroidSizer, which measures the major and minor axial length of the imaged 3D tumor spheroids automatically and accurately; calculates the volume of each individual 3D tumor spheroid; then outputs the results in two different forms in spreadsheets for easy manipulations in the subsequent data analysis. The main advantage of this software is its powerful image analysis application that is adapted for large numbers of images. It provides high-throughput computation and quality-control workflow. The estimated time to process 1,000 images is about 15 min on a minimally configured laptop, or around 1 min on a multi-core performance workstation. The graphical user interface (GUI) is also designed for easy quality control, and users can manually override the computer results. The key method used in this software is adapted from the active contour algorithm, also known as Snakes, which is especially suitable for images with uneven illumination and noisy background that often plagues automated imaging processing in high-throughput screens. The complimentary "Manual Initialize" and "Hand Draw" tools provide the flexibility to SpheroidSizer in dealing with various types of spheroids and diverse quality images. This high-throughput image analysis software remarkably reduces labor and speeds up the analysis process. Implementing this software is beneficial for 3D tumor spheroids to become a routine in vitro model

  8. Analysis of Remote Site Energy Storage and Generation Systems

    DTIC Science & Technology

    1979-07-01

    alternate energy sources for remote site applications. The first phase of the effort centered on the broad based study of hydrogen storage, thermal storage...divided into two phases, the first phase was a generalized study and analysis of potential remote site alternate energy and energy storage systems. The...systems consisted of the following seven steps. First , the power system output requirements were established based on the work statement requirements

  9. Comparative analysis of net energy balance for satellite power systems (SPS) and other energy systems

    SciTech Connect

    Cirillo, R.R.; Cho, B.S.; Monarch, M.R.; Levine, E.P.

    1980-04-01

    The net energy balance of seven electric energy systems is assessed: two coal-based, one nuclear, two terrestrial solar, and two solar power satellites, with principal emphasis on the latter two systems. Solar energy systems require much less operating energy per unit of electrical output. However, on the basis of the analysis used here, coal and nuclear systems are two to five times more efficient at extracting useful energy from the primary resource base than are the solar energy systems. The payback period for all systems is less than 1.5 years, except for the terrestrial photovoltaic (19.8 yr) and the solar power satellite system (6.4 yr), both of which rely on energy-intensive silicon cells.

  10. Identification of Energy Efficiency Opportunities through Building Data Analysis and Achieving Energy Savings through Improved Controls

    SciTech Connect

    Katipamula, Srinivas; Taasevigen, Danny J.; Koran, Bill

    2014-09-04

    This chapter will highlight analysis techniques to identify energy efficiency opportunities to improve operations and controls. A free tool, Energy Charting and Metrics (ECAM), will be used to assist in the analysis of whole-building, sub-metered, and/or data from the building automation system (BAS). Appendix A describes the features of ECAM in more depth, and also provide instructions for downloading ECAM and all resources pertaining to using ECAM.

  11. Feasibility study for a novel method of dual energy x-ray analysis

    NASA Astrophysics Data System (ADS)

    Midgley, S. M.

    2011-09-01

    Dual energy x-ray analysis (DEXA) is investigated using a nonlinear model for the x-ray linear attenuation coefficient μ that is expressed as a function of electron density Ne and the fourth compositional ratio R4. Nonlinear simultaneous equations are solved using a least-squares algorithm based upon the method of Levenberg and Marquardt. Measurements of μ for low atomic number materials (containing elements hydrogen to calcium) at energies 32-66 keV are used to study DEXA accuracy as a function of sample composition, photon energy and their separation ΔE. Results are presented for ΔE = 5-30 keV, for 2% measurement precision, and the doses involved are quantified. The model is subject to propagation of error analysis and results are presented for the relationship between measurement uncertainties and those for Ne and R4. The analysis shows how DEXA accuracy is controlled by the fractional compositional cross-product, which represents the contribution of composition to μ, and how this can be optimized by careful selection of beam energies according to the compositional range of interest. Accurate DEXA is achieved over restricted energy and compositional ranges: soft tissues only at approximately 15-25 keV, all tissues at approximately 30-80 keV and, for situations where a higher dose can be tolerated, all tissues at approximately 4-8 MeV.

  12. Applications analysis of high energy lasers

    NASA Technical Reports Server (NTRS)

    Arno, R. D.; Mackay, J. S.; Nishioka, K.

    1972-01-01

    An analysis and comparison of laser technology with competing technologies were made to determine possible laser applications. The analysis was undertaken as follows: (1) possible applications were listed and categorized; (2) required components were enumerated and the characteristics of these components were extrapolated; (3) complete system characteristics were calculated parametrically for selected applications using the postulated component characteristics; and (4) where possible and appropriate, comparisons were made with competing systems. It was found that any large scale replacement of existing systems and methods by lasers requires many technological advances in laser and associated systems. However, several applications appear feasible, such as low orbit drag make-up, orbit changing, communications, and illumination applications.

  13. BMEWS Capture and Analysis of Reflected Energy Clear Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BMEWS Capture and Analysis of Reflected Energy - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  14. Analysis of the Russian Market for Building Energy Efficiency

    SciTech Connect

    Lychuk, Taras; Evans, Meredydd; Halverson, Mark A.; Roshchanka, Volha

    2012-12-01

    This report provides analysis of the Russian energy efficiency market for the building sector from the perspective of U.S. businesses interested in exporting relevant technologies, products and experience to Russia. We aim to help U.S. energy efficiency and environmental technologies businesses to better understand the Russian building market to plan their market strategy.

  15. Orienting the Neighborhood: A Subdivision Energy Analysis Tool; Preprint

    SciTech Connect

    Christensen, C.; Horowitz, S.

    2008-07-01

    This paper describes a new computerized Subdivision Energy Analysis Tool being developed to allow users to interactively design subdivision street layouts while receiving feedback about energy impacts based on user-specified building design variants and availability of roof surfaces for photovoltaic and solar water heating systems.

  16. Intuitive Density Functional Theory-Based Energy Decomposition Analysis for Protein-Ligand Interactions.

    PubMed

    Phipps, M J S; Fox, T; Tautermann, C S; Skylaris, C-K

    2017-03-08

    First-principles quantum mechanical calculations with methods such as density functional theory (DFT) allow the accurate calculation of interaction energies between molecules. These interaction energies can be dissected into chemically relevant components such as electrostatics, polarization, and charge transfer using energy decomposition analysis (EDA) approaches. Typically EDA has been used to study interactions between small molecules; however, it has great potential to be applied to large biomolecular assemblies such as protein-protein and protein-ligand interactions. We present an application of EDA calculations to the study of ligands that bind to the thrombin protein, using the ONETEP program for linear-scaling DFT calculations. Our approach goes beyond simply providing the components of the interaction energy; we are also able to provide visual representations of the changes in density that happen as a result of polarization and charge transfer, thus pinpointing the functional groups between the ligand and protein that participate in each kind of interaction. We also demonstrate with this approach that we can focus on studying parts (fragments) of ligands. The method is relatively insensitive to the protocol that is used to prepare the structures, and the results obtained are therefore robust. This is an application to a real protein drug target of a whole new capability where accurate DFT calculations can produce both energetic and visual descriptors of interactions. These descriptors can be used to provide insights for tailoring interactions, as needed for example in drug design.

  17. Analysis of Final Energy Consumption Patterns in 10 Arab Countries

    NASA Astrophysics Data System (ADS)

    Al-Hinti, I.; Al-Ghandoor, A.

    2009-08-01

    This study presents an analysis of the energy consumption patterns in 10 Arab countries: Saudi Arabia, Kuwait, United Arab Emirates (UAE), Syria, Lebanon, Jordan, Egypt, Libya, Tunisia, and Algeria. Commonalities and variations between these countries are discussed and explained through key economic and energy indicators, and the relationship between the overall final energy consumption per capita and the GDP per capita is examined. The distribution of the final energy consumption across different sectors is also analysed, and the patterns of consumption in the industrial, transportation, and residential sectors are discussed with focus on the types of energy consumed, and the main drivers of this consumption. The findings and the conclusions of this study are believed to be beneficial to the national energy policy planners in identifying possible strengths, weaknesses, and areas of emphasis and improvement in their strategic energy plans.

  18. Path Analysis of Household Energy Use - Neighborhood Comparison

    NASA Astrophysics Data System (ADS)

    Tenjin, Nanako

    Many have studied residential energy use in relation with appliance types and efficiency, dwelling types, behavior, socio-demographics, and geography. Yet little is understood about the interrelations among the variables in the context of energy use. We used data collected through residential energy surveys from two neighborhoods in California. Path analysis models with emphasis on the appliance characteristics, appliance usage, and household energy use were developed and statistically tested. Our study showed that even a simple demographic variable like household size has unique effect channels on household energy use and also the channel was significant in one neighborhood but not in the other. While our model leaves much to be improved, the model supports a framework of energy use to explain energy use from a behavioral perspective in which household decisions were related to socio-demographic characteristics but neighborhood difference also plays a major role.

  19. A thermal, thermoelastic, and wear analysis of high-energy disk brakes

    NASA Technical Reports Server (NTRS)

    Kennedy, F. E., Jr.; Wu, J. J.; Ling, F. F.

    1974-01-01

    A thermomechanical investigation of the sliding contact problem encountered in high-energy disk brakes is described. The analysis includes a modelling, using the finite element method of the thermoelastic instabilities that cause transient changes in contact area to occur on the friction surface. In order to include the effect of wear at the contact surface, a wear criterion is proposed that results in the prediction of wear rates for disk brakes that are quite close to experimentally determined wear rates. The thermal analysis shows that the transient temperature distribution in a disk brake assembly can be determined more accurately by use of this thermomechanical analysis than by a more conventional analysis that assumes constant contact conditions. It also shows that lower, more desirable, temperatures in disk brakes can be attained by increasing the volume, the thermal conductivity, and, especially, the heat capacity of the brake components.

  20. Linking Automated Data Analysis and Visualization with Applications in Developmental Biology and High-Energy Physics

    SciTech Connect

    Ruebel, Oliver

    2009-11-20

    acceleration, physicists model LWFAs computationally. The datasets produced by LWFA simulations are (i) extremely large, (ii) of varying spatial and temporal resolution, (iii) heterogeneous, and (iv) high-dimensional, making analysis and knowledge discovery from complex LWFA simulation data a challenging task. To address these challenges this thesis describes the integration of the visualization system VisIt and the state-of-the-art index/query system FastBit, enabling interactive visual exploration of extremely large three-dimensional particle datasets. Researchers are especially interested in beams of high-energy particles formed during the course of a simulation. This thesis describes novel methods for automatic detection and analysis of particle beams enabling a more accurate and efficient data analysis process. By integrating these automated analysis methods with visualization, this research enables more accurate, efficient, and effective analysis of LWFA simulation data than previously possible.

  1. Non-targeted screening for contaminants in paper and board food-contact materials using effect-directed analysis and accurate mass spectrometry.

    PubMed

    Bengtström, Linda; Rosenmai, Anna Kjerstine; Trier, Xenia; Jensen, Lisbeth Krüger; Granby, Kit; Vinggaard, Anne Marie; Driffield, Malcolm; Højslev Petersen, Jens

    2016-06-01

    Due to large knowledge gaps in chemical composition and toxicological data for substances involved, paper and board food-contact materials (P&B FCM) have been emerging as a FCM type of particular concern for consumer safety. This study describes the development of a step-by-step strategy, including extraction, high-performance liquid chromatography (HPLC) fractionation, tentative identification of relevant substances and in vitro testing of selected tentatively identified substances. As a case study, we used two fractions from a recycled pizza box sample which exhibited aryl hydrocarbon receptor (AhR) activity. These fractions were analysed by gas chromatography (GC) and ultra-HPLC (UHPLC) coupled to quadrupole time-of-flight mass spectrometers (QTOF MS) in order tentatively to identify substances. The elemental composition was determined for peaks above a threshold, and compared with entries in a commercial mass spectral library for GC-MS (GC-EI-QTOF MS) analysis and an in-house built library of accurate masses for substances known to be used in P&B packaging for UHPLC-QTOF analysis. Of 75 tentatively identified substances, 15 were initially selected for further testing in vitro; however, only seven were commercially available and subsequently tested in vitro and quantified. Of these seven, the identities of three pigments found in printing inks were confirmed by UHPLC tandem mass spectrometry (QqQ MS/MS). Two pigments had entries in the database, meaning that a material relevant accurate mass database can provide a fast tentative identification. Pure standards of the seven tentatively identified substances were tested in vitro but could not explain a significant proportion of the AhR-response in the extract. Targeted analyses of dioxins and PCBs, both well-known AhR agonists, was performed. However, the dioxins could explain approximately 3% of the activity observed in the pizza box extract indicating that some very AhR active substance(s) still remain to be

  2. Accurate ab initio-based adiabatic global potential energy surface for the 2{sup 2}A″ state of NH{sub 2} by extrapolation to the complete basis set limit

    SciTech Connect

    Li, Y. Q.; Ma, F. C.; Sun, M. T.

    2013-10-21

    A full three-dimensional global potential energy surface is reported first time for the title system, which is important for the photodissociation processes. It is obtained using double many-body expansion theory and an extensive set of accurate ab initio energies extrapolated to the complete basis set limit. Such a work can be recommended for dynamics studies of the N({sup 2}D) + H{sub 2} reaction, a reliable theoretical treatment of the photodissociation dynamics and as building blocks for constructing the double many-body expansion potential energy surface of larger nitrogen/hydrogen containing systems. In turn, a preliminary theoretical study of the reaction N({sup 2}D)+H{sub 2}(X{sup 1}Σ{sub g}{sup +})(ν=0,j=0)→NH(a{sup 1}Δ)+H({sup 2}S) has been carried out with the method of quasi-classical trajectory on the new potential energy surface. Integral cross sections and thermal rate constants have been calculated, providing perhaps the most reliable estimate of the integral cross sections and the rate constants known thus far for such a reaction.

  3. Energy Navigation: Simulation Evaluation and Benefit Analysis

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Oseguera-Lohr, Rosa M.; Lewis, Elliot T.

    2011-01-01

    This paper presents results from two simulation studies investigating the use of advanced flight-deck-based energy navigation (ENAV) and conventional transport-category vertical navigation (VNAV) for conducting a descent through a busy terminal area, using Continuous Descent Arrival (CDA) procedures. This research was part of the Low Noise Flight Procedures (LNFP) element within the Quiet Aircraft Technology (QAT) Project, and the subsequent Airspace Super Density Operations (ASDO) research focus area of the Airspace Project. A piloted simulation study addressed development of flight guidance, and supporting pilot and Air Traffic Control (ATC) procedures for high density terminal operations. The procedures and charts were designed to be easy to understand, and to make it easy for the crew to make changes via the Flight Management Computer Control-Display Unit (FMC-CDU) to accommodate changes from ATC.

  4. Sensitivity Analysis of Offshore Wind Cost of Energy (Poster)

    SciTech Connect

    Dykes, K.; Ning, A.; Graf, P.; Scott, G.; Damiami, R.; Hand, M.; Meadows, R.; Musial, W.; Moriarty, P.; Veers, P.

    2012-10-01

    No matter the source, offshore wind energy plant cost estimates are significantly higher than for land-based projects. For instance, a National Renewable Energy Laboratory (NREL) review on the 2010 cost of wind energy found baseline cost estimates for onshore wind energy systems to be 71 dollars per megawatt-hour ($/MWh), versus 225 $/MWh for offshore systems. There are many ways that innovation can be used to reduce the high costs of offshore wind energy. However, the use of such innovation impacts the cost of energy because of the highly coupled nature of the system. For example, the deployment of multimegawatt turbines can reduce the number of turbines, thereby reducing the operation and maintenance (O&M) costs associated with vessel acquisition and use. On the other hand, larger turbines may require more specialized vessels and infrastructure to perform the same operations, which could result in higher costs. To better understand the full impact of a design decision on offshore wind energy system performance and cost, a system analysis approach is needed. In 2011-2012, NREL began development of a wind energy systems engineering software tool to support offshore wind energy system analysis. The tool combines engineering and cost models to represent an entire offshore wind energy plant and to perform system cost sensitivity analysis and optimization. Initial results were collected by applying the tool to conduct a sensitivity analysis on a baseline offshore wind energy system using 5-MW and 6-MW NREL reference turbines. Results included information on rotor diameter, hub height, power rating, and maximum allowable tip speeds.

  5. Accurate Finite Difference Algorithms

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    1996-01-01

    Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

  6. Accurate monotone cubic interpolation

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1991-01-01

    Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.

  7. Differential label-free quantitative proteomic analysis of Shewanella oneidensis cultured under aerobic and suboxic conditions by accurate mass and time tag approach.

    PubMed

    Fang, Ruihua; Elias, Dwayne A; Monroe, Matthew E; Shen, Yufeng; McIntosh, Martin; Wang, Pei; Goddard, Carrie D; Callister, Stephen J; Moore, Ronald J; Gorby, Yuri A; Adkins, Joshua N; Fredrickson, Jim K; Lipton, Mary S; Smith, Richard D

    2006-04-01

    We describe the application of LC-MS without the use of stable isotope labeling for differential quantitative proteomic analysis of whole cell lysates of Shewanella oneidensis MR-1 cultured under aerobic and suboxic conditions. LC-MS/MS was used to initially identify peptide sequences, and LC-FTICR was used to confirm these identifications as well as measure relative peptide abundances. 2343 peptides covering 668 proteins were identified with high confidence and quantified. Among these proteins, a subset of 56 changed significantly using statistical approaches such as statistical analysis of microarrays, whereas another subset of 56 that were annotated as performing housekeeping functions remained essentially unchanged in relative abundance. Numerous proteins involved in anaerobic energy metabolism exhibited up to a 10-fold increase in relative abundance when S. oneidensis was transitioned from aerobic to suboxic conditions.

  8. Hawaii Energy Strategy Project 2: Fossil Energy Review. Task IV. Scenario development and analysis

    SciTech Connect

    Yamaguchi, N.D.; Breazeale, K.

    1993-12-01

    The Hawaii Energy Strategy (HES) Program is a seven-project effort led by the State of Hawaii Department of Business, Economic Development & Tourism (DBEDT) to investigate a wide spectrum of Hawaii energy issues. The East-West Center`s Program on Resources: Energy and Minerals, has been assigned HES Project 2, Fossil Energy Review, which focuses on fossil energy use in Hawaii and the greater regional and global markets. HES Project 2 has four parts: Task I (World and Regional Fossil Energy Dynamics) covers petroleum, natural gas, and coal in global and regional contexts, along with a discussion of energy and the environment. Task II (Fossil Energy in Hawaii) focuses more closely on fossil energy use in Hawaii: current utilization and trends, the structure of imports, possible future sources of supply, fuel substitutability, and energy security. Task III`s emphasis is Greenfield Options; that is, fossil energy sources not yet used in Hawaii. This task is divided into two sections: first, an in-depth {open_quotes}Assessment of Coal Technology Options and Implications for the State of Hawaii,{close_quotes} along with a spreadsheet analysis model, which was subcontracted to the Environmental Assessment and Information Sciences Division of Argonne National Laboratory; and second, a chapter on liquefied natural gas (LNG) in the Asia-Pacific market and the issues surrounding possible introduction of LNG into the Hawaii market.

  9. A fast and accurate method for controlling the correct labeling of products containing buffalo meat using High Resolution Melting (HRM) analysis.

    PubMed

    Sakaridis, Ioannis; Ganopoulos, Ioannis; Argiriou, Anagnostis; Tsaftaris, Athanasios

    2013-05-01

    The substitution of high priced meat with low cost ones and the fraudulent labeling of meat products make the identification and traceability of meat species and their processed products in the food chain important. A polymerase chain reaction followed by a High Resolution Melting (HRM) analysis was developed for species specific detection of buffalo; it was applied in six commercial meat products. A pair of specific 12S and universal 18S rRNA primers were employed and yielded DNA fragments of 220bp and 77bp, respectively. All tested products were found to contain buffalo meat and presented melting curves with at least two visible inflection points derived from the amplicons of the 12S specific and 18S universal primers. The presence of buffalo meat in meat products and the adulteration of buffalo products with unknown species were established down to a level of 0.1%. HRM was proven to be a fast and accurate technique for authentication testing of meat products.

  10. Robust Algorithm for Alignment of Liquid Chromatography-Mass Spectrometry Analyses in an Accurate Mass and Time Tag Data Analysis Pipeline

    SciTech Connect

    Jaitly, Navdeep; Monroe, Matthew E.; Petyuk, Vladislav A.; Clauss, Therese RW; Adkins, Joshua N.; Smith, Richard D.

    2006-11-01

    Liquid chromatography coupled to mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) has become a standard technique for analyzing complex peptide mixtures to determine composition and relative quantity. Several high-throughput proteomics techniques attempt to combine complementary results from multiple LC-MS and LC-MS/MS analyses to provide more comprehensive and accurate results. To effectively collate results from these techniques, variations in mass and elution time measurements between related analyses are corrected by using algorithms designed to align the various types of results: LC-MS/MS vs. LC-MS/MS, LC-MS vs. LC-MS/MS, and LC-MS vs. LC-MS. Described herein are new algorithms referred to collectively as Liquid Chromatography based Mass Spectrometric Warping and Alignment of Retention times of Peptides (LCMSWARP) which use a dynamic elution time warping approach similar to traditional algorithms that correct variation in elution time using piecewise linear functions. LCMSWARP is compared to a linear alignment algorithm that assumes a linear transformation of elution time between analyses. LCMSWARP also corrects for drift in mass measurement accuracies that are often seen in an LC-MS analysis due to factors such as analyzer drift. We also describe the alignment of LC-MS results and provide examples of alignment of analyses from different chromatographic systems to demonstrate more complex transformation functions.

  11. Multi-Locus Variable Number of Tandem Repeat Analysis for Rapid and Accurate Typing of Virulent Multidrug Resistant Escherichia coli Clones

    PubMed Central

    Naseer, Umaer; Olsson-Liljequist, Barbro E.; Woodford, Neil; Dhanji, Hiran; Cantón, Rafael; Sundsfjord, Arnfinn; Lindstedt, Bjørn-Arne

    2012-01-01

    One hundred E. coli isolates from Norway (n = 37), Sweden (n = 24), UK (n = 20) and Spain (n = 19), producing CTX-M-type - (n = 84), or SHV-12 (n = 4) extended spectrum β-lactamases, or the plasmid mediated AmpC, CMY-2 (n = 12), were typed using multi-locus sequence typing (MLST) and multi-locus variable number of tandem repeat analysis (MLVA). Isolates clustered into 33 Sequence Types (STs) and 14 Sequence Type Complexes (STCs), and 58 MLVA-Types (MTs) and 25 different MLVA-Type Complexes (MTCs). A strong agreement between the MLST profile and MLVA typing results was observed, in which all ST131-isolates (n = 39) and most of the STC-648 (n = 10), STC-38 (n = 9), STC-10 (n = 9), STC-405 (n = 8) and STC-23 (n = 6) isolates were clustered distinctly into MTC-29, -36, -20, -14, -10 and -39, respectively. MLVA is a rapid and accurate tool for genotyping isolates of globally disseminated virulent multidrug resistant E. coli lineages, including ST131. PMID:22859970

  12. Identification of fidgety movements and prediction of CP by the use of computer-based video analysis is more accurate when based on two video recordings.

    PubMed

    Adde, Lars; Helbostad, Jorunn; Jensenius, Alexander R; Langaas, Mette; Støen, Ragnhild

    2013-08-01

    This study evaluates the role of postterm age at assessment and the use of one or two video recordings for the detection of fidgety movements (FMs) and prediction of cerebral palsy (CP) using computer vision software. Recordings between 9 and 17 weeks postterm age from 52 preterm and term infants (24 boys, 28 girls; 26 born preterm) were used. Recordings were analyzed using computer vision software. Movement variables, derived from differences between subsequent video frames, were used for quantitative analysis. Sensitivities, specificities, and area under curve were estimated for the first and second recording, or a mean of both. FMs were classified based on the Prechtl approach of general movement assessment. CP status was reported at 2 years. Nine children developed CP of whom all recordings had absent FMs. The mean variability of the centroid of motion (CSD) from two recordings was more accurate than using only one recording, and identified all children who were diagnosed with CP at 2 years. Age at assessment did not influence the detection of FMs or prediction of CP. The accuracy of computer vision techniques in identifying FMs and predicting CP based on two recordings should be confirmed in future studies.

  13. What's the Point of a Raster ? Advantages of 3D Point Cloud Processing over Raster Based Methods for Accurate Geomorphic Analysis of High Resolution Topography.

    NASA Astrophysics Data System (ADS)

    Lague, D.

    2014-12-01

    High Resolution Topographic (HRT) datasets are predominantly stored and analyzed as 2D raster grids of elevations (i.e., Digital Elevation Models). Raster grid processing is common in GIS software and benefits from a large library of fast algorithms dedicated to geometrical analysis, drainage network computation and topographic change measurement. Yet, all instruments or methods currently generating HRT datasets (e.g., ALS, TLS, SFM, stereo satellite imagery) output natively 3D unstructured point clouds that are (i) non-regularly sampled, (ii) incomplete (e.g., submerged parts of river channels are rarely measured), and (iii) include 3D elements (e.g., vegetation, vertical features such as river banks or cliffs) that cannot be accurately described in a DEM. Interpolating the raw point cloud onto a 2D grid generally results in a loss of position accuracy, spatial resolution and in more or less controlled interpolation. Here I demonstrate how studying earth surface topography and processes directly on native 3D point cloud datasets offers several advantages over raster based methods: point cloud methods preserve the accuracy of the original data, can better handle the evaluation of uncertainty associated to topographic change measurements and are more suitable to study vegetation characteristics and steep features of the landscape. In this presentation, I will illustrate and compare Point Cloud based and Raster based workflows with various examples involving ALS, TLS and SFM for the analysis of bank erosion processes in bedrock and alluvial rivers, rockfall statistics (including rockfall volume estimate directly from point clouds) and the interaction of vegetation/hydraulics and sedimentation in salt marshes. These workflows use 2 recently published algorithms for point cloud classification (CANUPO) and point cloud comparison (M3C2) now implemented in the open source software CloudCompare.

  14. A Habermasian Analysis of Local Renewable Energy Deliberations

    ERIC Educational Resources Information Center

    Fast, Stewart

    2013-01-01

    This study pursues a Habermasian analysis of citizen discussions and of the local public sphere to shed light on renewable energy futures in rural east-central Canada. Using data from group discussions, it pursues an investigation of utterances, validity claims and of discourses. The analysis is supplemented by participant observation of publicly…

  15. Clean Energy Policy Analysis: Impact Analysis of Potential Clean Energy Policy Options for the Hawaii Clean Energy Initiative (HCEI)

    SciTech Connect

    Busche, S.; Doris, E.; Braccio, R.; Lippert, D.; Finch, P.; O'Toole, D.; Fetter, J.

    2010-04-01

    This report provides detailed analyses of 21 clean energy policy options considered by the Hawaii Clean Energy Initiative working groups for recommendation to the 2010 Hawaii State Legislature. The report considers the impact each policy may have on ratepayers, businesses, and the state in terms of energy saved, clean energy generated, and the financial costs and benefits. The analyses provide insight into the possible impacts, both qualitative and quantitative, that these policies may have in Hawaii based on the experience with these policies elsewhere. As much as possible, the analyses incorporate Hawaii-specific context to reflect the many unique aspects of energy use in the State of Hawaii.

  16. Analysis of federal incentives used to stimulate energy consumption

    SciTech Connect

    Cole, R.J.; Cone, B.W.; Emery, J.C.; Huelshoff, M.; Lenerz, D.E.; Marcus, A.; Morris, F.A.; Sheppard, W.J.; Sommers, P.

    1981-08-01

    The purpose of the analysis is to identify and quantify Federal incentives that have increased the consumption of coal, oil, natural gas, and electricity. The introductory chapter is intended as a device for presenting the policy questions about the incentives that can be used to stimulate desired levels of energy development. In the theoretical chapter federal incentives were identified for the consumption of energy as Federal government actions whose major intent or result is to stimulate energy consumption. The stimulus comes through changing values of variables included in energy demand functions, thereby inducing energy consumers to move along the function in the direction of greater quantity of energy demanded, or through inducing a shift of the function to a position where more energy will be demanded at a given price. The demand variables fall into one of six categories: price of the energy form, price of complements, price of substitutes, preferences, income, and technology. The government can provide such incentives using six different policy instruments: taxation, disbursements, requirements, nontraditional services, traditional services, and market activity. The four major energy forms were examined. Six energy-consuming sectors were examined: residential, commercial, industrial, agricultural, transportation, and public. Two types of analyses of incentive actions are presented in this volume. The generic chapter focused on actions taken in 1978 across all energy forms. The subsequent chapters traced the patterns of incentive actions, energy form by energy form, from the beginning of the 20th century, to the present. The summary chapter includes the results of the previous chapters presented by energy form, incentive type, and user group. Finally, the implications of these results for solar policy are presented in the last chapter. (MCW)

  17. Benchmarking singlet and triplet excitation energies of molecular semiconductors for singlet fission: Tuning the amount of HF exchange and adjusting local correlation to obtain accurate functionals for singlet-triplet gaps

    NASA Astrophysics Data System (ADS)

    Brückner, Charlotte; Engels, Bernd

    2017-01-01

    Vertical and adiabatic singlet and triplet excitation energies of molecular p-type semiconductors calculated with various DFT functionals and wave-function based approaches are benchmarked against MS-CASPT2/cc-pVTZ reference values. A special focus lies on the singlet-triplet gaps that are very important in the process of singlet fission. Singlet fission has the potential to boost device efficiencies of organic solar cells, but the scope of existing singlet-fission compounds is still limited. A computational prescreening of candidate molecules could enlarge it; yet it requires efficient methods accurately predicting singlet and triplet excitation energies. Different DFT formulations (Tamm-Dancoff approximation, linear response time-dependent DFT, Δ-SCF) and spin scaling schemes along with several ab initio methods (CC2, ADC(2)/MP2, CIS(D), CIS) are evaluated. While wave-function based methods yield rather reliable singlet-triplet gaps, many DFT functionals are shown to systematically underestimate triplet excitation energies. To gain insight, the impact of exact exchange and correlation is in detail addressed.

  18. Energy and Energy Cost Savings Analysis of the 2015 IECC for Commercial Buildings

    SciTech Connect

    Zhang, Jian; Xie, YuLong; Athalye, Rahul A.; Zhuge, Jing Wei; Rosenberg, Michael I.; Hart, Philip R.; Liu, Bing

    2015-09-01

    As required by statute (42 USC 6833), DOE recently issued a determination that ANSI/ASHRAE/IES Standard 90.1-2013 would achieve greater energy efficiency in buildings subject to the code compared to the 2010 edition of the standard. Pacific Northwest National Laboratory (PNNL) conducted an energy savings analysis for Standard 90.1-2013 in support of its determination . While Standard 90.1 is the model energy standard for commercial and multi-family residential buildings over three floors (42 USC 6833), many states have historically adopted the International Energy Conservation Code (IECC) for both residential and commercial buildings. This report provides an assessment as to whether buildings constructed to the commercial energy efficiency provisions of the 2015 IECC would save energy and energy costs as compared to the 2012 IECC. PNNL also compared the energy performance of the 2015 IECC with the corresponding Standard 90.1-2013. The goal of this analysis is to help states and local jurisdictions make informed decisions regarding model code adoption.

  19. Energy and Energy Cost Savings Analysis of the 2015 IECC for Commercial Buildings

    SciTech Connect

    Zhang, Jian; Xie, YuLong; Athalye, Rahul A.; Zhuge, Jing Wei; Rosenberg, Michael I.; Hart, Philip R.; Liu, Bing

    2015-06-01

    As required by statute (42 USC 6833), DOE recently issued a determination that ANSI/ASHRAE/IES Standard 90.1-2013 would achieve greater energy efficiency in buildings subject to the code compared to the 2010 edition of the standard. Pacific Northwest National Laboratory (PNNL) conducted an energy savings analysis for Standard 90.1-2013 in support of its determination . While Standard 90.1 is the model energy standard for commercial and multi-family residential buildings over three floors (42 USC 6833), many states have historically adopted the International Energy Conservation Code (IECC) for both residential and commercial buildings. This report provides an assessment as to whether buildings constructed to the commercial energy efficiency provisions of the 2015 IECC would save energy and energy costs as compared to the 2012 IECC. PNNL also compared the energy performance of the 2015 IECC with the corresponding Standard 90.1-2013. The goal of this analysis is to help states and local jurisdictions make informed decisions regarding model code adoption.

  20. ACMV Energy Analysis for Academic Building: A Case Study

    NASA Astrophysics Data System (ADS)

    Hywel, R.; Tee, B. T.; Arifin, M. Y.; Tan, C. F.; Gan, C. K.; Chong, CT

    2015-09-01

    Building energy audit examines the ways actual energy consumption is currently used in the facility, in the case of a completed and occupied building and identifies some alternatives to reduce current energy usage. Implementation of energy audit are practically used to analyze energy consumption pattern, monitoring on how the energy used varies with time in the building, how the system element interrelate, and study the effect of external environment towards building. In this case study, a preliminary energy audit is focusing on Air-Conditioning & Mechanical Ventilation (ACMV) system which reportedly consumed 40% of the total energy consumption in typical building. It is also the main system that provides comfortable and healthy environment for the occupants. The main purpose of this study is to evaluate the current ACMV system performance, energy optimization and identifying the energy waste on UTeM's academic building. To attain this, the preliminary data is collected and then analyzed. Based on the data, economic analysis will be determined before cost-saving methods are being proposed.

  1. Zero Energy Ready Home Multifamily Case Study Analysis

    SciTech Connect

    Dentz, Jordan; Alaigh, Kunal

    2016-02-05

    Two multifamily buildings planned in Climate Zone 4 were analyzed to determine the cost, energy and performance implications of redesigning them to comply with Zero Energy Ready Home, a recognition program of the U.S. Department of Energy. Energy modeling was conducted on one representative apartment in each building using BEopt. Construction costs were obtained from the developer and subcontractors to determine savings and cost increases over ENERGY STAR. It was found that seven items would be necessary to change to comply with ZERH criteria when starting from the original design which was compliant with ENERGY STAR version 3.0. Design changes were made to the exterior walls, domestic water heating system, duct protection, duct design, garage ventilation, and pest control to comply with ZERH requirements. Energy impacts of upgrading from the original design to ZERH resulted in 2 to 8% reduction in modeled source energy consumption, or 1.7 to 10.4 MMBtu per year, although the original design was already about 8% better than a design configured to minimum ENERGY STAR criteria. According to the BEopt analysis, annualized energy related costs of the ZERH design were slightly higher for the apartment and slightly lower for the townhome when compared to the original design.

  2. Life cycle analysis of energy systems: Methods and experience

    SciTech Connect

    Morris, S.C.

    1992-08-01

    Fuel-cycle analysis if not the same as life-cycle analysis, although the focus on defining a comprehensive system for analysis leads toward the same path. This approach was the basis of the Brookhaven Reference Energy System. It provided a framework for summing total effects over an explicitly defined fuel cycle. This concept was computerized and coupled with an extensive data base in ESNS -- the Energy Systems Network Simulator. As an example, ESNS was the analytical basis for a comparison of health and environmental effects of several coal conversion technologies. With advances in computer systems and methods, however, ESNS has not been maintained at Brookhaven. The RES approach was one of the bases of the OECD COMPASS Project and the UNEP comparative assessment of environmental impacts of energy sources. An RES model alone has limitations in analyzing complex energy systems, e.g., it is difficult to handle feedback in the network. The most recent version of a series of optimization models is MARKAL, a dynamic linear programming model now used to assess strategies to reduce greenhouse gas emissions from the energy system. MARKAL creates an optimal set of reference energy systems over multiple time periods, automatically incorporating dynamic feedback and allowing fuel switching and end-use conservation to meet useful energy demands.

  3. Life cycle analysis of energy systems: Methods and experience

    SciTech Connect

    Morris, S.C.

    1992-01-01

    Fuel-cycle analysis if not the same as life-cycle analysis, although the focus on defining a comprehensive system for analysis leads toward the same path. This approach was the basis of the Brookhaven Reference Energy System. It provided a framework for summing total effects over an explicitly defined fuel cycle. This concept was computerized and coupled with an extensive data base in ESNS -- the Energy Systems Network Simulator. As an example, ESNS was the analytical basis for a comparison of health and environmental effects of several coal conversion technologies. With advances in computer systems and methods, however, ESNS has not been maintained at Brookhaven. The RES approach was one of the bases of the OECD COMPASS Project and the UNEP comparative assessment of environmental impacts of energy sources. An RES model alone has limitations in analyzing complex energy systems, e.g., it is difficult to handle feedback in the network. The most recent version of a series of optimization models is MARKAL, a dynamic linear programming model now used to assess strategies to reduce greenhouse gas emissions from the energy system. MARKAL creates an optimal set of reference energy systems over multiple time periods, automatically incorporating dynamic feedback and allowing fuel switching and end-use conservation to meet useful energy demands.

  4. HEPDOOP: High-Energy Physics Analysis using Hadoop

    NASA Astrophysics Data System (ADS)

    Bhimji, W.; Bristow, T.; Washbrook, A.

    2014-06-01

    We perform a LHC data analysis workflow using tools and data formats that are commonly used in the "Big Data" community outside High Energy Physics (HEP). These include Apache Avro for serialisation to binary files, Pig and Hadoop for mass data processing and Python Scikit-Learn for multi-variate analysis. Comparison is made with the same analysis performed with current HEP tools in ROOT.

  5. Sustainable Biofuel Project: Emergy Analysis of South Florida Energy Crops

    SciTech Connect

    Amponsah, Nana Yaw; Izursa, Jose-Luis; Hanlon, Edward A.; Capece, John C.

    2012-11-15

    This study evaluates the sustainability of various farming systems, namely (1) sugarcane on organic and mineral soils and (2) energycane and sweet sorghum on mineral soils. The primary objective of the study is to compare the relative sustainability matrices of these energy crops and their respective farming systems. These matrices should guide decision and policy makers to determine the overall sustainability of an intended or proposed bioethanol project related to any of these studied crops. Several different methods of energy analysis have been proposed to assess the feasibility or sustainability of projects exploiting natural resources (such as (Life Cycle Analysis, Energy Analysis, Exergy Analysis, Cost Benefit Analysis, Ecological Footprint, etc.). This study primarily focused on the concept of Emergy Analysis, a quantitative analytical technique for determining the values of nonmonied and monied resources, services and commodities in common units of the solar energy it took to make them. With this Emergy Analysis study, the Hendry County Sustainable Biofuels Center intends to provide useful perspective for different stakeholder groups to (1) assess and compare the sustainability levels of above named crops cultivation on mineral soils and organic soils for ethanol production and (2) identify processes within the cultivation that could be targeted for improvements. The results provide as much insight into the assumptions inherent in the investigated approaches as they do into the farming systems in this study.

  6. ACCURATE MEASUREMENT OF THE ENERGY DEPENDENCE OF THE PROCESS e+ + e- → e± + e∓, IN THE s-RANGE 1.44-9.0 GeV2

    NASA Astrophysics Data System (ADS)

    Bernardini, M.; Bollini, D.; Brunini, P. L.; Fiorentino, E.; Massam, T.; Monari, L.; Palmonari, F.; Rimondi, F.; Zichichi, A.

    The analysis of 12 827 e+ + e- → e± + e∓ events observed in the s-range 1.44-9.0 GeV2 allows measurement of the energy dependence of the cross-section for the most typical QED process, with ±2% accuracy. Within this limit the data follow QED, with first-order radiative corrections included.

  7. Geothermal Energy Development in the Eastern United States, Sensitivity analysis-cost of geothermal energy

    SciTech Connect

    Kane, S.M.; Kroll, P.; Nilo, B.

    1982-12-01

    The Geothermal Resources Interactive Temporal Simulation (GRITS) model is a computer code designed to estimate the costs of geothermal energy systems. The interactive program allows the user to vary resource, demand, and financial parameters to observe their effects on delivered costs of direct-use geothermal energy. Due to the large number and interdependent nature of the variables that influence these costs, the variables can be handled practically only through computer modeling. This report documents a sensitivity analysis of the cost of direct-use geothermal energy where each major element is varied to measure the responsiveness of cost to changes in that element. It is hoped that this analysis will assist those persons interested in geothermal energy to understand the most significant cost element as well as those individuals interested in using the GRITS program in the future.

  8. Proceedings of the 1987 socioeconomic energy research and analysis conference

    SciTech Connect

    Not Available

    1990-08-01

    The Department of Energy (the Department) convened the first Socioeconomic Energy Research and Analysis Conference in May 1987, in the spirit of constructive dialogue and mutual concern about numerous energy issues and problems. The objective was to provide a national forum for illuminating specific energy and related socioeconomic issues of our nation and discussing realistic approaches to energy policy assessments. This action was based on the Department's commitment to lead the way in developing a pragmatic framework or energy policy determinations, by incorporating constructive policy impact assessment methods into the decisionmaking process. In this rapidly developing industry with high energy technologies, a strong federal role and targeted government programs are essential for the development and integration of minorities into various industry segments. Furthermore, a responsive energy program for all segments of the population must be sensitive to (a) the impact of energy policies on the overall growth of the economy; (b) the differential impact of energy policies on various industries; and (c) the pattern of change in the structure of the social environment. The socioeconomic researchers and energy policy analysts who presented papers or participated in this national forum assisted the Department's efforts to build an energy structure which is truly responsive to the needs of the various population segmets of our nation. The conference participants were also given the opportunity to critique some unique energy policy assessment methodologies which have been conducted mainly at Argonne National Laboratory, under the sponsorship and guidance of the Research and Education Divisions of my Office. Individual papers, in this proceedings have been cataloged separately.

  9. Analysis of surface energy balance closure over heterogeneous surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Soojin; Lee, Young-Hee; Kim, Kyu Rang; Park, Young-San

    2014-11-01

    Surface energy balance closure has been examined using eddy covariance measurements and other observations at one industrial and three agricultural sites near the Nakdong River during daytime. Energy balance closure was evaluated by calculating the long-term averaged energy balance ratio (EBR), the ratio of turbulent energy fluxes to available energy, and the statistical regression of turbulent energy fluxes against available energy using half-hourly data. The EBR of all sites ranges from 0.46 to 0.83 while the coefficient of determination ( R 2) ranges from 0.37 to 0.77. The energy balance closure was relatively poor compared to homogeneous sites, indicating the influence of surface heterogeneity. Unmeasured heat storage terms also seem to play a role in the surface energy budget at the industrial and irrigated sites. The energy balance closure was better in conditions of high wind speed, low downward short wave radiation, and high friction velocity, which suggests the role of heat storage term and surface heterogeneity in surface energy balance at these sites. Spectrum analysis shows a sharp roll-off at the low frequency in co-spectrum, which indicates that low-frequency motions do not significantly contribute to turbulent fluxes. Both the spectra and cospectra in unstable conditions show a broad peak indicating the influence of multiple sizes of large eddies over heterogeneous sites. Most of ogive curves for the kinematic latent and sensible heat fluxes reach an asymptote within 30 minutes regardless of the EBR value, indicating that low frequency motion is not a main factor for energy imbalance. However, stationary eddies due to landscape heterogeneity still remains as a possible cause for energy imbalance.

  10. Pebbles and PebbleJuggler: software for accurate, unbiased, and fast measurement and analysis of nanoparticle morphology from transmission electron microscopy (TEM) micrographs

    NASA Astrophysics Data System (ADS)

    Mondini, S.; Ferretti, A. M.; Puglisi, A.; Ponti, A.

    2012-08-01

    Pebbles is a user-friendly software program which implements an accurate, unbiased, and fast method to measure the morphology of a population of nanoparticles (NPs) from TEM micrographs. The morphological parameters of the projected NP shape are obtained by fitting intensity models to the TEM micrograph. Pebbles can be used either in automatic mode, where both fitting and validation are reliably carried out with minimal human intervention, and in manual mode, where the user has full control on the fitting and validation steps. Accuracy in diameter measurement has been shown to be <~1%. When operated in automatic mode, Pebbles can be very fast. The effective speed of 1 NP s-1 has been achieved in favorable cases (packed monolayer of NPs). Since Pebbles is based on a local modeling procedure, it successfully treats cases such as low contrast NPs, NPs with significant diffraction scattering, and inhomogeneous background which often make conventional thresholding procedures fail. Pebbles is accompanied by PebbleJuggler, a software program for the statistical analysis of the sets of best-fit NP models created by Pebbles. Effort has been devoted to make Pebbles and PebbleJuggler the most user-friendly and the least user-tedious we could. Pebbles and PebbleJuggler are available at http://pebbles.istm.cnr.it.Pebbles is a user-friendly software program which implements an accurate, unbiased, and fast method to measure the morphology of a population of nanoparticles (NPs) from TEM micrographs. The morphological parameters of the projected NP shape are obtained by fitting intensity models to the TEM micrograph. Pebbles can be used either in automatic mode, where both fitting and validation are reliably carried out with minimal human intervention, and in manual mode, where the user has full control on the fitting and validation steps. Accuracy in diameter measurement has been shown to be <~1%. When operated in automatic mode, Pebbles can be very fast. The effective speed of 1

  11. Survey and Analysis of Weather Data for Building Energy Simulations

    SciTech Connect

    Bhandari, Mahabir S; Shrestha, Som S; New, Joshua Ryan

    2012-01-01

    In recent years, calibrated energy modeling of residential and commercial buildings has gained importance in a retrofit-dominated market. Accurate weather data plays an important role in this calibration process and projected energy savings. It would be ideal to measure weather data at the building location to capture relevant microclimate variation but this is generally considered cost-prohibitive. There are data sources publicly available with high temporal sampling rates but at relatively poor geospatial sampling locations. To overcome this limitation, there are a growing number of service providers that claim to provide real time and historical weather data for 20-35 km2 grid across the globe. Unfortunately, there is limited documentation from 3rd-party sources attesting to the accuracy of this data. This paper compares provided weather characteristics with data collected from a weather station inaccessible to the service providers. Monthly average dry bulb temperature; relative humidity; direct, diffuse and horizontal solar radiation; and wind speed are statistically compared. Moreover, we ascertain the relative contributions of each weather variable and its impact on building loads. Annual simulations are calculated for three different building types, including a closely monitored and automated energy efficient research building. The comparison shows that the difference for an individual variable can be as high as 90%. In addition