Exogenous attention enhances 2nd-order contrast sensitivity.
Barbot, Antoine; Landy, Michael S; Carrasco, Marisa
2011-05-11
Natural scenes contain a rich variety of contours that the visual system extracts to segregate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention--the involuntary and transient capture of spatial attention--affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer's 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations. PMID:21356228
Exogenous attention enhances 2nd-order contrast sensitivity
Barbot, Antoine; Landy, Michael S.; Carrasco, Marisa
2011-01-01
Natural scenes contain a rich variety of contours that the visual system extracts to segregrate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention—the involuntary and transient capture of spatial attention—affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer’s 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations. PMID:21356228
The transient nature of 2nd-order stereopsis.
Hess, Robert F; Wilcox, Laurie M
2008-05-01
There are currently two competing dichotomies used to describe how local stereoscopic information is processed by the human visual system. The first is in terms of the type of the spatial filtering operations used to extract relevant image features prior to stereoscopic analysis (i.e. 1st- vs 2nd-order stereo; [Hess, R. F., & Wilcox, L. M. (1994). Linear and non-linear filtering in stereopsis. Vision Research, 34, 2431-2438]). The second is in terms of the temporal properties of the mechanisms used to process stereoscopic information (i.e. sustained vs transient stereo; [Schor, C. M., Edwards, M., & Pope, D. R. (1998). Spatial-frequency and contrast tuning of the transient-stereopsis system. Vision Research, 38(20), 3057-3068]). Here we compare the dynamics of 1st- and 2nd-order stereopsis using several types of stimuli and find a clear dissociation in which 1st-order stimuli exhibit sustained properties while 2nd-order patterns show more transient properties. Our results and analyses unify and simplify two complimentary bodies of work. PMID:18407312
1st- and 2nd-order motion and texture resolution in central and peripheral vision
NASA Technical Reports Server (NTRS)
Solomon, J. A.; Sperling, G.
1995-01-01
STIMULI. The 1st-order stimuli are moving sine gratings. The 2nd-order stimuli are fields of static visual texture, whose contrasts are modulated by moving sine gratings. Neither the spatial slant (orientation) nor the direction of motion of these 2nd-order (microbalanced) stimuli can be detected by a Fourier analysis; they are invisible to Reichardt and motion-energy detectors. METHOD. For these dynamic stimuli, when presented both centrally and in an annular window extending from 8 to 10 deg in eccentricity, we measured the highest spatial frequency for which discrimination between +/- 45 deg texture slants and discrimination between opposite directions of motion were each possible. RESULTS. For sufficiently low spatial frequencies, slant and direction can be discriminated in both central and peripheral vision, for both 1st- and for 2nd-order stimuli. For both 1st- and 2nd-order stimuli, at both retinal locations, slant discrimination is possible at higher spatial frequencies than direction discrimination. For both 1st- and 2nd-order stimuli, motion resolution decreases 2-3 times more rapidly with eccentricity than does texture resolution. CONCLUSIONS. (1) 1st- and 2nd-order motion scale similarly with eccentricity. (2) 1st- and 2nd-order texture scale similarly with eccentricity. (3) The central/peripheral resolution fall-off is 2-3 times greater for motion than for texture.
The 2nd-order Post-Newtonian Orbit Equation of Light
NASA Astrophysics Data System (ADS)
Xiao, Yu; Fei, Bao-Jun; Sun, Wei-Jin; Ji, Cheng-Xiang
2008-10-01
Based on the 2nd-order post-Newtonian approximation under the DSX frame of the general relativity theory, the 2nd-order post-Newtonian orbital equation of light in the axis-symmetrical stationary spacetime is derived, and from this, the angle of deflection of light propagating in the equatorial plane is derived. The obtained results are consistent with those of the Schwarzchild and Kerr metrics within the limits of measuring precision.
Four-dimensional investigation of the 2nd order volume autocorrelation technique
NASA Astrophysics Data System (ADS)
Faucher, O.; Tzallas, P.; Benis, E. P.; Kruse, J.; Peralta Conde, A.; Kalpouzos, C.; Charalambidis, D.
2009-10-01
The 2nd order volume autocorrelation technique, widely utilized in directly measuring ultra-short light pulses durations, is examined in detail via model calculations that include three-dimensional integration over a large ionization volume, temporal delay and spatial displacement of the two beams of the autocorrelator at the focus. The effects of the inherent displacement to the 2nd order autocorrelation technique are demonstrated for short and long pulses, elucidating the appropriate implementation of the technique in tight focusing conditions. Based on the above investigations, a high accuracy 2nd order volume autocorrelation measurement of the duration of the 5th harmonic of a 50 fs long laser pulse, including the measurement of the carrier wavelength oscillation, is presented.
2nd-Order CESE Results For C1.1: Transonic Ringleb Flow
NASA Technical Reports Server (NTRS)
Friedlander, David J.
2015-01-01
The Conservation Element and Solution Element (CESE) method was used as implemented in the NASA research code ez4d (an unstructured Navier-Stokes solver coded in C++ with serial and parallel versions available.) The CESE method is a time-accurate formulation with flux-conservation in both space and time. The method treats the discretized derivatives of space and time identically and while the 2nd-order accurate version was used, high-order versions exist.
2nd-Order CESE Results For C1.4: Vortex Transport by Uniform Flow
NASA Technical Reports Server (NTRS)
Friedlander, David J.
2015-01-01
The Conservation Element and Solution Element (CESE) method was used as implemented in the NASA research code ez4d. The CESE method is a time accurate formulation with flux-conservation in both space and time. The method treats the discretized derivatives of space and time identically and while the 2nd-order accurate version was used, high-order versions exist, the 2nd-order accurate version was used. In regards to the ez4d code, it is an unstructured Navier-Stokes solver coded in C++ with serial and parallel versions available. As part of its architecture, ez4d has the capability to utilize multi-thread and Messaging Passage Interface (MPI) for parallel runs.
NASA Technical Reports Server (NTRS)
Kapania, Rakesh K.; Liu, Youhua
2000-01-01
At the preliminary design stage of a wing structure, an efficient simulation, one needing little computation but yielding adequately accurate results for various response quantities, is essential in the search of optimal design in a vast design space. In the present paper, methods of using sensitivities up to 2nd order, and direct application of neural networks are explored. The example problem is how to decide the natural frequencies of a wing given the shape variables of the structure. It is shown that when sensitivities cannot be obtained analytically, the finite difference approach is usually more reliable than a semi-analytical approach provided an appropriate step size is used. The use of second order sensitivities is proved of being able to yield much better results than the case where only the first order sensitivities are used. When neural networks are trained to relate the wing natural frequencies to the shape variables, a negligible computation effort is needed to accurately determine the natural frequencies of a new design.
Computer Generation of Subduction Frequencies for 2ND Order Phase Transitions in Two-Dimensions
NASA Astrophysics Data System (ADS)
Deonarine, Samaroo
The Landau theory of 2nd order phase transitions and Group theory Criteria are used to predict which subgroups G (L-HOOK EQ) G(,0) can occur in transitions for 2-D systems (plane-group to plane-group and diperiodic to diperiodic). Previous work 1 on the 17 plane space groups has been based on the tables of Coxeter & Moser 2 and the International Tables of X-ray Crystallography (ITXRC, 1965) 3 . These tables do not exhaust all the possible subgroups of a space group 4 . Since such explicit tables are non-existent for other families of space groups we have developed algorithms that make a systematic search of the parent unit cell of G(,0) to locate the origin and orientation of all its subgroups G, G (L-HOOK EQ) G(,0). We have written a RATFOR/FORTRAN program for the VAX 11-780 which will generate the subduction frequencies. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). for allowed second order phase transitions in 2-dimensional systems that are describable by the 80 diperiodic Groups G(,0) and G 5 . Our program gives a complete tabulation (Origin, new Translation Sublattice, Subduction Frequency, Subgroup and its Generators) of the allowed continuous or second order phase transitions from a parent diperiodic group G(,0) to another diperiodic subgroup G.
A convective divertor utilizing a 2nd-order magnetic field null
NASA Astrophysics Data System (ADS)
Rognlien, Thomas
2014-10-01
New results motivate a detailed study of a magnetic divertor concept characterized by strong plasma convection near a poloidal magnetic field (Bp) null region. The configuration is that of a near-2nd-order Bp null (Bp ~ Δ r2) , as in a snowflake divertor. The concept has 2 key features: (A) Convection spreads the heat flux between multiple divertor legs and further broadens the heat-flux profile within each leg, thereby greatly reducing target-plate heat loads. (B) The heat flux is further reduced by line radiation in each leg in detachment-like ionization zones. Theory indicates that convective turbulence arises when the poloidal plasma beta, βp = 2μ0nT/B p 2 >> 1 . Measurements in TCV now more fully quantify earlier NSTX and TCV observations of plasma mixing, and related modeling of TCV indicates that strongly enhanced null-region transport is present. Convective mixing provides a stabilizing mechanism to prevent the ionization fronts (hydrogenic and impurity) from collapsing to a highly radiating core MARFE. Also, the radiating zone maps to a very small region at the midplane owing to the very weak Bp in the convective region, thus minimizing its impact on the core plasma. Detailed calculations are reported that combine features A and B noted above. The plasma mixing mechanisms are described together with the corresponding transport model implemented in the 2D UEDGE edge transport code. UEDGE calculations are presented that quantify the roles of mixing, impurity radiation, and detachment stability for a realistic snowflake configuration. Work in collaboration with D.D. Ryutov, S.I. Krasheninnikov, and M.V. Umansky. Performed for the U.S. DoE by LLNS, LLC, LLNL, under Contract DE-AC52-07NA27344.
Order and disorder in Ca 2ND 0.90H 0.10-A structural and thermal study
NASA Astrophysics Data System (ADS)
Verbraeken, Maarten C.; Suard, Emmanuelle; Irvine, John T. S.
2011-08-01
The structure of calcium nitride hydride and its deuterided form has been re-examined at room temperature and studied at high temperature using neutron powder diffraction and thermal analysis. When synthesised at 600 °C, a mixture of both ordered and disordered Ca 2ND 0.90H 0.10 phases results. The disordered phase is the minor component and has a primitive rocksalt structure (spacegroup Fm3 m) with no ordering of D/N on the anion sites and the ordered phase is best described using the rhombohedral spacegroup R-3 m with D and N arranged in alternate layers in (111) planes. This mixture of ordered and disordered phases exists up to 580 °C, at which the loss of deuterium yields Ca 2ND 0.85 with the disappearance of the disordered phase. In the new ordered phase there exists a similar content of vacancies on both anion sites; to achieve this balance, a little N transfers onto the D site, whereas there is no indication of D transferring onto the N-sites. These observations are thought to indicate that the D/N ordering is difficult to achieve with fully occupied anion sites. It has previously been reported that Ca 2ND has an ordered cubic cell with alternating D and N sites in the [100] directions [1]; however, for the samples studied herein, there were clearly two coexisting phases with apparent broadening/splitting of the primitive peaks but not for the ordered peaks. The rhombohedral phase was in fact metrically cubic; however, all the observed peaks were consistent with the rhombohedral unit cell with no peaks requiring the larger ordered cubic unit cell to be utilised. Furthermore this rhombohedral cell displays the same form of N-D ordering as the Sr and Ba analogues, which are metrically rhombohedral.
Brain order disorder 2nd group report of f-EEG
NASA Astrophysics Data System (ADS)
Lalonde, Francois; Gogtay, Nitin; Giedd, Jay; Vydelingum, Nadarajen; Brown, David; Tran, Binh Q.; Hsu, Charles; Hsu, Ming-Kai; Cha, Jae; Jenkins, Jeffrey; Ma, Lien; Willey, Jefferson; Wu, Jerry; Oh, Kenneth; Landa, Joseph; Lin, C. T.; Jung, T. P.; Makeig, Scott; Morabito, Carlo Francesco; Moon, Qyu; Yamakawa, Takeshi; Lee, Soo-Young; Lee, Jong-Hwan; Szu, Harold H.; Kaur, Balvinder; Byrd, Kenneth; Dang, Karen; Krzywicki, Alan; Familoni, Babajide O.; Larson, Louis; Harkrider, Susan; Krapels, Keith A.; Dai, Liyi
2014-05-01
Since the Brain Order Disorder (BOD) group reported on a high density Electroencephalogram (EEG) to capture the neuronal information using EEG to wirelessly interface with a Smartphone [1,2], a larger BOD group has been assembled, including the Obama BRAIN program, CUA Brain Computer Interface Lab and the UCSD Swartz Computational Neuroscience Center. We can implement the pair-electrodes correlation functions in order to operate in a real time daily environment, which is of the computation complexity of O(N3) for N=102~3 known as functional f-EEG. The daily monitoring requires two areas of focus. Area #(1) to quantify the neuronal information flow under arbitrary daily stimuli-response sources. Approach to #1: (i) We have asserted that the sources contained in the EEG signals may be discovered by an unsupervised learning neural network called blind sources separation (BSS) of independent entropy components, based on the irreversible Boltzmann cellular thermodynamics(ΔS < 0), where the entropy is a degree of uniformity. What is the entropy? Loosely speaking, sand on the beach is more uniform at a higher entropy value than the rocks composing a mountain - the internal binding energy tells the paleontologists the existence of information. To a politician, landside voting results has only the winning information but more entropy, while a non-uniform voting distribution record has more information. For the human's effortless brain at constant temperature, we can solve the minimum of Helmholtz free energy (H = E - TS) by computing BSS, and then their pairwise-entropy source correlation function. (i) Although the entropy itself is not the information per se, but the concurrence of the entropy sources is the information flow as a functional-EEG, sketched in this 2nd BOD report. Area #(2) applying EEG bio-feedback will improve collective decision making (TBD). Approach to #2: We introduce a novel performance quality metrics, in terms of the throughput rate of faster (
Brain order disorder 2nd group report of f-EEG
NASA Astrophysics Data System (ADS)
Lalonde, Francois; Gogtay, Nitin; Giedd, Jay; Vydelingum, Nadarajen; Brown, David; Tran, Binh Q.; Hsu, Charles; Hsu, Ming-Kai; Cha, Jae; Jenkins, Jeffrey; Ma, Lien; Willey, Jefferson; Wu, Jerry; Oh, Kenneth; Landa, Joseph; Lin, C. T.; Jung, T. P.; Makeig, Scott; Morabito, Carlo Francesco; Moon, Qyu; Yamakawa, Takeshi; Lee, Soo-Young; Lee, Jong-Hwan; Szu, Harold H.; Kaur, Balvinder; Byrd, Kenneth; Dang, Karen; Krzywicki, Alan; Familoni, Babajide O.; Larson, Louis; Harkrider, Susan; Krapels, Keith A.; Dai, Liyi
2014-05-01
Since the Brain Order Disorder (BOD) group reported on a high density Electroencephalogram (EEG) to capture the neuronal information using EEG to wirelessly interface with a Smartphone [1,2], a larger BOD group has been assembled, including the Obama BRAIN program, CUA Brain Computer Interface Lab and the UCSD Swartz Computational Neuroscience Center. We can implement the pair-electrodes correlation functions in order to operate in a real time daily environment, which is of the computation complexity of O(N3) for N=102~3 known as functional f-EEG. The daily monitoring requires two areas of focus. Area #(1) to quantify the neuronal information flow under arbitrary daily stimuli-response sources. Approach to #1: (i) We have asserted that the sources contained in the EEG signals may be discovered by an unsupervised learning neural network called blind sources separation (BSS) of independent entropy components, based on the irreversible Boltzmann cellular thermodynamics(ΔS < 0), where the entropy is a degree of uniformity. What is the entropy? Loosely speaking, sand on the beach is more uniform at a higher entropy value than the rocks composing a mountain - the internal binding energy tells the paleontologists the existence of information. To a politician, landside voting results has only the winning information but more entropy, while a non-uniform voting distribution record has more information. For the human's effortless brain at constant temperature, we can solve the minimum of Helmholtz free energy (H = E - TS) by computing BSS, and then their pairwise-entropy source correlation function. (i) Although the entropy itself is not the information per se, but the concurrence of the entropy sources is the information flow as a functional-EEG, sketched in this 2nd BOD report. Area #(2) applying EEG bio-feedback will improve collective decision making (TBD). Approach to #2: We introduce a novel performance quality metrics, in terms of the throughput rate of faster (
NASA Astrophysics Data System (ADS)
Boyle, C.; Sigler, C.; Kirch, J. D.; Lindberg, D.; Earles, T.; Botez, D.; Mawst, L. J.
2016-03-01
Grating-coupled, surface-emitting (GCSE) quantum-cascade lasers (QCLs) are demonstrated with high-power, single-lobe surface emission. A 2nd-order Au-semiconductor distributed-feedback (DFB)/ distributed-Bragg-reflector (DBR) grating is used for feedback and out-coupling. The DFB and DBR grating regions are 2.55 mm- and 1.28 mm-long, respectively, for a total grating length of 5.1 mm. The lasers are designed to operate in a symmetric longitudinal mode by causing resonant coupling of the guided optical mode to the antisymmetric surface-plasmon modes of the 2nd-order metal/semiconductor grating. In turn, the antisymmetric longitudinal modes are strongly absorbed by the metal in the grating, causing the symmetric longitudinal mode to be favored to lase, which produces a single lobe beam over a grating duty-cycle range of 36-41 %. Simulations indicate that the symmetric mode is always favored to lase, independent of the random phase of residual reflections from the device's cleaved ends. Peak pulsed output powers of ~ 0.4 W were measured with single-lobe, single-mode operation near 4.75 μm.
Wang, C-X. )
2012-04-25
Optimization of nonlinear driving terms have become a useful tool for designing storage rings, especially modern light sources where the strong nonlinearity is dominated by the large chromatic effects of quadrupoles and strong sextupoles for chromaticity control. The Lie algebraic method is well known for computing such driving terms. However, it appears that there was a lack of explicit formulas in the public domain for such computation, resulting in uncertainty and/or inconsistency in widely used codes. This note presents explicit formulas for driving terms due to sextupoles and chromatic effects of quadrupoles, which can be considered as thin elements. The computation is accurate to the 4th-order Hamiltonian and 2nd-order in terms of magnet parameters. The results given here are the same as the APS internal note AOP-TN-2009-020. This internal nte has been revised and published here as a Light Source Note in order to get this information into the public domain, since both ELEGANT and OPA are using these formulas.
NASA Astrophysics Data System (ADS)
de Lima, João L. M. P.; Canhoto, Cristina
2015-04-01
What will happen when water temperatures of streams increases, due to climate changes or in connection with rapidly changing human systems? Trying to answer to this question a whole-stream manipulative experiment was undertaken, where an increase in water temperature was artificially induced on a 2nd order stream reach. The main objective of this poster is to describe this experiment focusing on the design of the hydraulic system. The system maintained a steady flow while allowing natural variation in abiotic factors and was successfully used to evaluate the effects of warming on a stream ecosystem at several levels of biological organization. A constant flow of stream water was controlled by a hydraulic setup (~22m long; ~1.5m width) subdivided into two independent channels. One channel of the study reach received heated water (~3°C above the other), while the other received water at stream ambient temperature. The warming system maintained a steady gravity controlled flow making use of weirs and valves.
Topological quantum order: Stability under local perturbations
Bravyi, Sergey; Hastings, Matthew B.; Michalakis, Spyridon
2010-09-15
We study zero-temperature stability of topological phases of matter under weak time-independent perturbations. Our results apply to quantum spin Hamiltonians that can be written as a sum of geometrically local commuting projectors on a D-dimensional lattice with certain topological order conditions. Given such a Hamiltonian H{sub 0}, we prove that there exists a constant threshold {epsilon}>0 such that for any perturbation V representable as a sum of short-range bounded-norm interactions, the perturbed Hamiltonian H=H{sub 0}+{epsilon}V has well-defined spectral bands originating from low-lying eigenvalues of H{sub 0}. These bands are separated from the rest of the spectra and from each other by a constant gap. The band originating from the smallest eigenvalue of H{sub 0} has exponentially small width (as a function of the lattice size). Our proof exploits a discrete version of Hamiltonian flow equations, the theory of relatively bounded operators, and the Lieb-Robinson bound.
Structural and magnetic study of order-disorder behavior in the double perovskites Ba2Nd1-xMnxMoO6.
Coomer, Fiona C; Cussen, Edmund J
2014-01-21
The synthesis and structural and magnetic characterization of the site-ordered double perovskites, Ba2Nd1-xMnxMoO6, 0 < x ≤ 1, are reported in order to show the effect of doping Jahn-Teller active, S = 1/2, Mo(5+) into the structure of Ba2MnMoO6, which exhibits anomalous long-range antiferromagnetic order. Rietveld refinements against room temperature neutron powder diffraction data indicate that the tetragonal distortion present in the Ba2NdMoO6 end member persists to x ≤ 0.3. This is predominantly manifested as a tilting of the MO6 octahedra, and there is no evidence of any structural phase transitions on cooling to 1.5 K. For x > 0.3, no deviation from the ideal cubic Fm3̅m symmetry is observed. Furthermore, dc-susceptibility measurements confirm that Mn(2+) is being doped onto the Nd(3+) site, and the associated oxidation of Mo(5+) to Mo(6+). For all compositions, the Curie-Weiss paramagnetic behavior above 150 K indicates negative Weiss constants that range from -24(2) and -85(2) K. This net antiferromagnetic interaction is weakest when x ≈ 0.5, where the disorder in cation site occupancy and competition with ferromagnetic interactions is the greatest. Despite these strong antiferromagnetic interactions, there is no evidence in the dc-susceptibility of a bulk cancellation of spins for x > 0.05. Low-temperature neutron diffraction measurements indicate that there is no long-range magnetic order for 0.1 ≤ x < 0.9. Ba2Nd0.10Mn0.90MoO6 exhibits additional Bragg scattering at 2 K, indicative of long-range antiferromagnetic ordering of the Mn(2+) cations, with a propagation vector k = (1/2, 1/2, 1/2). The scattering intensities can be modeled using a noncollinear magnetic structure with the Mn(2+) moments orientated antiferromagnetically along the four different ⟨111⟩ directions. PMID:24392887
DNS and LES of Turbulent Backward-Facing Step Flow Using 2ND-and 4TH-Order Discretization
NASA Astrophysics Data System (ADS)
Meri, Adnan; Wengle, Hans
Results are presented from a Direct Numerical Simulation (DNS) and Large-Eddy Simulations (LES) of turbulent flow over a backward-facing step (Reh=3300) with a fully developed channel flow (Rcτ=180) utilized asatime-dependent inflow condition. Numerical solutions using a fourth-order compact (Hermitian) scheme, which was formulated directly for anon-equidistant and staggered grid in [1] are compared with numerical solutions using the classical second-order central scheme. There sults from LES (using the dynamic subgrid scale model) are evaluated against a corresponding DNS reference data set (fourth-order solution).
NASA Astrophysics Data System (ADS)
Cacuci, Dan G.
2015-03-01
This work presents an illustrative application of the second-order adjoint sensitivity analysis methodology (2nd-ASAM) to a paradigm neutron diffusion problem, which is sufficiently simple to admit an exact solution, thereby making transparent the underlying mathematical derivations. The general theory underlying 2nd-ASAM indicates that, for a physical system comprising Nα parameters, the computation of all of the first- and second-order response sensitivities requires (per response) at most (2Nα + 1) "large-scale" computations using the first-level and, respectively, second-level adjoint sensitivity systems (1st-LASS and 2nd-LASS). Very importantly, however, the illustrative application presented in this work shows that the actual number of adjoint computations needed for computing all of the first- and second-order response sensitivities may be significantly less than (2Nα + 1) per response. For this illustrative problem, four "large-scale" adjoint computations sufficed for the complete and exact computations of all 4 first- and 10 distinct second-order derivatives. Furthermore, the construction and solution of the 2nd-LASS requires very little additional effort beyond the construction of the adjoint sensitivity system needed for computing the first-order sensitivities. Very significantly, only the sources on the right-sides of the diffusion (differential) operator needed to be modified; the left-side of the differential equations (and hence the "solver" in large-scale practical applications) remained unchanged. All of the first-order relative response sensitivities to the model parameters have significantly large values, of order unity. Also importantly, most of the second-order relative sensitivities are just as large, and some even up to twice as large as the first-order sensitivities. In the illustrative example presented in this work, the second-order sensitivities contribute little to the response variances and covariances. However, they have the
Multifield cosmological perturbations at third order and the ekpyrotic trispectrum
Lehners, Jean-Luc; Renaux-Petel, Sebastien
2009-09-15
Using the covariant formalism, we derive the equations of motion for adiabatic and entropy perturbations at third order in perturbation theory for cosmological models involving two scalar fields. We use these equations to calculate the trispectrum of ekpyrotic and cyclic models in which the density perturbations are generated via the entropic mechanism. In these models, the conversion of entropy into curvature perturbations occurs just before the big bang, either during the ekpyrotic phase or during the subsequent kinetic energy dominated phase. In both cases, we find that the nonlinearity parameters f{sub NL} and g{sub NL} combine to leave a very distinct observational imprint.
NASA Astrophysics Data System (ADS)
Park, Jun-Hyub; Shin, Myung-Soo; Kang, Dong-Joong; Lim, Sung-Jo; Ha, Jong-Eun
In this study, a system for non-contact in-situ measurement of strain during tensile test of thin films by using CCD camera with marking surface of specimen by black pen was implemented as a sensing device. To improve accuracy of measurement when CCD camera is used, this paper proposed a new method for measuring strain during tensile test of specimen with micrometer size. The size of pixel of CCD camera determines resolution of measurement, but the size of pixel can not satisfy the resolution required in tensile test of thin film because the extension of the specimen is very small during the tensile test. To increase resolution of measurement, the suggested method performs an accurate subpixel matching by applying 2nd order polynomial interpolation method to the conventional template matching. The algorithm was developed to calculate location of subpixel providing the best matching value by performing single dimensional polynomial interpolation from the results of pixel-based matching at a local region of image. The measurement resolution was less than 0.01 times of original pixel size. To verify the reliability of the system, the tensile test for the BeNi thin film was performed, which is widely used as a material in micro-probe tip. Tensile tests were performed and strains were measured using the proposed method and also the capacitance type displacement sensor for comparison. It is demonstrated that the new strain measurement system can effectively describe a behavior of materials after yield during the tensile test of the specimen at microscale with easy setup and better accuracy.
Complete Hamiltonian analysis of cosmological perturbations at all orders
NASA Astrophysics Data System (ADS)
Nandi, Debottam; Shankaranarayanan, S.
2016-06-01
In this work, we present a consistent Hamiltonian analysis of cosmological perturbations at all orders. To make the procedure transparent, we consider a simple model and resolve the `gauge-fixing' issues and extend the analysis to scalar field models and show that our approach can be applied to any order of perturbation for any first order derivative fields. In the case of Galilean scalar fields, our procedure can extract constrained relations at all orders in perturbations leading to the fact that there is no extra degrees of freedom due to the presence of higher time derivatives of the field in the Lagrangian. We compare and contrast our approach to the Lagrangian approach (Chen et al. [2006]) for extracting higher order correlations and show that our approach is efficient and robust and can be applied to any model of gravity and matter fields without invoking slow-roll approximation.
Stochastic systems with delay: Perturbation theory for second order statistics
NASA Astrophysics Data System (ADS)
Frank, T. D.
2016-03-01
Within the framework of delay Fokker-Planck equations, a perturbation theoretical method is developed to determine second-order statistical quantities such as autocorrelation functions for stochastic systems with delay. Two variants of the perturbation theoretical approach are presented. The first variant is based on a non-local Fokker-Planck operator. The second variant requires to solve a Fokker-Planck equation with source term. It is shown that the two variants yield consistent results. The perturbation theoretical approaches are applied to study negative autocorrelations that are induced by feedback delays and mediated by the strength of the fluctuating forces that act on the feedback systems.
The Morse Oscillator and Second-Order Perturbation Theory
NASA Astrophysics Data System (ADS)
Pettitt, B. A.
1998-09-01
This article shows how the energies of the Morse oscillator are obtained exactly from a second-order perturbation expansion in a harmonic oscillator basis. This exercise is recommended for its instructional value in intermediate quantum chemistry, in that the second-order term is entirely tractable, it arises within an important context (anharmonicity of vibrations), and it gives the right answer.
NASA Astrophysics Data System (ADS)
Liu, Shuxiao; Tang, Yougang; Li, Wei
2016-06-01
In this study, we consider first- and second-order random wave loads and the effects of time-varying displacement volume and transient wave elevation to establish motion equations of the Spar platform's coupled heave-pitch. We generated random wave loads based on frequency-domain wave load transfer functions and the Joint North Sea Wave Project (JONSWAP) wave spectrum, designed program codes to solve the motion equations, and then simulated the coupled heave-pitch motion responses of the platform in the time domain. We then calculated and compared the motion responses in different sea conditions and separately investigated the effects of second-order random wave loads and transient wave elevation. The results show that the coupled heave-pitch motion responses of the platform are primarily dominated by wave height and the characteristic wave period, the latter of which has a greater impact. Second-order mean wave loads mainly affect the average heave value. The platform's pitch increases after the second-order low frequency wave loads are taken into account. The platform's heave is underestimated if the transient wave elevation term in the motion equations is neglected.
Nonperturbative Quantum Physics from Low-Order Perturbation Theory
NASA Astrophysics Data System (ADS)
Mera, Héctor; Pedersen, Thomas G.; Nikolić, Branislav K.
2015-10-01
The Stark effect in hydrogen and the cubic anharmonic oscillator furnish examples of quantum systems where the perturbation results in a certain ionization probability by tunneling processes. Accordingly, the perturbed ground-state energy is shifted and broadened, thus acquiring an imaginary part which is considered to be a paradigm of nonperturbative behavior. Here we demonstrate how the low order coefficients of a divergent perturbation series can be used to obtain excellent approximations to both real and imaginary parts of the perturbed ground state eigenenergy. The key is to use analytic continuation functions with a built-in singularity structure within the complex plane of the coupling constant, which is tailored by means of Bender-Wu dispersion relations. In the examples discussed the analytic continuation functions are Gauss hypergeometric functions, which take as input fourth order perturbation theory and return excellent approximations to the complex perturbed eigenvalue. These functions are Borel consistent and dramatically outperform widely used Padé and Borel-Padé approaches, even for rather large values of the coupling constant.
A simple extrapolation of thermodynamic perturbation theory to infinite order.
Ghobadi, Ahmadreza F; Elliott, J Richard
2015-09-21
Recent analyses of the third and fourth order perturbation contributions to the equations of state for square well spheres and Lennard-Jones chains show trends that persist across orders and molecular models. In particular, the ratio between orders (e.g., A3/A2, where A(i) is the ith order perturbation contribution) exhibits a peak when plotted with respect to density. The trend resembles a Gaussian curve with the peak near the critical density. This observation can form the basis for a simple recursion and extrapolation from the highest available order to infinite order. The resulting extrapolation is analytic and therefore cannot fully characterize the critical region, but it remarkably improves accuracy, especially for the binodal curve. Whereas a second order theory is typically accurate for the binodal at temperatures within 90% of the critical temperature, the extrapolated result is accurate to within 99% of the critical temperature. In addition to square well spheres and Lennard-Jones chains, we demonstrate how the method can be applied semi-empirically to the Perturbed Chain - Statistical Associating Fluid Theory (PC-SAFT). PMID:26395687
A simple extrapolation of thermodynamic perturbation theory to infinite order
Ghobadi, Ahmadreza F.; Elliott, J. Richard
2015-09-21
Recent analyses of the third and fourth order perturbation contributions to the equations of state for square well spheres and Lennard-Jones chains show trends that persist across orders and molecular models. In particular, the ratio between orders (e.g., A{sub 3}/A{sub 2}, where A{sub i} is the ith order perturbation contribution) exhibits a peak when plotted with respect to density. The trend resembles a Gaussian curve with the peak near the critical density. This observation can form the basis for a simple recursion and extrapolation from the highest available order to infinite order. The resulting extrapolation is analytic and therefore cannot fully characterize the critical region, but it remarkably improves accuracy, especially for the binodal curve. Whereas a second order theory is typically accurate for the binodal at temperatures within 90% of the critical temperature, the extrapolated result is accurate to within 99% of the critical temperature. In addition to square well spheres and Lennard-Jones chains, we demonstrate how the method can be applied semi-empirically to the Perturbed Chain - Statistical Associating Fluid Theory (PC-SAFT)
Perturbations of matter fields in the second-order gauge-invariant cosmological perturbation theory
NASA Astrophysics Data System (ADS)
Nakamura, Kouji
2009-12-01
To show that the general framework of the second-order gauge-invariant perturbation theory developed by K. Nakamura [Prog. Theor. Phys. 110, 723 (2003)PTPKAV0033-068X10.1143/PTP.110.723; Prog. Theor. Phys. 113, 481 (2005)PTPKAV0033-068X10.1143/PTP.113.481] is applicable to a wide class of cosmological situations, some formulas for the perturbations of the matter fields are summarized within the framework of the second-order gauge-invariant cosmological perturbation theory in a four-dimensional homogeneous isotropic universe, which is developed in Prog. Theor. Phys. 117, 17 (2007)PTPKAV0033-068X10.1143/PTP.117.17. We derive the formulas for the perturbations of the energy-momentum tensors and equations of motion for a perfect fluid, an imperfect fluid, and a single scalar field, and show that all equations are derived in terms of gauge-invariant variables without any gauge fixing. Through these formulas, we may say that the decomposition formulas for the perturbations of any tensor field into gauge-invariant and gauge-variant parts, which are proposed in the above papers, are universal.
A High Order Perturbation Analysis of the Sitnikov Problem
NASA Astrophysics Data System (ADS)
Hagel, Johannes; Lhotka, Christoph
2005-09-01
The Sitnikov problem is one of the most simple cases of the elliptic restricted three body system. A massless body oscillates along a line (z) perpendicular to a plane (x,y) in which two equally massive bodies, called primary masses, perform Keplerian orbits around their common barycentre with a given eccentricity e. The crossing point of the line of motion of the third mass with the plane is equal to the centre of gravity of the entire system. In spite of its simple geometrical structure, the system is nonlinear and explicitly time dependent. It is globally non integrable and therefore represents an interesting application for advanced perturbative methods. In the present work a high order perturbation approach to the problem was performed, by using symbolic algorithms written in Mathematica. Floquet theory was used to derive solutions of the linearized equation up to 17th order in e. In this way precise analytical expressions for the stability of the system were obtained. Then, applying the Courant and Snyder transformation to the nonlinear equation, algebraic solutions of seventh order in z and e were derived using the method of Poincaré Lindstedt. The enormous amount of necessary computations were performed by extensive use of symbolic programming. We developed automated and highly modularized algorithms in order to master the problem of ordering an increasing number of algebraic terms originating from high order perturbation theory.
Collins, Oonagh M.; Cussen, Edmund J.
2013-04-15
The cation ordered perovskites Ba{sub 2}Nd{sub 1−x}Y{sub x}MoO{sub 6} (0.04≤x≤0.35) have been synthesised by solid-state techniques under reducing conditions at temperatures up to 1350 °C. Rietveld analyses of X-ray and neutron powder diffraction data show that these compounds adopt a tetragonally distorted perovskite structure. The tetragonal distortion is driven by the bonding requirements of the Ba{sup 2+} cation that occupies the central interstice of the perovskite; this cation would be underbonded if these compounds retained the cubic symmetry exhibited by the prototypical structure. The size and charge difference between the lanthanides and Mo{sup 5+} lead to complete ordering of the cations to give a rock-salt ordering of Nd{sup 3+}/Y{sup 3+}O{sub 6} and MoO{sub 6} octahedra. The I4/m space group symmetry is retained on cooling the x=0.1, 0.2 and 0.35 samples to low temperature ca. 2 K. Ba{sub 2}Nd{sub 0.90}Y{sub 0.10}MoO{sub 6} undergoes a gradual distortion of the MoO{sub 6} units on cooling from room temperature to give two long trans bonds (2.001(2) Å) along the z-direction and four shorter apical bonds (1.9563(13) Å) in the xy-plane. This distortion of the MoO{sub 6} units stabilises the 4d{sup 1} electron in the d{sub xz} and d{sub yz} orbitals whilst the d{sub xy} orbital is increased in energy due to the contraction of the Mo–O bonds in the xy-plane. This bond extension along z is propagated through the structure and gives a negative thermal expansion of −13×10{sup −6} K{sup −1} along c. The overall volumetric thermal expansion is positive due to conventional expansion along the other two crystallographic axes. With increasing Y{sup 3+} content this distortion is reduced in x=0.2 and eliminated in x=0.35 which contains largely regular MoO{sub 6} octahedra. The x=0.1 and x=0.2 show small peaks in the neutron diffraction profile due to long range antiferromagnetic order arising from ordered moments of ca. 2 μ{sub B}. - Graphical
High-order primordial perturbations with quantum gravitational effects
NASA Astrophysics Data System (ADS)
Zhu, Tao; Wang, Anzhong; Kirsten, Klaus; Cleaver, Gerald; Sheng, Qin
2016-06-01
In this paper, we provide a systematic investigation of high-order primordial perturbations with nonlinear dispersion relations due to quantum gravitational effects in the framework of uniform asymptotic approximations. Because of these effects, the equation of motion of the mode function in general has multiple turning points. After obtaining analytically approximated solutions to any order in different regions, associated with different types of turning points, we match them to the third one. To this order the errors are less than 0.15%. General expressions of the power spectra of the primordial tensor and scalar perturbations are derived explicitly. We also investigate effects of backreactions of the quantum gravitational corrections, and make sure that inflation lasts long enough in order to solve the underlying problems, such as flatness, horizon, and monopole. Then we study various features of the spectra that are observationally relevant. In particular, under a moderate assumption about the energy scale of the underlying theory of quantum gravity, we have shown that the quantum gravitational effects may alter significantly the ratio between the tensor and scalar power spectra, thereby providing a natural mechanism to alleviate the tension between observations and certain inflationary models, including the one with a quadratic potential.
Non-Gaussianity from the second-order cosmological perturbation
NASA Astrophysics Data System (ADS)
Lyth, David H.; Rodríguez, Yeinzon
2005-06-01
Several conserved and/or gauge-invariant quantities described as the second-order curvature perturbation have been given in the literature. We revisit various scenarios for the generation of second-order non-Gaussianity in the primordial curvature perturbation ζ, employing for the first time a unified notation and focusing on the normalization fNL of the bispectrum. When ζ first appears a few Hubble times after horizon exit, |fNL| is much less than 1 and is, therefore, negligible. Thereafter ζ (and hence fNL) is conserved as long as the pressure is a unique function of energy density (adiabatic pressure). Nonadiabatic pressure comes presumably only from the effect of fields, other than the one pointing along the inflationary trajectory, which are light during inflation (“light noninflaton fields”). During single-component inflation fNL is constant, but multicomponent inflation might generate |fNL|˜1 or bigger. Preheating can affect fNL only in atypical scenarios where it involves light noninflaton fields. The simplest curvaton scenario typically gives fNL≪-1 or fNL=+5/4. The inhomogeneous reheating scenario can give a wide range of values for fNL. Unless there is a detection, observation can eventually provide a limit |fNL|≲1, at which level it will be crucial to calculate the precise observational limit using second-order theory.
Second order perturbations during inflation beyond slow-roll
Huston, Ian; Malik, Karim A. E-mail: k.malik@qmul.ac.uk
2011-10-01
We numerically calculate the evolution of second order cosmological perturbations for an inflationary scalar field without resorting to the slow-roll approximation or assuming large scales. In contrast to previous approaches we therefore use the full non-slow-roll source term for the second order Klein-Gordon equation which is valid on all scales. The numerical results are consistent with the ones obtained previously where slow-roll is a good approximation. We investigate the effect of localised features in the scalar field potential which break slow-roll for some portion of the evolution. The numerical package solving the second order Klein-Gordon equation has been released under an open source license and is available for download.
Second-order perturbation theory: Problems on large scales
NASA Astrophysics Data System (ADS)
Pound, Adam
2015-11-01
In general-relativistic perturbation theory, a point mass accelerates away from geodesic motion due to its gravitational self-force. Because the self-force is small, one can often approximate the motion as geodesic. However, it is well known that self-force effects accumulate over time, making the geodesic approximation fail on long time scales. It is less well known that this failure at large times translates to a failure at large distances as well. At second perturbative order, two large-distance pathologies arise: spurious secular growth and infrared-divergent retarded integrals. Both stand in the way of practical computations of second-order self-force effects. Utilizing a simple flat-space scalar toy model, I develop methods to overcome these obstacles. The secular growth is tamed with a multiscale expansion that captures the system's slow evolution. The divergent integrals are eliminated by matching to the correct retarded solution at large distances. I also show how to extract conservative self-force effects by taking local-in-time "snapshots" of the global solution. These methods are readily adaptable to the physically relevant case of a point mass orbiting a black hole.
A new approach for second-order perturbation theory.
Tomlinson, David G; Asadchev, Andrey; Gordon, Mark S
2016-05-30
A new second-order perturbation theory (MP2) approach is presented for closed shell energy evaluations. The new algorithm has a significantly lower memory footprint, a lower FLOP (floating point operations) count, and a lower time to solution compared to previously implemented parallel MP2 methods in the GAMESS software package. Additionally, this algorithm features an adaptive approach for the disk/distributed memory storage of the MP2 amplitudes. The algorithm works well on a single workstation, small cluster, and large Cray cluster, and it allows one to perform large calculations with thousands of basis functions in a matter of hours on a single workstation. The same algorithm has been adapted for graphical processing unit (GPU) architecture. The performance of the new GPU algorithm is also discussed. © 2016 Wiley Periodicals, Inc. PMID:26940648
Second-order perturbative calculation of hydrogenic Zeeman levels
Chen, A.C.
1984-04-01
The degenerate perturbative treatment of the hydrogenic Zeeman problem is put on a more rigorous basis and is extended to higher levels belonging to the manifolds of M = n-Vertical BarmVertical Bar< or =4 basis states. The 16 n = 4 levels are calculated and the large-n behavior of the basis states is discussed.
Photonic Crystals from Order to Disorder: Perturbative Methods in Nanophotonics
Johnson, Steven G. [MIT, Cambridge, Massachusetts, United States
2010-01-08
Photonic crystals are periodic dielectric structures in which light can behave much differently than in a homogeneous medium. This talk gives an overview of some of the interesting properties and applications of these media, from switching in subwavelength microcavities to slow-light devices, to guiding light in air. However, some of the most interesting and challenging problems occur when the periodicity is disturbed, either by design or by inevitable fabrication imperfections. The talk focuses especially on small perturbations that have important effects, from slow-light tapers to surface roughness disorder, and will show that many classic perturbative approaches must be rethought for high-contrast nanophotonics. The combination of strong periodicity with large field discontinuities at interfaces causes standard methods to fail, but succumbs to new generalizations, while some problems remain open.
Automatic Integral Reduction for Higher Order Perturbative Calculations
Anastasiou, C
2004-06-04
We present a program for the reduction of large systems of integrals to master integrals. The algorithm was first proposed by Laporta; in this paper, we implement it in MAPLE. We also develop two new features which keep the size of intermediate expressions relatively small throughout the calculation. The program requires modest input information from the user and can be used for generic calculations in perturbation theory.
Application of MACSYMA to first order perturbation theory in celestial mechanics
NASA Technical Reports Server (NTRS)
Anderson, J. D.; Lau, E. L.
1977-01-01
The application of MACSYMA to general first order perturbation theory in celestial mechanics is explored. Methods of derivation of small variations in the Keplerian orbital elements are developed. As an example of the methods, the small general relativistic perturbations on the two-body Newtonian motion, resulting from the rotation of the central body, are developed in detail.
NASA Astrophysics Data System (ADS)
Reina, Borja; Vera, Raül
2015-08-01
Hartle's model describes the equilibrium configuration of a rotating isolated compact body in perturbation theory up to second order in general relativity. The interior of the body is a perfect fluid with a barotropic equation of state, no convective motions and rigid rotation. That interior is matched across its surface to an asymptotically flat vacuum exterior. Perturbations are taken to second order around a static and spherically symmetric background configuration. Apart from the explicit assumptions, the perturbed configuration is constructed upon some implicit premises, in particular the continuity of the functions describing the perturbation in terms of some background radial coordinate. In this work we revisit the model within a modern general and consistent theory of perturbative matchings to second order, which is independent of the coordinates and gauges used to describe the two regions to be joined. We explore the matching conditions up to second order in full. The main particular result we present is that the radial function m0 (in the setting of the original work) of the second order perturbation tensor, contrary to the original assumption, presents a jump at the surface of the star, which is proportional to the value of the energy density of the background configuration there. As a consequence, the change in mass δ M needed by the perturbed configuration to keep the value of the central energy density unchanged must be amended. We also discuss some subtleties that arise when studying the deformation of the star.
NASA Astrophysics Data System (ADS)
Nakamura, K.
2007-01-01
Following the general framework of the gauge invariant perturbation theory developed in the papers [K. Nakamura, Prog. Theor. Phys. 110 (2003), 723; ibid. 113 (2005), 481], we formulate second-order gauge invariant cosmological perturbation theory in a four-dimensional homogeneous isotropic universe. We consider perturbations both in the universe dominated by a single perfect fluid and in that dominated by a single scalar field. We derive all the components of the Einstein equations in the case that the first-order vector and tensor modes are negligible. All equations are derived in terms of gauge invariant variables without any gauge fixing. These equations imply that second-order vector and tensor modes may be generated due to the mode-mode coupling of the linear-order scalar perturbations. We also briefly discuss the main progress of this work through comparison with previous works.
Vector and tensor contributions to the curvature perturbation at second order
NASA Astrophysics Data System (ADS)
Carrilho, Pedro; Malik, Karim A.
2016-02-01
We derive the evolution equation for the second order curvature perturbation using standard techniques of cosmological perturbation theory. We do this for different definitions of the gauge invariant curvature perturbation, arising from different splits of the spatial metric, and compare the expressions. The results are valid at all scales and include all contributions from scalar, vector and tensor perturbations, as well as anisotropic stress, with all our results written purely in terms of gauge invariant quantities. Taking the large-scale approximation, we find that a conserved quantity exists only if, in addition to the non-adiabatic pressure, the transverse traceless part of the anisotropic stress tensor is also negligible. We also find that the version of the gauge invariant curvature perturbation which is exactly conserved is the one defined with the determinant of the spatial part of the inverse metric.
2nd Generation ELT Performance Specification Development
NASA Technical Reports Server (NTRS)
Stimson, Chad M.
2015-01-01
NASA Search And Rescue is supporting RTCA SC-229 with research and recommendations for performance specifications for the 2nd generation of emergency locator transmitters. Areas for improvement and methods for collecting data will be presented.
Next-to-leading order perturbative QCD corrections to baryon correlators in matter
Groote, S.; Koerner, J. G.; Pivovarov, A. A.
2008-08-01
We compute the next-to-leading order (NLO) perturbative QCD corrections to the correlators of nucleon interpolating currents in relativistic nuclear matter. The main new result is the calculation of the O({alpha}{sub s}) perturbative corrections to the coefficient functions of the vector quark condensate in matter. This condensate appears in matter due to the violation of Lorentz invariance. The NLO perturbative QCD corrections turn out to be large which implies that the NLO corrections must be included in a sum rule analysis of the properties of both bound nucleons and relativistic nuclear matter.
Laplace homotopy perturbation method for Burgers equation with space- and time-fractional order
NASA Astrophysics Data System (ADS)
Johnston, S. J.; Jafari, H.; Moshokoa, S. P.; Ariyan, V. M.; Baleanu, D.
2016-07-01
The fractional Burgers equation describes the physical processes of unidirectional propagation of weakly nonlinear acoustic waves through a gas-filled pipe. The Laplace homotopy perturbation method is discussed to obtain the approximate analytical solution of space-fractional and time-fractional Burgers equations. The method used combines the Laplace transform and the homotopy perturbation method. Numerical results show that the approach is easy to implement and accurate when applied to partial differential equations of fractional orders.
NASA Astrophysics Data System (ADS)
Dressler, John L.
1998-09-01
A method has been developed to drive a cylindrical liquid jet unstable for deformations with axial wavelengths shorter than the circumference of the jet and azimuthal mode numbers greater than 0. The benefit of this method is that a cylindrical liquid jet can be broken into a spray with an average diameter smaller than the diameter of the initial jet. The higher-order instabilities were created by establishing initial conditions for the jet in space and time at the nozzle. An electromechanical transducer creates the applied temporal initial condition which is a sinusoidally varying velocity perturbation added to the steady velocity of the jet. The amplitude of the velocity perturbation can be as large as the jet's steady velocity and the energy in the applied velocity perturbation drives the instability. The spatial perturbation is created by placing perturbations in the circumference of the nozzle. As the velocity perturbation travels on the jet, its leading edge steepens and the trailing edge broadens in a manner analogous to the steepening of a pressure pulse in a compressible gas. If the driven velocity perturbation is sufficiently large, a shock or jump forms on the leading edge of the velocity pulse and the jet may break up into higher-order modes. A theoretical analysis of the breakup process, based on an adaptation of compressible fluid shock theory, is used to derive a fundamental lower bound on the spray's Sauter mean diameter as a function of the velocity perturbation amplitude. Techniques for approaching the theoretical minimum spray diameter by using the higher-order modes to atomize liquid jets are discussed.
Determination of αs(Mτ2) from improved fixed order perturbation theory
NASA Astrophysics Data System (ADS)
Abbas, Gauhar; Ananthanarayan, B.; Caprini, Irinel
2012-05-01
We revisit the extraction of αs(Mτ2) from the QCD perturbative corrections to the hadronic τ branching ratio, using an improved fixed-order perturbation theory based on the explicit summation of all renormalization-group accessible logarithms, proposed some time ago in the literature. In this approach, the powers of the coupling in the expansion of the QCD Adler function are multiplied by a set of functions Dn, which depend themselves on the coupling and can be written in a closed form by iteratively solving a sequence of differential equations. We find that the new expansion has an improved behavior in the complex energy plane compared to that of the standard fixed-order perturbation theory (FOPT), and is similar but not identical to the contour-improved perturbation theory (CIPT). With five terms in the perturbative expansion we obtain in the MS¯ scheme αs(Mτ2)=0.338±0.010, using as input a precise value for the perturbative contribution to the hadronic width of the τ lepton reported recently in the literature.
Consistency of Equations in the Second-Order Gauge-Invariant Cosmological Perturbation Theory
NASA Astrophysics Data System (ADS)
Nakamura, K.
2009-06-01
Along the general framework of the gauge-invariant perturbation theory developed in the papers [K.~Nakamura, Prog.~Theor.~Phys. 110 (2003), 723; Prog.~Theor.~Phys. 113 (2005), 481], we rederive the second-order Einstein equation on four-dimensional homogeneous isotropic background universe in a gauge-invariant manner without ignoring any mode of perturbations. We consider the perturbations both in the universe dominated by the single perfect fluid and in that dominated by the single scalar field. We also confirmed the consistency of all the equations of the second-order Einstein equation and the equations of motion for matter fields, which are derived in the paper [K.~Nakamura, arXiv:0804.3840]. This confirmation implies that all the derived equations of the second order are self-consistent and these equations are correct in this sense.
Mehl, James B.
2007-01-01
The boundary-shape formalism of Morse and Ingard is applied to the acoustic modes of a deformed spherical resonator (quasisphere) with rigid boundaries. For boundary shapes described by r = a [1 − ε ℱ(θ, ϕ)], where ε is a small scale parameter and ℱ is a function of order unity, the frequency perturbation is calculated to order ε2. The formal results apply to acoustic modes whose angular dependence is designated by the indices ℓ and m. Specific examples are worked out for the radial (ℓ = 0) and triplet (ℓ = 1) modes, for prolate and oblate spheroids, and for triaxial ellipsoids. The exact eigenvalues for the spheroids, and eigenvalue determined with finite-element calculations, are shown to agree with perturbation theory through terms of order ε2. This work is an extension of the author’s previous papers on the acoustic eigenfrequencies of deformed spherical resonators, which were limited to the second-order perturbation for radial modes [J. Acoust. Soc. Am. 71, 1109-1113 (1982)] and the first order-perturbation for arbitrary modes [J. Acoust. Soc. Am. 79, 278–285 (1986)]. PMID:27110463
Action approach to cosmological perturbations: the second-order metric in matter dominance
Boubekeur, Lotfi; Creminelli, Paolo; Vernizzi, Filippo; Norena, Jorge
2008-08-15
We study nonlinear cosmological perturbations during post-inflationary evolution, using the equivalence between a perfect barotropic fluid and a derivatively coupled scalar field with Lagrangian [-({partial_derivative}{phi}){sup 2}]{sup (1+w)/2w}. Since this Lagrangian is just a special case of k-inflation, this approach is analogous to the one employed in the study of non-Gaussianities from inflation. We use this method to derive the second-order metric during matter dominance in the comoving gauge directly as a function of the primordial inflationary perturbation {zeta}. Going to Poisson gauge, we recover the metric previously derived in the literature.
The effect of problem perturbations on nonlinear dynamical systems and their reduced order models
Serban, R; Homescu, C; Petzold, L
2005-03-03
Reduced order models are used extensively in many areas of science and engineering for simulation, design, and control. Reduction techniques for nonlinear dynamical systems produce models that depend strongly on the nominal set of parameters for which the reduction is carried out. In this paper we address the following two questions: 'What is the effect of perturbations in the problem parameters on the output functional of a nonlinear dynamical system?' and 'To what extent does the reduced order model capture this effect?'
Self-consistent second-order Green's function perturbation theory for periodic systems
NASA Astrophysics Data System (ADS)
Rusakov, Alexander A.; Zgid, Dominika
2016-02-01
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear as promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function (GF2) method, where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in k-space are the key components of a computationally feasible algorithm. We apply this technique to the one-dimensional hydrogen lattice — a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases.
PIRLS 2016 Assessment Framework. 2nd Edition
ERIC Educational Resources Information Center
Mullis, Ina V. S., Ed.; Martin, Michael O., Ed.
2015-01-01
The "PIRLS 2016 Assessment Framework, 2nd Edition" provides the foundation for the three international assessments planned as part of the International Association for the Evaluation of Educational Achievement's Progress in International Reading Literacy Study (PIRLS) 2016: PIRLS, PIRLS Literacy, and ePIRLS. PIRLS represents the…
Exploring arbitrarily high orders of optimized perturbation theory in QCD with nf → 161/2
NASA Astrophysics Data System (ADS)
Stevenson, P. M.
2016-09-01
Perturbative QCD with nf flavours of massless quarks becomes simple in the hypothetical limit nf → 161/2, where the leading β-function coefficient vanishes. The Banks-Zaks (BZ) expansion in a0 ≡8/321 (161/2 -nf) is straightforward to obtain from perturbative results in MS ‾ or any renormalization scheme (RS) whose nf dependence is 'regular'. However, 'irregular' RS's are perfectly permissible and should ultimately lead to the same BZ results. We show here that the 'optimal' RS determined by the Principle of Minimal Sensitivity does yield the same BZ-expansion results when all orders of perturbation theory are taken into account. The BZ limit provides an arena for exploring optimized perturbation theory at arbitrarily high orders. These explorations are facilitated by a 'master equation' expressing the optimization conditions in the fixed-point limit. We find an intriguing strong/weak coupling duality a →a*2 / a about the fixed point a*.
NASA Technical Reports Server (NTRS)
Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)
1994-01-01
A new approach to perturbation theory based on a CASSCF reference function has been developed. The key to the approach is the definition of the zeroth order Hamiltonian, H(sub 0), which includes the full CI Hamiltonian for the active space. In the the inactive and secondary spaces, operators may be chosen which reduce to the usual Moller-Plesset or Epstein-Nesbet forms in the limit of a null active space. These operators are diagonal in the orbital indices and permit the block-diagonalization of H(sub 0). The reference is an eigenfunction of Ho without N-particle projection. H(sub 0) automatically incorporates denominator shifts in the style of those appearing in recent open-shell perturbation theories. Comparative results are presented for a few test cases.
NASA Astrophysics Data System (ADS)
Kéchichian, Jean A.
2011-09-01
A fourth order extension of the analytic form of the accelerations due to the luni-solar gravity perturbations along rotating axes is presented. These derivations are carried out in order to increase the accuracy of the dynamic modeling of perturbed optimal low-thrust transfers between general elliptic orbits, and enhance the fidelity of trajectory optimization software used in simulations and mission analyses. A set of rotating axes attached to the thrusting spacecraft is used such that both the thrust and perturbation accelerations due to Earth's geopotential and the luni-solar gravity are mathematically resolved along these axes prior to numerical integration of the actual trajectory. This Gaussian form of the state as well as the adjoint differential equations form a set of equations that are readily integrated and an iterative process is used to achieve convergence to a desired transfer. This analysis further reveals that further extensions to higher orders, say to the fifth order and beyond, are not needed to extract even more accuracy in the solutions because the minimum-time transfer solutions become fully stabilized in the sense that they do not exhibit any differences beyond a fraction of a second, or at most a few seconds even in the more extreme cases of very large orbits with apogee heights around 100,000 km with strong lunar influence.
NASA Astrophysics Data System (ADS)
Deniz, Sinan; Bildik, Necdet
2016-06-01
In this paper, we use Adomian Decomposition Method (ADM) to solve the singularly perturbed fourth order boundary value problem. In order to make the calculation process easier, first the given problem is transformed into a system of two second order ODEs, with suitable boundary conditions. Numerical illustrations are given to prove the effectiveness and applicability of this method in solving these kinds of problems. Obtained results shows that this technique provides a sequence of functions which converges rapidly to the accurate solution of the problems.
Fourth order solutions of singularly perturbed boundary value problems by quarter-sweep iteration
NASA Astrophysics Data System (ADS)
Sulaiman, J.; Hasan, M. K.; Othman, M.; Abdul Karim, S. A.
2013-04-01
In previous studies, the effectiveness of the second-order quarter-sweep finite difference approximation equations has been shown in solving singularly perturbed boundary value problems. In this paper, however, we investigate the application of the fourth-order quarter-sweep finite difference approximation equation based on the fourth-order standard central difference scheme. To solve the problems numerically, discretization of the singularly perturbed problems via second-order and fourth-order finite difference schemes is proposed to form the corresponding system of linear algebraic equations. For comparison purpose, we also discuss on how to derive the basic formulation and implementation for the family of Successive Over-Relaxation (SOR) iterative methods such as FSSOR, HSSOR and QSSOR in solving the corresponding linear systems generated from the fourth-order discretization schemes based on full, half- and quarter-sweep cases. Some numerical tests were conducted to show that the accuracy of fourth-order finite difference schemes via the corresponding GS methods is more accurate than second-order schemes.
Axion as a cold dark matter candidate: analysis to third order perturbation for classical axion
NASA Astrophysics Data System (ADS)
Noh, Hyerim; Hwang, Jai-chan; Park, Chan-Gyung
2015-12-01
We investigate aspects of axion as a coherently oscillating massive classical scalar field by analyzing third order perturbations in Einstein's gravity in the axion-comoving gauge. The axion fluid has its characteristic pressure term leading to an axion Jeans scale which is cosmologically negligible for a canonical axion mass. Our classically derived axion pressure term in Einstein's gravity is identical to the one derived in the non-relativistic quantum mechanical context in the literature. We present the general relativistic continuity and Euler equations for an axion fluid valid up to third order perturbation. Equations for axion are exactly the same as that of a zero-pressure fluid in Einstein's gravity except for an axion pressure term in the Euler equation. Our analysis includes the cosmological constant.
Sahoo, Tapas; Pollak, Eli
2015-08-14
A second order classical perturbation theory is developed to calculate the sticking probability of a particle scattered from an uncorrugated thermal surface. An analytic expression for the temperature dependent energy loss of the particle to the surface is derived by employing a one-dimensional generalized Langevin equation. The surface temperature reduces the energy loss, since the thermal surface transfers energy to the particle. Using a Gaussian energy loss kernel and the multiple collision theory of Fan and Manson [J. Chem. Phys. 130, 064703 (2009)], enables the determination of the fraction of particles trapped on the surface after subsequent momentum reversals of the colliding particle. This then leads to an estimate of the trapping probability. The theory is tested for the model scattering of Ar on a LiF(100) surface. Comparison with numerical simulations shows excellent agreement of the analytical theory with simulations, provided that the energy loss is determined by the second order perturbation theory.
Second-Order Perturbation Theory for Generalized Active Space Self-Consistent-Field Wave Functions.
Ma, Dongxia; Li Manni, Giovanni; Olsen, Jeppe; Gagliardi, Laura
2016-07-12
A multireference second-order perturbation theory approach based on the generalized active space self-consistent-field (GASSCF) wave function is presented. Compared with the complete active space (CAS) and restricted active space (RAS) wave functions, GAS wave functions are more flexible and can employ larger active spaces and/or different truncations of the configuration interaction expansion. With GASSCF, one can explore chemical systems that are not affordable with either CASSCF or RASSCF. Perturbation theory to second order on top of GAS wave functions (GASPT2) has been implemented to recover the remaining electron correlation. The method has been benchmarked by computing the chromium dimer ground-state potential energy curve. These calculations show that GASPT2 gives results similar to CASPT2 even with a configuration interaction expansion much smaller than the corresponding CAS expansion. PMID:27276688
Relativistic corrections to electrical first-order properties using direct perturbation theory.
Stopkowicz, Stella; Gauss, Jürgen
2008-10-28
Direct perturbation theory (DPT) is applied to compute relativistic corrections to electrical properties such as dipole moment, quadrupole moment, and electric-field gradient. The corrections are obtained as second derivatives of the energy and are given via method-independent expressions that involve the first derivative of the density matrix with respect to the relativistic perturbation as well as property integrals with additional momentum operators. Computational results obtained using Hartree-Fock (HF), second-order Moller-Plesset (MP2) perturbation theory, and the coupled-cluster singles and doubles approach augmented by a perturbative treatment of triple excitations are presented for the hydrogen halides HX with X=F, Cl, Br, (I, At) and the magnitude of relativistic effects, their basis-set dependence, and the limitations of DPT are discussed. We compare our results to those obtained using the second-order Douglas-Kroll method and benchmark them using four-component HF (Dirac-HF) and MP2 calculations. Relativistic effects are shown to be already important for elements of the third row (Na-Ar) when aiming at a high-accuracy quantum-chemical treatment. DPT provides reliable results for compounds containing elements up to the fourth period (K-Kr) and only breaks down when applied in lowest order to heavier elements. As a first application of the present DPT treatment for electrical properties, we report calculations for bromofluoromethane (CH(2)FBr) which was investigated using rotational spectroscopy by Cazzoli et al. [Mol. Phys. 106, 1181 (2008)] and for which consideration of relativistic effects turns out to be essential for good agreement between theory and experiment in the case of the bromine quadrupole-coupling constant. PMID:19045259
2nd & 3rd Generation Vehicle Subsystems
NASA Technical Reports Server (NTRS)
2000-01-01
This paper contains viewgraph presentation on the "2nd & 3rd Generation Vehicle Subsystems" project. The objective behind this project is to design, develop and test advanced avionics, power systems, power control and distribution components and subsystems for insertion into a highly reliable and low-cost system for a Reusable Launch Vehicles (RLV). The project is divided into two sections: 3rd Generation Vehicle Subsystems and 2nd Generation Vehicle Subsystems. The following topics are discussed under the first section, 3rd Generation Vehicle Subsystems: supporting the NASA RLV program; high-performance guidance & control adaptation for future RLVs; Evolvable Hardware (EHW) for 3rd generation avionics description; Scaleable, Fault-tolerant Intelligent Network or X(trans)ducers (SFINIX); advance electric actuation devices and subsystem technology; hybrid power sources and regeneration technology for electric actuators; and intelligent internal thermal control. Topics discussed in the 2nd Generation Vehicle Subsystems program include: design, development and test of a robust, low-maintenance avionics with no active cooling requirements and autonomous rendezvous and docking systems; design and development of a low maintenance, high reliability, intelligent power systems (fuel cells and battery); and design of a low cost, low maintenance high horsepower actuation systems (actuators).
Efficient configuration selection scheme for vibrational second-order perturbation theory
NASA Astrophysics Data System (ADS)
Yagi, Kiyoshi; Hirata, So; Hirao, Kimihiko
2007-07-01
A fast algorithm of vibrational second-order Møller-Plesset perturbation theory is proposed, enabling a substantial reduction in the number of vibrational self-consistent-field (VSCF) configurations that need to be summed in the calculations. Important configurations are identified a priori by assuming that a reference VSCF wave function is approximated well by harmonic oscillator wave functions and that fifth- and higher-order anharmonicities are negligible. The proposed scheme has reduced the number of VSCF configurations by more than 100 times for formaldehyde, ethylene, and furazan with an error in computed frequencies being not more than a few cm-1.
Efficient configuration selection scheme for vibrational second-order perturbation theory.
Yagi, Kiyoshi; Hirata, So; Hirao, Kimihiko
2007-07-21
A fast algorithm of vibrational second-order Moller-Plesset perturbation theory is proposed, enabling a substantial reduction in the number of vibrational self-consistent-field (VSCF) configurations that need to be summed in the calculations. Important configurations are identified a priori by assuming that a reference VSCF wave function is approximated well by harmonic oscillator wave functions and that fifth- and higher-order anharmonicities are negligible. The proposed scheme has reduced the number of VSCF configurations by more than 100 times for formaldehyde, ethylene, and furazan with an error in computed frequencies being not more than a few cm(-1). PMID:17655435
First-order Cosmological Perturbations Engendered by Point-like Masses
NASA Astrophysics Data System (ADS)
Eingorn, Maxim
2016-07-01
In the framework of the concordance cosmological model, the first-order scalar and vector perturbations of the homogeneous background are derived in the weak gravitational field limit without any supplementary approximations. The sources of these perturbations (inhomogeneities) are presented in the discrete form of a system of separate point-like gravitating masses. The expressions found for the metric corrections are valid at all (sub-horizon and super-horizon) scales and converge at all points except at the locations of the sources. The average values of these metric corrections are zero (thus, first-order backreaction effects are absent). Both the Minkowski background limit and the Newtonian cosmological approximation are reached under certain well-defined conditions. An important feature of the velocity-independent part of the scalar perturbation is revealed: up to an additive constant, this part represents a sum of Yukawa potentials produced by inhomogeneities with the same finite time-dependent Yukawa interaction range. The suggested connection between this range and the homogeneity scale is briefly discussed along with other possible physical implications.
Lagrangian perturbations and the matter bispectrum I: fourth-order model for non-linear clustering
Rampf, Cornelius; Buchert, Thomas E-mail: buchert@obs.univ-lyon1.fr
2012-06-01
We investigate the Lagrangian perturbation theory of a homogeneous and isotropic universe in the non-relativistic limit, and derive the solutions up to the fourth order. These solutions are needed for example for the next-to-leading order correction of the (resummed) Lagrangian matter bispectrum, which we study in an accompanying paper. We focus on flat cosmologies with a vanishing cosmological constant, and provide an in-depth description of two complementary approaches used in the current literature. Both approaches are solved with two different sets of initial conditions — both appropriate for modelling the large-scale structure. Afterwards we consider only the fastest growing mode solution, which is not affected by either of these choices of initial conditions. Under the reasonable approximation that the linear density contrast is evaluated at the initial Lagrangian position of the fluid particle, we obtain the nth-order displacement field in the so-called initial position limit: the nth order displacement field consists of 3(n-1) integrals over n linear density contrasts, and obeys self-similarity. Then, we find exact relations between the series in Lagrangian and Eulerian perturbation theory, leading to identical predictions for the density contrast and the peculiar-velocity divergence up to the fourth order.
Testing higher-order Lagrangian perturbation theory against numerical simulation. 1: Pancake models
NASA Technical Reports Server (NTRS)
Buchert, T.; Melott, A. L.; Weiss, A. G.
1993-01-01
We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of quasi-linear scales. The Lagrangian theory of gravitational instability of an Einstein-de Sitter dust cosmogony investigated and solved up to the third order is compared with numerical simulations. In this paper we study the dynamics of pancake models as a first step. In previous work the accuracy of several analytical approximations for the modeling of large-scale structure in the mildly non-linear regime was analyzed in the same way, allowing for direct comparison of the accuracy of various approximations. In particular, the Zel'dovich approximation (hereafter ZA) as a subclass of the first-order Lagrangian perturbation solutions was found to provide an excellent approximation to the density field in the mildly non-linear regime (i.e. up to a linear r.m.s. density contrast of sigma is approximately 2). The performance of ZA in hierarchical clustering models can be greatly improved by truncating the initial power spectrum (smoothing the initial data). We here explore whether this approximation can be further improved with higher-order corrections in the displacement mapping from homogeneity. We study a single pancake model (truncated power-spectrum with power-spectrum with power-index n = -1) using cross-correlation statistics employed in previous work. We found that for all statistical methods used the higher-order corrections improve the results obtained for the first-order solution up to the stage when sigma (linear theory) is approximately 1. While this improvement can be seen for all spatial scales, later stages retain this feature only above a certain scale which is increasing with time. However, third-order is not much improvement over second-order at any stage. The total breakdown of the perturbation approach is observed at the stage, where sigma (linear theory) is approximately 2, which corresponds to the
Photoassociation of a cold-atom-molecule pair. II. Second-order perturbation approach
Lepers, M.; Vexiau, R.; Bouloufa, N.; Dulieu, O.; Kokoouline, V.
2011-04-15
The electrostatic interaction between an excited atom and a diatomic ground-state molecule in an arbitrary rovibrational level at large mutual separations is investigated with a general second-order perturbation theory, in the perspective of modeling the photoassociation between cold atoms and molecules. We find that the combination of quadrupole-quadrupole and van der Waals interactions competes with the rotational energy of the dimer, limiting the range of validity of the perturbative approach to distances larger than 100 Bohr radii. Numerical results are given for the long-range interaction between Cs and Cs{sub 2}, showing that the photoassociation is probably efficient for any Cs{sub 2} rotational energy.
NASA Astrophysics Data System (ADS)
Alles, Alexandre; Buchert, Thomas; Al Roumi, Fosca; Wiegand, Alexander
2015-07-01
The relativistic generalization of the Newtonian Lagrangian perturbation theory is investigated. In previous works, the first-order trace solutions that are generated by the spatially projected gravitoelectric part of the Weyl tensor were given together with extensions and applications for accessing the nonperturbative regime. We furnish here construction rules to obtain from Newtonian solutions the gravitoelectric class of relativistic solutions, for which we give the complete perturbation and solution schemes at any order of the perturbations. By construction, these schemes generalize the complete hierarchy of solutions of the Newtonian Lagrangian perturbation theory.
High-order terms in the renormalized perturbation theory for the Anderson impurity model
NASA Astrophysics Data System (ADS)
Pandis, Vassilis; Hewson, Alex C.
2015-09-01
We study the renormalized perturbation theory of the single-impurity Anderson model, particularly the high-order terms in the expansion of the self-energy in powers of the renormalized coupling U ˜. Though the presence of counterterms in the renormalized theory may appear to complicate the diagrammatics, we show how these can be seamlessly accommodated by carrying out the calculation order-by-order in terms of skeleton diagrams. We describe how the diagrams pertinent to the renormalized self-energy and four vertex can be automatically generated, translated into integrals, and numerically integrated. To maximize the efficiency of our approach we introduce a generalized k -particle/hole propagator, which is used to analytically simplify the resultant integrals and reduce the dimensionality of the integration. We present results for the self-energy and spectral density to fifth order in U ˜, for various values of the model asymmetry, and compare them to a numerical renormalization group calculation.
MULTIPOLE GRAVITATIONAL LENSING AND HIGH-ORDER PERTURBATIONS ON THE QUADRUPOLE LENS
Chu, Z.; Lin, W. P.; Li, G. L.; Kang, X. E-mail: linwp@shao.ac.cn
2013-03-10
An arbitrary surface mass density of the gravitational lens can be decomposed into multipole components. We simulate the ray tracing for the multipolar mass distribution of the generalized Singular Isothermal Sphere model based on deflection angles, which are analytically calculated. The magnification patterns in the source plane are then derived from an inverse shooting technique. As has been found, the caustics of odd mode lenses are composed of two overlapping layers for some lens models. When a point source traverses this kind of overlapping caustics, the image numbers change by {+-}4, rather than {+-}2. There are two kinds of caustic images. One is the critical curve and the other is the transition locus. It is found that the image number of the fold is exactly the average value of image numbers on two sides of the fold, while the image number of the cusp is equal to the smaller one. We also focus on the magnification patterns of the quadrupole (m = 2) lenses under the perturbations of m = 3, 4, and 5 mode components and found that one, two, and three butterfly or swallowtail singularities can be produced, respectively. With the increasing intensity of the high-order perturbations, the singularities grow up to bring sixfold image regions. If these perturbations are large enough to let two or three of the butterflies or swallowtails make contact, then eightfold or tenfold image regions can be produced as well. The possible astronomical applications are discussed.
Macroscopic order in a nematic liquid crystal: Perturbation by spontaneous director fluctuations.
Hamasuna, Daichi; Hashim, Rauzah; Kasatani, Atsuhiro; Luckhurst, Geoffrey R; Sugimura, Akihiko; Timimi, Bakir A; Zimmermann, Herbert
2015-06-01
The dynamic alignment of the nematic director by near-orthogonal electric and magnetic fields has been investigated. The intermediate states during the relaxation process were found, with the aid of time-resolved deuterium NMR spectroscopy, to be markedly nonuniform. The macroscopic order was perturbed, although the initial and final states of the director appear to be essentially uniform. However, the initial state does have a profound influence on the uniformity of the director in the intermediate states. We have developed a fundamental model based on the effect of spontaneous director fluctuations to explain these unusual NMR observations. PMID:26172726
Process-chain approach to high-order perturbation calculus for quantum lattice models
Eckardt, Andre
2009-05-15
A method based on Rayleigh-Schroedinger perturbation theory is developed that allows to obtain high-order series expansions for ground-state properties of quantum lattice models. The approach is capable of treating both lattice geometries of large spatial dimensionalities d and on-site degrees of freedom with large state space dimensionalities. It has recently been used to accurately compute the zero-temperature phase diagram of the Bose-Hubbard model on a hypercubic lattice, up to arbitrary large filling and for d=2, 3, and greater [Teichmann et al., Phys. Rev. B 79, 100503(R) (2009)].0.
Bifurcation and chaos in a perturbed soliton equation with higher-order nonlinearity
NASA Astrophysics Data System (ADS)
Yu, Jun; Zhang, Rongbo; Jin, Guojuan
2011-12-01
The influence of a soliton system under external perturbation is considered. We take the compound Korteweg-de Vries-Burgers-type equation with nonlinear terms of any order as an example, and investigate numerically the chaotic behavior of the system with periodic forcing. It is shown that dynamical chaos can occur when we appropriately choose system parameters. Abundant bifurcation structures and different routes to chaos, such as period doubling, intermittent bifurcation and crisis, are found by applying bifurcation diagrams, Poincaré maps and phase portraits. To characterize the chaotic behavior of this system, a spectrum of Lyapunov exponents and Lyapunov dimensions of attractors are also employed.
Ten-no, Seiichiro; Yamaki, Daisuke
2012-10-01
We propose explicitly correlated Ansatz for four-component relativistic methods within the framework of the no-pair approximation. Kinetically balanced geminal basis is derived to satisfy the cusp conditions in the non-relativistic limit based on the Lévy-Leblend-like equation. Relativistic variants of strong-orthogonality projection operator (Ansätze 2α and 2β) suitable for practical calculations are introduced by exploiting the orthogonal complement of the large-component basis. A pilot implementation is performed for the second order Møller-Plesset perturbation theory. PMID:23039576
Block correlated second order perturbation theory with a generalized valence bond reference function
Xu, Enhua; Li, Shuhua
2013-11-07
The block correlated second-order perturbation theory with a generalized valence bond (GVB) reference (GVB-BCPT2) is proposed. In this approach, each geminal in the GVB reference is considered as a “multi-orbital” block (a subset of spin orbitals), and each occupied or virtual spin orbital is also taken as a single block. The zeroth-order Hamiltonian is set to be the summation of the individual Hamiltonians of all blocks (with explicit two-electron operators within each geminal) so that the GVB reference function and all excited configuration functions are its eigenfunctions. The GVB-BCPT2 energy can be directly obtained without iteration, just like the second order Møller–Plesset perturbation method (MP2), both of which are size consistent. We have applied this GVB-BCPT2 method to investigate the equilibrium distances and spectroscopic constants of 7 diatomic molecules, conformational energy differences of 8 small molecules, and bond-breaking potential energy profiles in 3 systems. GVB-BCPT2 is demonstrated to have noticeably better performance than MP2 for systems with significant multi-reference character, and provide reasonably accurate results for some systems with large active spaces, which are beyond the capability of all CASSCF-based methods.
First order perturbations of the Einstein-Straus and Oppenheimer-Snyder models
Mars, Marc; Mena, Filipe C.; Vera, Rauel
2008-10-15
We derive the linearly perturbed matching conditions between a Schwarzschild spacetime region with stationary and axially symmetric perturbations and a Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime with arbitrary perturbations. The matching hypersurface is also perturbed arbitrarily and, in all cases, the perturbations are decomposed into scalars using the Hodge operator on the sphere. This allows us to write down the matching conditions in a compact way. In particular, we find that the existence of a perturbed (rotating, stationary, and vacuum) Schwarzschild cavity in a perturbed FLRW universe forces the cosmological perturbations to satisfy constraints that link rotational and gravitational wave perturbations. We also prove that if the perturbation on the FLRW side vanishes identically, then the vacuole must be perturbatively static and hence Schwarzschild. By the dual nature of the problem, the first result translates into links between rotational and gravitational wave perturbations on a perturbed Oppenheimer-Snyder model, where the perturbed FLRW dust collapses in a perturbed Schwarzschild environment which rotates in equilibrium. The second result implies, in particular, that no region described by FLRW can be a source of the Kerr metric.
First order perturbations of the Einstein-Straus and Oppenheimer-Snyder models
NASA Astrophysics Data System (ADS)
Mars, Marc; Mena, Filipe C.; Vera, Raül
2008-10-01
We derive the linearly perturbed matching conditions between a Schwarzschild spacetime region with stationary and axially symmetric perturbations and a Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime with arbitrary perturbations. The matching hypersurface is also perturbed arbitrarily and, in all cases, the perturbations are decomposed into scalars using the Hodge operator on the sphere. This allows us to write down the matching conditions in a compact way. In particular, we find that the existence of a perturbed (rotating, stationary, and vacuum) Schwarzschild cavity in a perturbed FLRW universe forces the cosmological perturbations to satisfy constraints that link rotational and gravitational wave perturbations. We also prove that if the perturbation on the FLRW side vanishes identically, then the vacuole must be perturbatively static and hence Schwarzschild. By the dual nature of the problem, the first result translates into links between rotational and gravitational wave perturbations on a perturbed Oppenheimer-Snyder model, where the perturbed FLRW dust collapses in a perturbed Schwarzschild environment which rotates in equilibrium. The second result implies, in particular, that no region described by FLRW can be a source of the Kerr metric.
NASA Astrophysics Data System (ADS)
Shefer, V. A.
2006-12-01
The theory of superosculating intermediate orbits previously suggested by the author is developed. A new class of orbits with a fourth-order tangency to the actual trajectory of a celestial body at the initial time is constructed. Orbits with a fifth-order tangency have been constructed for the first time. The motion in the constructed orbits is represented as a combination of two motions: the motion of a fictitious attracting center with a variable mass and the motion relative to this center. The first motion is generally parabolic, while the second motion is described by the equations of the Gylden—Mestschersky problem. The variation in the mass of the fictitious center obeys Mestschersky’s first and combined laws. The new orbits represent more accurately the actual motion in the initial segment of the trajectory than an osculating Keplerian orbit and other existing analogues. Encke’s generalized methods of special perturbations in which the constructed intermediate orbits are used as reference orbits are presented. Numerical simulations using the approximations of the motions of Asteroid Toutatis and Comet P/Honda—Mrkos—Pajdušáková as examples confirm that the constructed orbits are highly efficient. Their application is particularly beneficial in investigating strongly perturbed motion.
Quasidegenerate second-order perturbation corrections to single excitation configuration interaction
NASA Astrophysics Data System (ADS)
Head-Gordon, Martin
1999-02-01
A family of quasidegenerate second-order perturbation theories that correct excitation energies from single-excitation configuration interaction (CIS) are introduced which generalize the earlier non-degenerate second-order method, CIS(D). The new methods are termed CIS(D), where n ranges from 0 to x, according to the number of terms retained in a doubles denominator expansion. Truncation at either n = 0 or n = 1 yields methods which involve the diagonalization of a dressed singles-only response matrix, where the dressing is state-independent. Hence CIS(D0) and CIS(D1) can be implemented efficiently using semidirect methods, which are discussed. Test calculations on formaldehyde, ethylene, chlorine nitrate, styrene, benzaldehyde, and chalcone are presented to assess the performance of these methods. CIS(D0) and CIS(D1) both show significant improvements relative to CIS(D) in cases of near-degeneracy.
NASA Astrophysics Data System (ADS)
Ren, Xinguo; Rinke, Patrick; Scuseria, Gustavo E.; Scheffler, Matthias
2013-07-01
We present a renormalized second-order perturbation theory (rPT2), based on a Kohn-Sham (KS) reference state, for the electron correlation energy that includes the random-phase approximation (RPA), second-order screened exchange (SOSEX), and renormalized single excitations (rSE). These three terms all involve a summation of certain types of diagrams to infinite order, and can be viewed as ``renormalization'' of the second-order direct, exchange, and single-excitation (SE) terms of Rayleigh-Schrödinger perturbation theory based on a KS reference. In this work, we establish the concept of rPT2 and present the numerical details of our SOSEX and rSE implementations. A preliminary version of rPT2, in which the renormalized SE (rSE) contribution was treated approximately, has already been benchmarked for molecular atomization energies and chemical reaction barrier heights and shows a well-balanced performance [J. Paier , New J. Phys.1367-263010.1088/1367-2630/14/4/043002 14, 043002 (2012)]. In this work, we present a refined version of rPT2, in which we evaluate the rSE series of diagrams rigorously. We then extend the benchmark studies to noncovalent interactions, including the rare-gas dimers, and the S22 and S66 test sets, as well as the cohesive energy of small copper clusters, and the equilibrium geometry of 10 diatomic molecules. Despite some remaining shortcomings, we conclude that rPT2 gives an overall satisfactory performance across different electronic situations, and is a promising step towards a generally applicable electronic-structure approach.
Nonlinear waves in second order conformal hydrodynamics
NASA Astrophysics Data System (ADS)
Fogaça, D. A.; Marrochio, H.; Navarra, F. S.; Noronha, J.
2015-02-01
In this work we study wave propagation in dissipative relativistic fluids described by a simplified set of the 2nd order viscous conformal hydrodynamic equations corresponding to Israel-Stewart theory. Small amplitude waves are studied within the linearization approximation while waves with large amplitude are investigated using the reductive perturbation method, which is generalized to the case of 2nd order relativistic hydrodynamics. Our results indicate the presence of a "soliton-like" wave solution in Israel-Stewart hydrodynamics despite the presence of dissipation and relaxation effects.
NASA Astrophysics Data System (ADS)
Casanova, David; Rhee, Young Min; Head-Gordon, Martin
2008-04-01
Scaled opposite spin (SOS) second order perturbative corrections to single excitation configuration interaction (CIS) are extended to correctly treat quasidegeneracies between excited states. Two viable methods, termed as SOS-CIS(D0) and SOS-CIS(D1), are defined, implemented, and tested. Each involves one empirical parameter (plus a second for the SOS-MP2 ground state), has computational cost that scales with the fourth power of molecule size, and has storage requirements that are cubic, with only quantities of the rank of single excitations produced and stored during iterations. Tests on a set of low-lying adiabatic valence excitation energies and vertical Rydberg excitations of organic and inorganic molecules show that the empirical parameter can be acceptably transferred from the corresponding nondegenerate perturbation theories without any further fitting. Further tests on higher excited states show that the new methods correctly perform for surface crossings for which nondegenerate approaches fail. Numerical results show that SOS-CIS(D0) appears to treat Rydberg excitations in a more balanced way than SOS-CIS(D1) and is, therefore, likely to be the preferred approach. It should be useful for exploring excited state geometries, transition structures, and conical intersections for states of medium to large organic molecules that are dominated by single excitations.
2nd Generation RLV Risk Definition Program
NASA Technical Reports Server (NTRS)
Davis, Robert M.; Stucker, Mark (Technical Monitor)
2000-01-01
The 2nd Generation RLV Risk Reduction Mid-Term Report summarizes the status of Kelly Space & Technology's activities during the first two and one half months of the program. This report was presented to the cognoscente Contracting Officer's Technical Representative (COTR) and selected Marshall Space Flight Center staff members on 26 September 2000. The report has been approved and is distributed on CD-ROM (as a PowerPoint file) in accordance with the terms of the subject contract, and contains information and data addressing the following: (1) Launch services demand and requirements; (2) Architecture, alternatives, and requirements; (3) Costs, pricing, and business cases analysis; (4) Commercial financing requirements, plans, and strategy; (5) System engineering processes and derived requirements; and (6) RLV system trade studies and design analysis.
2nd International Planetary Probe Workshop
NASA Technical Reports Server (NTRS)
Venkatapathy, Ethiraj; Martinez, Ed; Arcadi, Marla
2005-01-01
Included are presentations from the 2nd International Planetary Probe Workshop. The purpose of the second workshop was to continue to unite the community of planetary scientists, spacecraft engineers and mission designers and planners; whose expertise, experience and interests are in the areas of entry probe trajectory and attitude determination, and the aerodynamics/aerothermodynamics of planetary entry vehicles. Mars lander missions and the first probe mission to Titan made 2004 an exciting year for planetary exploration. The Workshop addressed entry probe science, engineering challenges, mission design and instruments, along with the challenges of reconstruction of the entry, descent and landing or the aerocapture phases. Topics addressed included methods, technologies, and algorithms currently employed; techniques and results from the rich history of entry probe science such as PAET, Venera/Vega, Pioneer Venus, Viking, Galileo, Mars Pathfinder and Mars MER; upcoming missions such as the imminent entry of Huygens and future Mars entry probes; and new and novel instrumentation and methodologies.
NASA Astrophysics Data System (ADS)
Abbas, Gauhar; Ananthanarayan, B.; Caprini, Irinel; Fischer, Jan
2013-08-01
The moments of the hadronic spectral functions are of interest for the extraction of the strong coupling αs and other QCD parameters from the hadronic decays of the τ lepton. Motivated by the recent analyses of a large class of moments in the standard fixed-order and contour-improved perturbation theories, we consider the perturbative behavior of these moments in the framework of a QCD nonpower perturbation theory, defined by the technique of series acceleration by conformal mappings, which simultaneously implements renormalization-group summation and has a tame large-order behavior. Two recently proposed models of the Adler function are employed to generate the higher-order coefficients of the perturbation series and to predict the exact values of the moments, required for testing the properties of the perturbative expansions. We show that the contour-improved nonpower perturbation theories and the renormalization-group-summed nonpower perturbation theories have very good convergence properties for a large class of moments of the so-called “reference model,” including moments that are poorly described by the standard expansions. The results provide additional support for the plausibility of the description of the Adler function in terms of a small number of dominant renormalons.
Zhou, Yun Pollak, Eli; Miret-Artés, Salvador
2014-01-14
A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to “soft” corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.
NASA Technical Reports Server (NTRS)
Melott, A. L.; Buchert, T.; Weib, A. G.
1995-01-01
We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of scales. The Lagrangian theory of gravitational instability of Friedmann-Lemaitre cosmogonies is compared with numerical simulations. We study the dynamics of hierarchical models as a second step. In the first step we analyzed the performance of the Lagrangian schemes for pancake models, the difference being that in the latter models the initial power spectrum is truncated. This work probed the quasi-linear and weakly non-linear regimes. We here explore whether the results found for pancake models carry over to hierarchical models which are evolved deeply into the non-linear regime. We smooth the initial data by using a variety of filter types and filter scales in order to determine the optimal performance of the analytical models, as has been done for the 'Zel'dovich-approximation' - hereafter TZA - in previous work. We find that for spectra with negative power-index the second-order scheme performs considerably better than TZA in terms of statistics which probe the dynamics, and slightly better in terms of low-order statistics like the power-spectrum. However, in contrast to the results found for pancake models, where the higher-order schemes get worse than TZA at late non-linear stages and on small scales, we here find that the second-order model is as robust as TZA, retaining the improvement at later stages and on smaller scales. In view of these results we expect that the second-order truncated Lagrangian model is especially useful for the modelling of standard dark matter models such as Hot-, Cold-, and Mixed-Dark-Matter.
Tomita, Kenji
2008-05-15
Second-order power spectra of cosmic microwave background (CMB) anisotropies due to random primordial perturbations at the matter-dominant stage are studied, based on the relativistic second-order theory of perturbations in flat cosmological models and on the second-order formula of CMB anisotropies derived by Mollerach and Matarrese. So far the second-order integrated Sachs-Wolfe effect has been analyzed using the three-point correlation or bispectrum. In this paper we derive the second-order term of power spectra given using the two-point correlation of temperature fluctuations. The second-order density perturbations are small, compared with the first-order ones. The second-order power spectra of CMB anisotropies, however, are not small at all, compared with the first-order power spectra, because at the early stage the first-order integrated Sachs-Wolfe effect is very small and the second-order integrated Sachs-Wolfe effect may be dominant over the first-order ones. So their characteristic behaviors may be measured through future precise observation and bring useful information on the structure and evolution of our universe in the future.
Second-order many-body perturbation study on thermal expansion of solid carbon dioxide.
Li, Jinjin; Sode, Olaseni; Hirata, So
2015-01-13
An embedded-fragment ab initio second-order many-body perturbation (MP2) method is applied to an infinite three-dimensional crystal of carbon dioxide phase I (CO2-I), using the aug-cc-pVDZ and aug-cc-pVTZ basis sets, the latter in conjunction with a counterpoise correction for the basis-set superposition error. The equation of state, phonon frequencies, bulk modulus, heat capacity, Grüneisen parameter (including mode Grüneisen parameters for acoustic modes), thermal expansion coefficient (α), and thermal pressure coefficient (β) are computed. Of the factors that enter the expression of α, MP2 reproduces the experimental values of the heat capacity, Grüneisen parameter, and molar volume accurately. However, it proves to be exceedingly difficult to determine the remaining factor, the bulk modulus (B0), the computed value of which deviates from the observed value by 50-100%. As a result, α calculated by MP2 is systematically too low, while having the correct temperature dependence. The thermal pressure coefficient, β = αB0, which is independent of B0, is more accurately reproduced by theory up to 100 K. PMID:26574220
NASA Astrophysics Data System (ADS)
Guardia, M.; Kaloshin, V.; Zhang, J.
2016-07-01
In this paper we study a so-called separatrix map introduced by Zaslavskii-Filonenko (Sov Phys JETP 27:851-857, 1968) and studied by Treschev (Physica D 116(1-2):21-43, 1998; J Nonlinear Sci 12(1):27-58, 2002), Piftankin (Nonlinearity (19):2617-2644, 2006) Piftankin and Treshchëv (Uspekhi Mat Nauk 62(2(374)):3-108, 2007). We derive a second order expansion of this map for trigonometric perturbations. In Castejon et al. (Random iteration of maps of a cylinder and diffusive behavior. Preprint available at arXiv:1501.03319, 2015), Guardia and Kaloshin (Stochastic diffusive behavior through big gaps in a priori unstable systems (in preparation), 2015), and Kaloshin et al. (Normally Hyperbolic Invariant Laminations and diffusive behavior for the generalized Arnold example away from resonances. Preprint available at http://www.terpconnect.umd.edu/vkaloshi/, 2015), applying the results of the present paper, we describe a class of nearly integrable deterministic systems with stochastic diffusive behavior.
Second order Møller-Plesset perturbation theory based upon the fragment molecular orbital method
NASA Astrophysics Data System (ADS)
Fedorov, Dmitri G.; Kitaura, Kazuo
2004-08-01
The fragment molecular orbital (FMO) method was combined with the second order Møller-Plesset (MP2) perturbation theory. The accuracy of the method using the 6-31G* basis set was tested on (H2O)n, n=16,32,64; α-helices and β-strands of alanine n-mers, n=10,20,40; as well as on (H2O)n, n=16,32,64 using the 6-31++G** basis set. Relative to the regular MP2 results that could be afforded, the FMO2-MP2 error in the correlation energy did not exceed 0.003 a.u., the error in the correlation energy gradient did not exceed 0.000 05 a.u./bohr and the error in the correlation contribution to dipole moment did not exceed 0.03 debye. An approximation reducing computational load based on fragment separation was introduced and tested. The FMO2-MP2 method demonstrated nearly linear scaling and drastically reduced the memory requirements of the regular MP2, making possible calculations with several thousands basis functions using small Pentium clusters. As an example, (H2O)64 with the 6-31++G** basis set (1920 basis functions) can be run in 1 Gbyte RAM and it took 136 s on a 40-node Pentium4 cluster.
Second-order many-body perturbation study of ice Ih.
He, Xiao; Sode, Olaseni; Xantheas, Sotiris S; Hirata, So
2012-11-28
Ice Ih is arguably the most important molecular crystal in nature, yet our understanding of its structural and dynamical properties is still far from complete. We present embedded-fragment calculations of the structures and vibrational spectra of the three-dimensional, proton-disordered phase of ice Ih performed at the level of second-order many-body perturbation theory with a basis-set superposition error correction. Our calculations address previous controversies such as the one related to the O-H bond length as well as the existence of two types of hydrogen bonds with strengths differing by a factor of two. For the latter, our calculations suggest that the observed spectral features arise from the directionality or the anisotropy of collective hydrogen-bond stretching vibrations rather than the previously suggested vastly different force constants. We also report a capability to efficiently compute infrared and Raman intensities of a periodic solid. Our approach reproduces the infrared and Raman spectra, the variation of inelastic neutron scattering spectra with deuterium concentration, and the anomaly of heat capacities at low temperatures for ice Ih. PMID:23206017
2nd Generation Reusable Launch Vehicle NASA Led Propulsion Tasks
NASA Technical Reports Server (NTRS)
Richards, Steve
2000-01-01
Design, development and test of a 2nd generation Reusable Launch Vehicle (RLV) is presented. This current paper discusses the following: 2nd Generation RLV Propulsion Project, Overview of NASA Led Tasks in Propulsion, Gen2 Turbo Machinery Technology Demonstrator, and Combustion Devices Test Bed, GRCop-84 Sheet For Combustion Chambers, Nozzles and Large Actively Cooled Structures
Rhee, Young Min; Head-Gordon, Martin
2007-02-01
Two modifications of the perturbative doubles correction to configuration interaction with single substitutions (CIS(D)) are suggested, which are excited state analogs of ground state scaled second order Moeller-Plesset (MP2) methods. The first approach employs two parameters to scale the two spin components of the direct term of CIS(D), starting from the two-parameter spin-component scaled (SCS) MP2 ground state, and is termed SCS-CIS(D). An efficient resolution-of-the-identity (RI) implementation of this approach is described. The second approach employs a single parameter to scale only the opposite-spin direct term of CIS(D), starting from the one-parameter scaled opposite spin (SOS) MP2 ground state, and is called SOS-CIS(D). By utilizing auxiliary basis expansions and a Laplace transform, a fourth order algorithm for SOS-CIS(D) is described and implemented. The parameters describing SCS-CIS(D) and SOS-CIS(D) are optimized based on a training set including valence excitations of various organic molecules and Rydberg transitions of water and ammonia, and they significantly improve upon CIS(D) itself. The accuracy of the two methods is found to be comparable. This arises from a strong correlation between the same-spin and opposite-spin portions of the excitation energy terms. The methods are successfully applied to the zincbacteriochlorin-bacteriochlorin charge transfer transition, for which time-dependent density functional theory, with presently available exchange-correlation functionals, is known to fail. The methods are also successfully applied to describe various electronic transitions outside of the training set. The efficiency of SOS-CIS(D) and the auxiliary basis implementation of CIS(D) and SCS-CIS(D) are confirmed with a series of timing tests.
NASA Astrophysics Data System (ADS)
Hannon, Kevin P.; Li, Chenyang; Evangelista, Francesco A.
2016-05-01
We report an efficient implementation of a second-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT2) [C. Li and F. A. Evangelista, J. Chem. Theory Comput. 11, 2097 (2015)]. Our implementation employs factorized two-electron integrals to avoid storage of large four-index intermediates. It also exploits the block structure of the reference density matrices to reduce the computational cost to that of second-order Møller-Plesset perturbation theory. Our new DSRG-MRPT2 implementation is benchmarked on ten naphthyne isomers using basis sets up to quintuple-ζ quality. We find that the singlet-triplet splittings (ΔST) of the naphthyne isomers strongly depend on the equilibrium structures. For a consistent set of geometries, the ΔST values predicted by the DSRG-MRPT2 are in good agreements with those computed by the reduced multireference coupled cluster theory with singles, doubles, and perturbative triples.
Wong, Justin K; Romanyk, Dan L; Toogood, Roger W; Heo, Giseon; Carey, Jason P; Major, Paul W
2014-01-01
Orthodontic literature has shown all ligation methods to behave similarly in the clinical situation; however, the reasoning behind this still requires further investigation. A novel frictional device able to measure forces at the level of the bracket along with a custom perturbation device was used to investigate the effect of perturbations on resistance to sliding (RS) using conventional and passive ligated brackets. 150 3M Victory Series twins (0.022 slot) and 150 Damon Q brackets (0.022 slot) were tested using an 0.018 x 0.025 stainless steel wire for RS. There were 5 test groups consisting of equal numbers (n=30) representing combinations of high and low amplitude and frequency of perturbations along with a control. Second order angulation tested ranged from 0 to 6 degrees. Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls. At 6 degrees, this difference (P<0.001) was seen in both high perturbation groups and one of the low perturbation groups. For passive ligated brackets, no statistically significant difference between groups was seen at 0 degrees. However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls. From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations. Also, amplitude of perturbations has a larger role than frequency in reduction of RS values. PMID:25395993
Wong, Justin K; Romanyk, Dan L; Toogood, Roger W; Heo, Giseon; Carey, Jason P
2014-01-01
Orthodontic literature has shown all ligation methods to behave similarly in the clinical situation; however, the reasoning behind this still requires further investigation. A novel frictional device able to measure forces at the level of the bracket along with a custom perturbation device was used to investigate the effect of perturbations on resistance to sliding (RS) using conventional and passive ligated brackets. 150 3M Victory Series twins (0.022 slot) and 150 Damon Q brackets (0.022 slot) were tested using an 0.018 x 0.025 stainless steel wire for RS. There were 5 test groups consisting of equal numbers (n=30) representing combinations of high and low amplitude and frequency of perturbations along with a control. Second order angulation tested ranged from 0 to 6 degrees. Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls. At 6 degrees, this difference (P<0.001) was seen in both high perturbation groups and one of the low perturbation groups. For passive ligated brackets, no statistically significant difference between groups was seen at 0 degrees. However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls. From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations. Also, amplitude of perturbations has a larger role than frequency in reduction of RS values. PMID:25395993
Twisted mass chiral perturbation theory at next-to-leading order
NASA Astrophysics Data System (ADS)
Sharpe, Stephen R.; Wu, Jackson M.
2005-04-01
We study the properties of pions in twisted mass lattice QCD (with two degenerate flavors) using chiral perturbation theory (χPT). We work to next-to-leading order (NLO) in a power-counting scheme in which mq˜aΛ2QCD, with mq the physical quark mass and a the lattice spacing. We argue that automatic O(a) improvement of physical quantities at maximal twist, which has been demonstrated in general if mq≫aΛ2QCD, holds even if mq˜aΛ2QCD, as long as one uses an appropriate nonperturbative definition of the twist angle, with the caveat that we have shown this only through NLO in our chiral expansion. We demonstrate this with explicit calculations, for arbitrary twist angle, of all pionic quantities that involve no more than a single pion in the initial and final states: masses, decay constants, form factors, and condensates, as well as the differences between alternate definitions of twist angle. We also calculate the axial and pseudoscalar form factors of the pion, quantities which violate flavor and parity, and which vanish in the continuum limit. These are of interest because they are not automatically O(a) improved at maximal twist. They allow a determination of the unknown low-energy constants introduced by discretization errors, and provide tests of the accuracy of χPT at NLO. We extend our results into the regime where mq˜a2Λ3QCD, and argue in favor of a recent proposal that automatic O(a) improvement at maximal twist remains valid in this regime.
NASA Astrophysics Data System (ADS)
Vitev, I.
We review recent developments in the QCD description of jet production and modification in reactions with heavy nuclei at relativistic energies. Our goal is to formulate a perturbative expansion in the presence of nuclear matter that allows to systematically improve the accuracy of the theoretical predictions. As an example, we present calculations of inclusive jet cross sections at RHIC, Z(0/gamma^*) -tagged jet cross sections at the LHC, and jet shapes that include both next-to-leading order perturbative effects and the effects of the nuclear medium.
Aikens, Christine M; Fletcher, Graham D; Schmidt, Michael W; Gordon, Mark S
2006-01-01
The analytic gradient expression for second-order Z-averaged perturbation theory is revised and its parallel implementation is described in detail. The distributed data interface is used to access molecular-orbital integral arrays stored in distributed memory. The algorithm is designed to maximize the use of local data and reduce communication costs. The iterative solution and the preconditioner used to induce the convergence of the coupled-perturbed Hartree-Fock equations are presented. Several illustrative timing examples are discussed. PMID:16409024
Second-order Kohn-Sham perturbation theory: correlation potential for atoms in a cavity.
Jiang, Hong; Engel, Eberhard
2005-12-01
Second-order perturbation theory based on the Kohn-Sham Hamiltonian leads to an implicit density functional for the correlation energy E(c) (MP2), which is explicitly dependent on both occupied and unoccupied Kohn-Sham single-particle orbitals and energies. The corresponding correlation potential v(c) (MP2), which has to be evaluated by the optimized potential method, was found to be divergent in the asymptotic region of atoms, if positive-energy continuum states are included in the calculation [Facco Bonetti et al., Phys. Rev. Lett. 86, 2241 (2001)]. On the other hand, Niquet et al., [J. Chem. Phys. 118, 9504 (2003)] showed that v(c) (MP2) has the same asymptotic -alpha(2r(4)) behavior as the exact correlation potential, if the system under study has a discrete spectrum only. In this work we study v(c) (MP2) for atoms in a spherical cavity within a basis-set-free finite differences approach, ensuring a completely discrete spectrum by requiring hard-wall boundary conditions at the cavity radius. Choosing this radius sufficiently large, one can devise a numerical continuation procedure which allows to normalize v(c) (MP2) consistent with the standard choice v(c)(r-->infinity)=0 for free atoms, without modifying the potential in the chemically relevant region. An important prerequisite for the success of this scheme is the inclusion of very high-energy virtual states. Using this technique, we have calculated v(c) (MP2) for all closed-shell and spherical open-shell atoms up to argon. One finds that v(c) (MP2) reproduces the shell structure of the exact correlation potential very well but consistently overestimates the corresponding shell oscillations. In the case of spin-polarized atoms one observes a strong interrelation between the correlation potentials of the two spin channels, which is completely absent for standard density functionals. However, our results also demonstrate that E(c) (MP2) can only serve as a first step towards the construction of a suitable
Chaos in the perturbed Korteweg-de Vries equation with nonlinear terms of higher order
NASA Astrophysics Data System (ADS)
Pan, Wei-Zhen; Song, Xiang-Jiong; Yu, Jun
2010-03-01
The dynamical behaviour of the generalized Korteweg-de Vries (KdV) equation under a periodic perturbation is investigated numerically. The bifurcation and chaos in the system are observed by applying bifurcation diagrams, phase portraits and Poincaré maps. To characterise the chaotic behaviour of this system, the spectra of the Lyapunov exponent and Lyapunov dimension of the attractor are also employed.
Florida Investigates 2nd Possible Local Transmission of Zika Virus
... html Florida Investigates 2nd Possible Local Transmission of Zika Virus If confirmed, cases would be first instances ... investigating a second possible case of locally transmitted Zika infection. On Tuesday, the first possible case of ...
Stirling engine design manual, 2nd edition
NASA Technical Reports Server (NTRS)
Martini, W. R.
1983-01-01
This manual is intended to serve as an introduction to Stirling cycle heat engines, as a key to the available literature on Stirling engines and to identify nonproprietary Stirling engine design methodologies. Two different fully described Stirling engines are discussed. Engine design methods are categorized as first order, second order, and third order with increased order number indicating increased complexity. FORTRAN programs are listed for both an isothermal second order design program and an adiabatic second order design program. Third order methods are explained and enumerated. In this second edition of the manual the references are updated. A revised personal and corporate author index is given and an expanded directory lists over 80 individuals and companies active in Stirling engines.
NASA Astrophysics Data System (ADS)
Mohamed, Firdawati binti; Karim, Mohamad Faisal bin Abd
2015-10-01
Modelling physical problems in mathematical form yields the governing equations that may be linear or nonlinear for known and unknown boundaries. The exact solution for those equations may or may not be obtained easily. Hence we seek an analytical approximation solution in terms of asymptotic expansion. In this study, we focus on a singular perturbation in second order ordinary differential equations. Solutions to several perturbed ordinary differential equations are obtained in terms of asymptotic expansion. The aim of this work is to find an approximate analytical solution using the classical method of matched asymptotic expansion (MMAE). The Mathematica computer algebra system is used to perform the algebraic computations. The details procedures will be discussed and the underlying concepts and principles of the MMAE will be clarified. Perturbation problem for linear equation that occurs at one boundary and two boundary layers are discussed. Approximate analytical solution obtained for both cases are illustrated by graph using selected parameter by showing the outer, inner and composite solution separately. Then, the composite solution will be compare to the exact solution to show their accuracy by graph. By comparison, MMAE is found to be one of the best methods to solve singular perturbation problems in second order ordinary differential equation since the results obtained are very close to the exact solution.
Molecular motors and the 2nd law of thermodynamics
NASA Astrophysics Data System (ADS)
Wang, Zhisong
2014-03-01
Molecular motors from biology and nanotechnology often operate on chemical energy of fuel molecules in an isothermal environment, unlike macroscopic heat engines that draw energy from a heat flow between two temperatures. Nevertheless, isothermal molecular motors are still subject to the 2nd law of thermodynamics in a fundamental way: their directional motion must cost a finite amount of energy other than the environmental heat even though no work is done; otherwise the 2nd law would be violated. Hence the 2nd law requires a finite energy price for pure direction of molecular motors. But what is the lowest price of direction allowed by the 2nd law? And how does the 2nd law-decreed price of direction limit performance of molecular motors? In the talk, I shall present our theoretical study of the 2nd law-molecular motor link on basis of the accumulated biomotor phenomenology, and also introduce our experimental effort to develop biomimetic DNA bipedal nanomotors following the mechanistic guidelines out of the theoretical study. [Main contents of this talk are from references:] This work is partially supported by FRC grants R-144-000-259-112, R-144-000-290-112 and R-144-000-320-112.
Shiozaki, Toru; Gyorffy, Werner; Celani, Paolo; Werner, Hans-Joachim
2011-08-28
The extended multireference quasi-degenerate perturbation theory, proposed by Granovsky [J. Chem. Phys. 134, 214113 (2011)], is combined with internally contracted multi-state complete active space second-order perturbation theory (XMS-CASPT2). The first-order wavefunction is expanded in terms of the union of internally contracted basis functions generated from all the reference functions, which guarantees invariance of the theory with respect to unitary rotations of the reference functions. The method yields improved potentials in the vicinity of avoided crossings and conical intersections. The theory for computing nuclear energy gradients for MS-CASPT2 and XMS-CASPT2 is also presented and the first implementation of these gradient methods is reported. A number of illustrative applications of the new methods are presented. PMID:21895152
Nayak, Malaya K.; Chaudhuri, Rajat K.
2011-02-15
The spin-rotational Hamiltonian parameters A{sub ||} and A{sub perpendicular} for the BaF molecule are calculated using four-component relativistic spinors at the second-order many-body perturbation theory (MBPT) level via the Z-vector technique. The second-order MBPT is applied to assess the accuracy of the computed hyperfine-structure constants before studying the problem with the state-of-the-artcoupled cluster with single and double excitations (CCSD) method which is highly accurate but computationally more expensive than MBPT. The hyperfine-structure constants A and A{sub d} resulted from these calculations agree favorably well with experimental findings and with other correlated calculations. The convergence behavior of A and A{sub d} with respect to the number of active orbitals used in the perturbative calculations suggests that our estimated A and A{sub d} values should be accurate.
NASA Astrophysics Data System (ADS)
Matthews, Devin A.; Gong, Justin Z.; Stanton, John F.
2014-06-01
The derivation of analytic expressions for vibrational and rovibrational constants, for example the anharmonicity constants χij and the vibration-rotation interaction constants α^B_r, from second-order vibrational perturbation theory (VPT2) can be accomplished with pen and paper and some practice. However, the corresponding quantities from fourth-order perturbation theory (VPT4) are considerably more complex, with the only known derivations by hand extensively using many layers of complicated intermediates and for rotational quantities requiring specialization to orthorhombic cases or the form of Watson's reduced Hamiltonian. We present an automatic computer program for generating these expressions with full generality based on the adaptation of an existing numerical program based on the sum-over-states representation of the energy to a computer algebra context. The measures taken to produce well-simplified and factored expressions in an efficient manner are discussed, as well as the framework for automatically checking the correctness of the generated equations.
Next-to-leading-order perturbative-QCD predictions for gammagamma-->M+M- (M=pi,K).
Duplancić, Goran; Nizić, Bene
2006-10-01
We report the first complete leading-twist next-to-leading-order perturbative-QCD predictions for the two-photon exclusive channels gammagamma-->M(+)M(-) (M=pi,K) at large momentum transfer. The asymptotic distribution amplitude is utilized as a candidate form for the nonperturbative dynamical input. Comparison of the obtained results with the existing experimental data does not provide sufficiently clear evidence to support the applicability of the hard-scattering approach at currently accessible energies. PMID:17155242
2010-01-01
Background For large-scale biological networks represented as signed graphs, the index of frustration measures how far a network is from a monotone system, i.e., how incoherently the system responds to perturbations. Results In this paper we find that the frustration is systematically lower in transcriptional networks (modeled at functional level) than in signaling and metabolic networks (modeled at stoichiometric level). A possible interpretation of this result is in terms of energetic cost of an interaction: an erroneous or contradictory transcriptional action costs much more than a signaling/metabolic error, and therefore must be avoided as much as possible. Averaging over all possible perturbations, however, we also find that unlike for transcriptional networks, in the signaling/metabolic networks the probability of finding the system in its least frustrated configuration tends to be high also in correspondence of a moderate energetic regime, meaning that, in spite of the higher frustration, these networks can achieve a globally ordered response to perturbations even for moderate values of the strength of the interactions. Furthermore, an analysis of the energy landscape shows that signaling and metabolic networks lack energetic barriers around their global optima, a property also favouring global order. Conclusion In conclusion, transcriptional and signaling/metabolic networks appear to have systematic differences in both the index of frustration and the transition to global order. These differences are interpretable in terms of the different functions of the various classes of networks. PMID:20537143
Jet algorithms in electron-positron annihilation: perturbative higher order predictions
NASA Astrophysics Data System (ADS)
Weinzierl, Stefan
2011-02-01
This article gives results on several jet algorithms in electron-positron annihilation: Considered are the exclusive sequential recombination algorithms Durham, Geneva, Jade-E0 and Cambridge, which are typically used in electron-positron annihilation. In addition also inclusive jet algorithms are studied. Results are provided for the inclusive sequential recombination algorithms Durham, Aachen and anti- k t , as well as the infrared-safe cone algorithm SISCone. The results are obtained in perturbative QCD and are N3LO for the two-jet rates, NNLO for the three-jet rates, NLO for the four-jet rates and LO for the five-jet rates.
Ladybugs of South Dakota, 2nd edition
Technology Transfer Automated Retrieval System (TEKTRAN)
Images of the 80 species of Coccinellidae, commonly known as lady beetles, that occur in South Dakota are presented in taxonomic order. The second edition updates information, including the addition of a species new to South Dakota. Information on each species includes genus-species name, sub-fami...
Hoehener, Daniel
2013-10-15
We propose second-order necessary optimality conditions for optimal control problems with very general state and control constraints which hold true under weak regularity assumptions on the data. In particular the pure state constraints are general closed sets, the optimal control is supposed to be merely measurable and the dynamics may be discontinuous in the time variable as well. These results are obtained by an approach based on local perturbations of the reference process by second-order tangent directions. This method allows direct and quite simple proofs.
Hannon, Kevin P; Li, Chenyang; Evangelista, Francesco A
2016-05-28
We report an efficient implementation of a second-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT2) [C. Li and F. A. Evangelista, J. Chem. Theory Comput. 11, 2097 (2015)]. Our implementation employs factorized two-electron integrals to avoid storage of large four-index intermediates. It also exploits the block structure of the reference density matrices to reduce the computational cost to that of second-order Møller-Plesset perturbation theory. Our new DSRG-MRPT2 implementation is benchmarked on ten naphthyne isomers using basis sets up to quintuple-ζ quality. We find that the singlet-triplet splittings (ΔST) of the naphthyne isomers strongly depend on the equilibrium structures. For a consistent set of geometries, the ΔST values predicted by the DSRG-MRPT2 are in good agreements with those computed by the reduced multireference coupled cluster theory with singles, doubles, and perturbative triples. PMID:27250283
BOOK REVIEW: Quantum Gravity (2nd edn)
NASA Astrophysics Data System (ADS)
Husain, Viqar
2008-06-01
There has been a flurry of books on quantum gravity in the past few years. The first edition of Kiefer's book appeared in 2004, about the same time as Carlo Rovelli's book with the same title. This was soon followed by Thomas Thiemann's 'Modern Canonical Quantum General Relativity'. Although the main focus of each of these books is non-perturbative and non-string approaches to the quantization of general relativity, they are quite orthogonal in temperament, style, subject matter and mathematical detail. Rovelli and Thiemann focus primarily on loop quantum gravity (LQG), whereas Kiefer attempts a broader introduction and review of the subject that includes chapters on string theory and decoherence. Kiefer's second edition attempts an even wider and somewhat ambitious sweep with 'new sections on asymptotic safety, dynamical triangulation, primordial black holes, the information-loss problem, loop quantum cosmology, and other topics'. The presentation of these current topics is necessarily brief given the size of the book, but effective in encapsulating the main ideas in some cases. For instance the few pages devoted to loop quantum cosmology describe how the mini-superspace reduction of the quantum Hamiltonian constraint of LQG becomes a difference equation, whereas the discussion of 'dynamical triangulations', an approach to defining a discretized Lorentzian path integral for quantum gravity, is less detailed. The first few chapters of the book provide, in a roughly historical sequence, the covariant and canonical metric variable approach to the subject developed in the 1960s and 70s. The problem(s) of time in quantum gravity are nicely summarized in the chapter on quantum geometrodynamics, followed by a detailed and effective introduction of the WKB approach and the semi-classical approximation. These topics form the traditional core of the subject. The next three chapters cover LQG, quantization of black holes, and quantum cosmology. Of these the chapter on LQG is
Gastrointestinal imaging in pediatrics, 2nd ed
Franken, E.A. Jr.; Smith, W.L.
1982-01-01
Gastrointestinal imaging in pediatrics is very different from its predecessor, gastrointestinal radiology in pediatrics, which was written eight years ago. The second edition is organized by anatomic area with supplemental chapters on special procedures (i.e., angiography, nuclear medicine, computerized axial tomography and ultrasonography). This volume contains 635 pages in contrast to the first edition which consisted of 323 pages. The arrangement of this volume is by anatomic area and not be clinical problem, therefore, the reader should have some background in pediatric radiology in order to find answers to specific questions.
Xiong, Hao; Si, Liu-Gang; Lü, Xin-You; Yang, Xiaoxue; Wu, Ying
2014-10-15
We propose an interesting scheme for tunable high-order sideband comb generation by utilizing ultrastrong optomechanical interaction in a GaAs optomechanical disk resonator beyond the perturbative approximation. We analyze the nonlinear nature of the optomechanical interaction, and give a full description of the non-perturbative effects. It is shown, within the non-perturbative regime, that high-order sideband comb with large intensities can be realized and controlled in a GaAs optomechanical disk resonator with experimentally achievable system parameters, and the non-perturbative regime leads to rich and nontrivial behavior.
Second-order many-body perturbation study of ice Ih
He, Xiao; Sode, Olaseni; Xantheas, Sotiris S.; Hirata, So
2012-11-28
Ice Ih is arguably the most important molecular crystal in nature, yet our understanding of its structural and dynamical properties is still incomplete. To explain the origin of two peaks in the hydrogen-bond-stretching region of the inelastic neutron scattering (INS) spectra, the existence of two types of hydrogen bonds with strengths differing by a factor of two was previously hypothesized. We present first-principles calculations based on diagrammatic many-body perturbation theory of the structures and vibrational spectra of ice Ih, which suggest that the observed spectral features arise from the directionality or anisotropy of the hydrogen-bond stretching vibrations rather than their vastly different force constants, disproving the previous hypothesis. Our calculations also reproduce the infrared and Raman spectra, the variation of INS spectra with deuterium concentration, and the anomaly of heat capacities at low temperatures, together rendering our calculations a paradigm for "crystals from first principles" as envisioned by Maddox.
Higher order statistics of curvature perturbations in IFF model and its Planck constraints
Fujita, Tomohiro; Yokoyama, Shuichiro E-mail: shu@icrr.u-tokyo.ac.jp
2013-09-01
We compute the power spectrum P{sub ζ} and non-linear parameters f{sub NL} and τ{sub NL} of the curvature perturbation induced during inflation by the electromagnetic fields in the kinetic coupling model (IFF model). By using the observational result of P{sub ζ},f{sub NL} and τ{sub NL} reported by the Planck collaboration, we study the constraint on the model comprehensively. Interestingly, if the single slow-rolling inflaton is responsible for the observed P{sub ζ}, the constraint from τ{sub NL} is most stringent. We also find a general relationship between f{sub NL} and τ{sub NL} generated in this model. Even if f{sub NL} ∼ O(1), a detectable τ{sub NL} can be produced.
Idaho National Laboratory Quarterly Performance Analysis for the 2nd Quarter FY 2015
Mitchell, Lisbeth A.
2015-04-01
This report is published quarterly by the Idaho National Laboratory (INL) Quality and Performance Management Organization. The Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS), as prescribed in DOE Order 232.2, “Occurrence Reporting and Processing of Operations Information,” requires a quarterly analysis of events, both reportable and not reportable, for the previous 12 months. This report is the analysis of events for the 2nd Qtr FY-15.
Covariant second-order perturbations in generalized two-field inflation
Tzavara, Eleftheria; Tent, Bartjan van; Mizuno, Shuntaro E-mail: Shuntaro.Mizuno@apc.univ-paris7.fr
2014-07-01
We examine the covariant properties of generalized models of two-field inflation, with non-canonical kinetic terms and a possibly non-trivial field metric. We demonstrate that kinetic-term derivatives and covariant field derivatives do commute in a proper covariant framework, which was not realized before in the literature. We also define a set of generalized slow-roll parameters, using a unified notation. Within this framework, we study the most general class of models that allows for well-defined adiabatic and entropic sound speeds, which we identify as the models with parallel momentum and field velocity vectors. For these models we write the exact cubic action in terms of the adiabatic and isocurvature perturbations. We thus provide the tool to calculate the exact non-Gaussianity beyond slow-roll and at any scale for these generalized models. We illustrate our general results by considering their long-wavelength limit, as well as with the example of two-field DBI inflation.
Vlaisavljevich, Bess; Shiozaki, Toru
2016-08-01
We report the development of the theory and computer program for analytical nuclear energy gradients for (extended) multistate complete active space perturbation theory (CASPT2) with full internal contraction. The vertical shifts are also considered in this work. This is an extension of the fully internally contracted CASPT2 nuclear gradient program recently developed for a state-specific variant by us [MacLeod and Shiozaki, J. Chem. Phys. 2015, 142, 051103]; in this extension, the so-called λ equation is solved to account for the variation of the multistate CASPT2 energies with respect to the change in the amplitudes obtained in the preceding state-specific CASPT2 calculations, and the Z vector equations are modified accordingly. The program is parallelized using the MPI3 remote memory access protocol that allows us to perform efficient one-sided communication. The optimized geometries of the ground and excited states of a copper corrole and benzophenone are presented as numerical examples. The code is publicly available under the GNU General Public License. PMID:27388038
The 2nd Generation Real Time Mission Monitor (RTMM) Development
NASA Technical Reports Server (NTRS)
Blakeslee, Richard; Goodman, Michael; Meyer, Paul; Hardin, Danny; Hall, John; He, Yubin; Regner, Kathryn; Conover, Helen; Smith, Tammy; Lu, Jessica; Garrett, Michelle
2009-01-01
The NASA Real Time Mission Monitor (RTMM) is a visualization and information system that fuses multiple Earth science data sources, to enable real time decisionmaking for airborne and ground validation experiments. Developed at the National Aeronautics and Space Administration (NASA) Marshall Space Flight Center, RTMM is a situational awareness, decision-support system that integrates satellite imagery and orbit data, radar and other surface observations (e.g., lightning location network data), airborne navigation and instrument data sets, model output parameters, and other applicable Earth science data sets. The integration and delivery of this information is made possible using data acquisition systems, network communication links, network server resources, and visualizations through the Google Earth virtual globe application. In order to improve the usefulness and efficiency of the RTMM system, capabilities are being developed to allow the end-user to easily configure RTMM applications based on their mission-specific requirements and objectives. This second generation RTMM is being redesigned to take advantage of the Google plug-in capabilities to run multiple applications in a web browser rather than the original single application Google Earth approach. Currently RTMM employs a limited Service Oriented Architecture approach to enable discovery of mission specific resources. We are expanding the RTMM architecture such that it will more effectively utilize the Open Geospatial Consortium Sensor Web Enablement services and other new technology software tools and components. These modifications and extensions will result in a robust, versatile RTMM system that will greatly increase flexibility of the user to choose which science data sets and support applications to view and/or use. The improvements brought about by RTMM 2nd generation system will provide mission planners and airborne scientists with enhanced decision-making tools and capabilities to more
Z-boson production in association with a jet at next-to-next-to-leading order in perturbative QCD
Boughezal, Radja; Campbell, John M.; Ellis, R. Keith; Focke, Christfried; Giele, Walter T.; Liu, Xiaohui; Petriello, Frank
2016-04-14
Here, we present the first complete calculation of Z-boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. Our computation uses the recently proposed N-jettiness subtraction scheme to regulate the infrared divergences that appear in the real-emission contributions. We present phenomenological results for 13 TeV proton-proton collisions with fully realistic fiducial cuts on the final-state particles. The remaining theoretical uncertainties after the inclusion of our calculations are at the percent level, making the Z+jet channel ready for precision studies at the LHC run II.
Properties of the one-dimensional Bose-Hubbard model from a high-order perturbative expansion
NASA Astrophysics Data System (ADS)
Damski, Bogdan; Zakrzewski, Jakub
2015-12-01
We employ a high-order perturbative expansion to characterize the ground state of the Mott phase of the one-dimensional Bose-Hubbard model. We compute for different integer filling factors the energy per lattice site, the two-point and density-density correlations, and expectation values of powers of the on-site number operator determining the local atom number fluctuations (variance, skewness, kurtosis). We compare these expansions to numerical simulations of the infinite-size system to determine their range of applicability. We also discuss a new sum rule for the density-density correlations that can be used in both equilibrium and non-equilibrium systems.
Z-Boson Production in Association with a Jet at Next-To-Next-To-Leading Order in Perturbative QCD.
Boughezal, Radja; Campbell, John; Ellis, R Keith; Focke, Christfried; Giele, Walter; Liu, Xiaohui; Petriello, Frank
2016-04-15
We present the first complete calculation of Z-boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. Our computation uses the recently proposed N-jettiness subtraction scheme to regulate the infrared divergences that appear in the real-emission contributions. We present phenomenological results for 13 TeV proton-proton collisions with fully realistic fiducial cuts on the final-state particles. The remaining theoretical uncertainties after the inclusion of our calculations are at the percent level, making the Z+jet channel ready for precision studies at the LHC run II. PMID:27127962
Z -Boson Production in Association with a Jet at Next-To-Next-To-Leading Order in Perturbative QCD
NASA Astrophysics Data System (ADS)
Boughezal, Radja; Campbell, John; Ellis, R. Keith; Focke, Christfried; Giele, Walter; Liu, Xiaohui; Petriello, Frank
2016-04-01
We present the first complete calculation of Z -boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. Our computation uses the recently proposed N -jettiness subtraction scheme to regulate the infrared divergences that appear in the real-emission contributions. We present phenomenological results for 13 TeV proton-proton collisions with fully realistic fiducial cuts on the final-state particles. The remaining theoretical uncertainties after the inclusion of our calculations are at the percent level, making the Z +jet channel ready for precision studies at the LHC run II.
Liu, Gang; Jayathilake, Pahala Gedara; Khoo, Boo Cheong
2014-02-01
Two nonlinear models are proposed to investigate the focused acoustic waves that the nonlinear effects will be important inside the liquid around the scatterer. Firstly, the one dimensional solutions for the widely used Westervelt equation with different coordinates are obtained based on the perturbation method with the second order nonlinear terms. Then, by introducing the small parameter (Mach number), a dimensionless formulation and asymptotic perturbation expansion via the compressible potential flow theory is applied. This model permits the decoupling between the velocity potential and enthalpy to second order, with the first potential solutions satisfying the linear wave equation (Helmholtz equation), whereas the second order solutions are associated with the linear non-homogeneous equation. Based on the model, the local nonlinear effects of focused acoustic waves on certain volume are studied in which the findings may have important implications for bubble cavitation/initiation via focused ultrasound called HIFU (High Intensity Focused Ultrasound). The calculated results show that for the domain encompassing less than ten times the radius away from the center of the scatterer, the non-linear effect exerts a significant influence on the focused high intensity acoustic wave. Moreover, at the comparatively higher frequencies, for the model of spherical wave, a lower Mach number may result in stronger nonlinear effects. PMID:24070825
NASA Astrophysics Data System (ADS)
Araújo, José M.; Dórea, Carlos E. T.; Gonçalves, Luiz M. G.; Datta, Biswa N.
2016-08-01
This paper presents a comparative study of sensitivity to parameter variation in two feedback techniques applied in second-order linear systems: state feedback technique and the less conventional state derivative feedback technique. The former uses information on displacements and velocities whereas the latter uses velocities and accelerations. Several contributions on the problem of partial or full eigenvalue/eigenstructure assignment using the state feedback technique are presented in the literature. Recently, some interesting possibilities, such as solving the regularization problem in singular mass second-order systems, are approached using state derivative feedback. In this work, a general equivalence between state feedback and state derivative feedback is first established. Then, figures of merit on the resulting perturbed spectrum are proposed in order to assess the sensitivity of the closed-loop system to variations on the system matrices. Numerical examples are presented to support the obtained results.
NASA Astrophysics Data System (ADS)
Pastore, Mariachiara; Helal, Wissam; Evangelisti, Stefano; Leininger, Thierry; Malrieu, Jean-Paul; Maynau, Daniel; Angeli, Celestino; Cimiraglia, Renzo
2008-05-01
In this paper, the problem of the calculation of the electronic structure of mixed-valence compounds is addressed in the frame of multireference perturbation theory (MRPT). Using a simple mixed-valence compound (the 5,5' (4H,4H')-spirobi[ciclopenta[c]pyrrole] 2,2',6,6' tetrahydro cation), and the n-electron valence state perturbation theory (NEVPT2) and CASPT2 approaches, it is shown that the ground state (GS) energy curve presents an unphysical "well" for nuclear coordinates close to the symmetric case, where a maximum is expected. For NEVPT, the correct shape of the energy curve is retrieved by applying the MPRT at the (computationally expensive) third order. This behavior is rationalized using a simple model (the ionized GS of two weakly interacting identical systems, each neutral system being described by two electrons in two orbitals), showing that the unphysical well is due to the canonical orbital energies which at the symmetric (delocalized) conformation lead to a sudden modification of the denominators in the perturbation expansion. In this model, the bias introduced in the second order correction to the energy is almost entirely removed going to the third order. With the results of the model in mind, one can predict that all MRPT methods in which the zero order Hamiltonian is based on canonical orbital energies are prone to present unreasonable energy profiles close to the symmetric situation. However, the model allows a strategy to be devised which can give a correct behavior even at the second order, by simply averaging the orbital energies of the two charge-localized electronic states. Such a strategy is adopted in a NEVPT2 scheme obtaining a good agreement with the third order results based on the canonical orbital energies. The answer to the question reported in the title (is this theoretical approach a reliable tool for a correct description of these systems?) is therefore positive, but care must be exercised, either in defining the orbital energies
15th order resonance terms using the decaying orbit of TETR-3. [perturbation due to gravitation
NASA Technical Reports Server (NTRS)
Wagner, C. A.; Klosko, S. M.
1975-01-01
Fifteenth-order commensurability of the orbit of TETR-3 (1971-83B) is studied. The study is designed to obtain good discrimination of 15th-order resonances through a better range of inclinations. The first low inclination orbit, 33 deg, is used for this purpose; it is very sensitive to the high degree terms which were rather poorly represented by previously analyzed orbits.
Analytic solution to leading order coupled DGLAP evolution equations: A new perturbative QCD tool
NASA Astrophysics Data System (ADS)
Block, Martin M.; Durand, Loyal; Ha, Phuoc; McKay, Douglas W.
2011-03-01
We have analytically solved the LO perturbative QCD singlet DGLAP equations [V. N. Gribov and L. N. Lipatov, Sov. J. Nucl. Phys. 15, 438 (1972)SJNCAS0038-5506][G. Altarelli and G. Parisi, Nucl. Phys. B126, 298 (1977)][Y. L. Dokshitzer, Sov. Phys. JETP 46, 641 (1977)SPHJAR0038-5646] using Laplace transform techniques. Newly developed, highly accurate, numerical inverse Laplace transform algorithms [M. M. Block, Eur. Phys. J. C 65, 1 (2010)EPCFFB1434-604410.1140/epjc/s10052-009-1195-8][M. M. Block, Eur. Phys. J. C 68, 683 (2010)EPCFFB1434-604410.1140/epjc/s10052-010-1374-7] allow us to write fully decoupled solutions for the singlet structure function Fs(x,Q2) and G(x,Q2) as Fs(x,Q2)=Fs(Fs0(x0),G0(x0)) and G(x,Q2)=G(Fs0(x0),G0(x0)), where the x0 are the Bjorken x values at Q02. Here Fs and G are known functions—found using LO DGLAP splitting functions—of the initial boundary conditions Fs0(x)≡Fs(x,Q02) and G0(x)≡G(x,Q02), i.e., the chosen starting functions at the virtuality Q02. For both G(x) and Fs(x), we are able to either devolve or evolve each separately and rapidly, with very high numerical accuracy—a computational fractional precision of O(10-9). Armed with this powerful new tool in the perturbative QCD arsenal, we compare our numerical results from the above equations with the published MSTW2008 and CTEQ6L LO gluon and singlet Fs distributions [A. D. Martin, W. J. Stirling, R. S. Thorne, and G. Watt, Eur. Phys. J. C 63, 189 (2009)EPCFFB1434-604410.1140/epjc/s10052-009-1072-5], starting from their initial values at Q02=1GeV2 and 1.69GeV2, respectively, using their choice of αs(Q2). This allows an important independent check on the accuracies of their evolution codes and, therefore, the computational accuracies of their published parton distributions. Our method completely decouples the two LO distributions, at the same time guaranteeing that both G and Fs satisfy the singlet coupled DGLAP equations. It also allows one to easily obtain the effects of
The chaos and order in human ECG under the influence of the external perturbations
NASA Astrophysics Data System (ADS)
Ragulskaya, Maria; Valeriy, Pipin
The results of the many-year telecommunication heliomedical monitoring "Heliomed" show, that space weather and geophysical factor variations serve as a training factor for the adaptation-resistant member of the human population. Here we discuss the specific properties of the human ECG discovered in our experiment. The program "Heliomed" is carried out simultaneously at the different geographical areas that cover the different latitudes. The daily registered param-eters include: the psycho-emotional tests and the 1-st lead ECG, the arterial pressure, the variability cardiac contraction, the electric conduction of bioactive points on skin. The results time series compared with daily values of space weather and geomagnetic parameters. The analysis of ECG signal proceeds as follows. At first step we construct the ECG embedding into 3D phase space using the first 3 Principal Components of the ECG time series. Next, we divide ECG on the separate cycles using the maxima of the ECG's QRS complex. Then, we filter out the non-typical ECG beats by means of the Housdorff distance. Finally, we average the example of the ECG time series along the reference trajectory and study of the dynamical characteristics of the averaged ECG beat. It is found, that the ECG signal embeded in 3D phase space can be considered as a mix of a few states. At the rest, the occurrence of the primary ECG state compare to additional ones is about 8:2. The occurrence of the primary state increases after the stress. The main effect of the external perturbation is observed in structural change of the cardio-cycle and not in the variability of the R-R interval. The num-ber of none-typical cycles increase during an isolated magnetic storm. At the all monitoring centers participating experiment the same type of changes in the cardiac activity parameters is detected to go nearly simultaneously during an isolated magnetic storm. To understand the origin of the standard cardio-cycle changes we use the dynamical
Test Review: The Profile of Mood States 2nd Edition
ERIC Educational Resources Information Center
Lin, Shuqiong; Hsiao, Yu-Yu; Wang, Miao
2014-01-01
The "Profile of Mood States 2nd Edition" (POMS 2) was published in 2012 by Multi-Health Systems (MHS) to assess transient feelings and mood among individuals aged 13 years and above. Evolving from the original POMS (McNair, Lorr, & Droppleman, 1971, 1992), the POMS 2 was designed for youth (13-17 years old) and adults (18 years old…
Book Review: Bioassays with Arthropods: 2nd Edition
Technology Transfer Automated Retrieval System (TEKTRAN)
The technical book "Bioassays with Arthropods: 2nd Edition" (2007. Jacqueline L. Robertson, Robert M. Russell, Haiganoush K, Preisler and N. E. Nevin, Eds. CRC Press, Boca Raton, FL, 224 pp.) was reviewed for the scientific readership of the peer-reviewed publication Journal of Economic Entomology. ...
A Handbook for Classroom Instruction That Works, 2nd Edition
ERIC Educational Resources Information Center
Association for Supervision and Curriculum Development, 2012
2012-01-01
Perfect for self-help and professional learning communities, this handbook makes it much easier to apply the teaching practices from the ASCD-McREL best-seller "Classroom Instruction That Works: Research-Based Strategies for Increasing Student Achievement, 2nd Edition." The authors take you through the refined Instructional Planning Guide, so you…
Quark mass relations to four-loop order in perturbative QCD.
Marquard, Peter; Smirnov, Alexander V; Smirnov, Vladimir A; Steinhauser, Matthias
2015-04-10
We present results for the relation between a heavy quark mass defined in the on-shell and minimal subtraction (MS[over ¯]) scheme to four-loop order. The method to compute the four-loop on-shell integral is briefly described and the new results are used to establish relations between various short-distance masses and the MS[over ¯] quark mass to next-to-next-to-next-to-leading order accuracy. These relations play an important role in the accurate determination of the MS[over ¯] heavy quark masses. PMID:25910112
Chu Yizen
2009-02-15
Motivated by experimental probes of general relativity, we adopt methods from perturbative (quantum) field theory to compute, up to certain integrals, the effective Lagrangian for its n-body problem. Perturbation theory is performed about a background Minkowski space-time to O[(v/c){sup 4}] beyond Newtonian gravity, where v is the typical speed of these n particles in their center of energy frame. For the specific case of the 2-body problem, the major efforts underway to measure gravitational waves produced by inspiraling compact astrophysical binaries require their gravitational interactions to be computed beyond the currently known O[(v/c){sup 7}]. We argue that such higher order post-Newtonian calculations must be automated for these field theoretic methods to be applied successfully to achieve this goal. In view of this, we outline an algorithm that would in principle generate the relevant Feynman diagrams to an arbitrary order in v/c and take steps to develop the necessary software. The Feynman diagrams contributing to the n-body effective action at O[(v/c){sup 6}] beyond Newton are derived.
NASA Astrophysics Data System (ADS)
Matsuyama, A.; Yagi, M.; Kagei, Y.; Nakajima, N.
2014-12-01
During major disruptions, an induced loop voltage accelerates runaway electrons (REs) towards high energy, being in the order of 1-100 MeV in present tokamaks and ITER. The stochastization mechanisms of such high-energy RE drift orbits are investigated by three-dimensional (3D) orbit following in tokamak plasmas. Drift resonance is shown to play an important role in determining the onset of stochastic drift orbits for different electron energies, particularly in cases with low-order perturbations that have radially global eigenfunctions of the scale of the plasma minor radius. The drift resonance due to the coupling between the cross-field drift motion with radially global modes yields a secondary island structure in the RE drift orbit, where the width of the secondary drift islands shows a square-root dependence on the relativistic gamma factor γ. Only for highly relativistic REs (γ ≫ 1), the widths of secondary drift islands are comparable with those of magnetic islands due to the primary resonance, thus the stochastic threshold becoming sensitive to the RE energy. Because of poloidal asymmetry due to toroidicity, the threshold becomes sensitive not only to the relative amplitude but also to the phase difference between the modes. In this paper, some examples of 3D orbit-following calculations are presented for analytic models of magnetic perturbations with multiple toroidal mode numbers, for both possibilities that the drift resonance enhances and suppresses the stochastization being illustrated.
Chingangbam, Pravabati; Park, Changbom E-mail: cbp@kias.re.kr
2009-12-01
We simulate CMB maps including non-Gaussianity arising from cubic order perturbations of the primordial gravitational potential, characterized by the non-linearity parameter g{sub NL}. The maps are used to study the characteristic nature of the resulting non-Gaussian temperature fluctuations. We measure the genus and investigate how it deviates from Gaussian shape as a function of g{sub NL} and smoothing scale. We find that the deviation of the non-Gaussian genus curve from the Gaussian one has an antisymmetric, sine function like shape, implying more hot and more cold spots for g{sub NL} > 0 and less of both for g{sub NL} < 0. The deviation increases linearly with g{sub NL} and also exhibits mild increase as the smoothing scale increases. We further study other statistics derived from the genus, namely, the number of hot spots, the number of cold spots, combined number of hot and cold spots and the slope of the genus curve at mean temperature fluctuation. We find that these observables carry signatures of g{sub NL} that are clearly distinct from the quadratic order perturbations, encoded in the parameter f{sub NL}. Hence they can be very useful tools for distinguishing not only between non-Gaussian temperature fluctuations and Gaussian ones but also between g{sub NL} and f{sub NL} type non-Gaussianities.
W-Boson Production in Association with a Jet at Next-to-Next-to-Leading Order in Perturbative QCD.
Boughezal, Radja; Focke, Christfried; Liu, Xiaohui; Petriello, Frank
2015-08-01
We present the complete calculation of W-boson production in association with a jet in hadronic collisions through next-to-next-to-leading order (NNLO) in perturbative QCD. To cancel infrared divergences, we discuss a new subtraction method that exploits the fact that the N-jettiness event-shape variable fully captures the singularity structure of QCD amplitudes with final-state partons. This method holds for processes with an arbitrary number of jets and is easily implemented into existing frameworks for higher-order calculations. We present initial phenomenological results for W+jet production at the LHC. The NNLO corrections are small and lead to a significantly reduced theoretical error, opening the door to precision measurements in the W+jet channel at the LHC. PMID:26296111
Cholesky-decomposed densities in Laplace-based second-order Møller-Plesset perturbation theory
NASA Astrophysics Data System (ADS)
Zienau, Jan; Clin, Lucien; Doser, Bernd; Ochsenfeld, Christian
2009-05-01
Based on our linear-scaling atomic orbital second-order Møller-Plesset perturbation theory (AO-MP2) method [J. Chem. Phys. 130, 064107 (2009)], we explore the use of Cholesky-decomposed pseudodensity (CDD) matrices within the Laplace formulation. Numerically significant contributions are preselected using our multipole-based integral estimates as upper bounds to two-electron integrals so that the 1/R6 decay behavior of transformed Coulomb-type products is exploited. In addition, we combine our new CDD-MP2 method with the resolution of the identity (RI) approach. Even though the use of RI results in a method that shows a quadratic scaling behavior in the dominant steps, gains of up to one or two orders of magnitude vs. our original AO-MP2 method are observed in particular for larger basis sets.
[Employment and education in the 2nd economic and social development plan of Togo].
Dovi-sodemekou, F B
1985-01-01
Togo is a developing country whose population is increasing at the rapid rate of 2.7%/year. Economic development is therefore a necessity to ensure at least an average standard of living. Plans of development include objectives of structural societal changes, including improvements in education and employment. This study analyzes the evolution of population activities. It identifies obstacles to the improvement of education and employment. The investigation examines the employment and education situation before adoption of the 2nd plan of Togo and predicts the probable evolution of the situation. Despite the priority accorded to agriculture, the 2nd plan appears to give greater importance to industry. The industrial and commercial sector has witnessed a 65.2% investment increase, whereas the rural sector had an investment increase of 11.8%. The 2nd plan, in view of its relation to the evolution of economic activities, took into account the demand for manual labor. In the private sector, industries should occupy an important position. The dualism of a modern and a traditional sector is considered a cause of underdevelopment. The modern sector should be developed in order to suppress the traditional sector and allow progress in society. As a result of this approach, agriculture is given a 2ndary role. PMID:12267415
NASA Astrophysics Data System (ADS)
Dimitropoulos, A.; Grishchuk, L. P.; Sathyaprakash, B. S.
The important studies of Peebles, and Bond and Efstathiou have led to the formula Cl=const./[l(l+1)] aimed at describing the lower order multipoles of the CMBR temperature variations caused by density perturbations with the flat spectrum. Clearly, this formula requires amendments, as it predicts an infinitely large monopole C0, and a dipole moment C1 only 6/2 times larger than the quadrupole C2, both predictions in conflict with observations. We restore the terms omitted in the course of the derivation of this formula, and arrive at a new expression. According to the corrected formula, the monopole moment is finite and small, while the dipole moment is sensitive to short-wavelength perturbations, and numerically much larger than the quadrupole, as one would expect on physical grounds. At the same time, the function l(l+1)Cl deviates from a horizontal line and grows with l, for l>=2. We show that the inclusion of the modulating (transfer) function terminates the growth and forms the first peak, recently observed. We fit the theoretical curves to the position and height of the first peak, as well as to the observed dipole, varying three parameters: red-shift at decoupling, red-shift at matter-radiation equality, and slope of the primordial spectrum. It appears that there is always a deficit, as compared with the COBE observations, at small multipoles, l~10. We demonstrate that a reasonable and theoretically expected amount of gravitational waves bridges this gap at small multipoles, leaving the other fits as good as before. We show that the observationally acceptable models permit somewhat ``blue'' primordial spectra. This allows one to avoid the infrared divergence of cosmological perturbations, which is otherwise present.
Extension of the chiral perturbation theory meson Lagrangian to order {ital p}{sup 6}
Fearing, H.W.; Scherer, S.
1996-01-01
We have constructed the most general chirally invariant Lagrangian {ital scrL}{sub 6} for the meson sector at order {ital p}{sup 6}. The result provides an extension of the standard Gasser-Leutwyler Lagrangian {ital scrL}{sub 4} to one higher order, including as well all the odd intrinsic parity terms in the Lagrangian. The most difficult part of the construction was developing a systematic strategy so as to get all of the independent terms and eliminate the redundant ones in an efficient way. The claim to have obtained the most general Lagrangian relies on this systematic construction and on the elimination of redundant quantities using relations of which we are aware, rather than on a general formal proof of either completeness or independence. The {open_quote}{open_quote}equation-of-motion{close_quote}{close_quote} terms, which are redundant in the sense that they can be transformed away via field transformations, are separated out explicitly. The resulting Lagrangian has been separated into groupings of terms contributing to increasingly more complicated processes, so that one does not have to deal with the full result when calculating {ital p}{sup 6} contributions to simple processes. {copyright} {ital 1995 The American Physical Society.}
Third-order perturbation theory for van der Waals interaction coefficients
Tang Liyan; Shi Tingyun; Yan Zongchao; Mitroy, J.
2011-11-15
The third-order expression for the dispersion interaction between two atoms is written as a sum over lists of transition matrix elements. Particular attention is given to the C{sub 9}/R{sup 9} interaction which occurs in the homonuclear case when one atom is in an S state and the other is in a P state. Numerical values of the C{sub 9} coefficient are given for the homonuclear alkali-metal dimers. The size of the C{sub 9}:C{sub 3} dispersion coefficient ratio increases for the heavier alkali-metal atoms. The C{sub 11} and C{sub 13} coefficients between two helium atoms and lithium atoms in their ground states are also given.
NASA Astrophysics Data System (ADS)
Gonthier, Jérôme F.; Corminboeuf, Clémence
2014-04-01
Non-covalent interactions occur between and within all molecules and have a profound impact on structural and electronic phenomena in chemistry, biology, and material science. Understanding the nature of inter- and intramolecular interactions is essential not only for establishing the relation between structure and properties, but also for facilitating the rational design of molecules with targeted properties. These objectives have motivated the development of theoretical schemes decomposing intermolecular interactions into physically meaningful terms. Among the various existing energy decomposition schemes, Symmetry-Adapted Perturbation Theory (SAPT) is one of the most successful as it naturally decomposes the interaction energy into physical and intuitive terms. Unfortunately, analogous approaches for intramolecular energies are theoretically highly challenging and virtually nonexistent. Here, we introduce a zeroth-order wavefunction and energy, which represent the first step toward the development of an intramolecular variant of the SAPT formalism. The proposed energy expression is based on the Chemical Hamiltonian Approach (CHA), which relies upon an asymmetric interpretation of the electronic integrals. The orbitals are optimized with a non-hermitian Fock matrix based on two variants: one using orbitals strictly localized on individual fragments and the other using canonical (delocalized) orbitals. The zeroth-order wavefunction and energy expression are validated on a series of prototypical systems. The computed intramolecular interaction energies demonstrate that our approach combining the CHA with strictly localized orbitals achieves reasonable interaction energies and basis set dependence in addition to producing intuitive energy trends. Our zeroth-order wavefunction is the primary step fundamental to the derivation of any perturbation theory correction, which has the potential to truly transform our understanding and quantification of non
Gonthier, Jérôme F.; Corminboeuf, Clémence
2014-04-21
Non-covalent interactions occur between and within all molecules and have a profound impact on structural and electronic phenomena in chemistry, biology, and material science. Understanding the nature of inter- and intramolecular interactions is essential not only for establishing the relation between structure and properties, but also for facilitating the rational design of molecules with targeted properties. These objectives have motivated the development of theoretical schemes decomposing intermolecular interactions into physically meaningful terms. Among the various existing energy decomposition schemes, Symmetry-Adapted Perturbation Theory (SAPT) is one of the most successful as it naturally decomposes the interaction energy into physical and intuitive terms. Unfortunately, analogous approaches for intramolecular energies are theoretically highly challenging and virtually nonexistent. Here, we introduce a zeroth-order wavefunction and energy, which represent the first step toward the development of an intramolecular variant of the SAPT formalism. The proposed energy expression is based on the Chemical Hamiltonian Approach (CHA), which relies upon an asymmetric interpretation of the electronic integrals. The orbitals are optimized with a non-hermitian Fock matrix based on two variants: one using orbitals strictly localized on individual fragments and the other using canonical (delocalized) orbitals. The zeroth-order wavefunction and energy expression are validated on a series of prototypical systems. The computed intramolecular interaction energies demonstrate that our approach combining the CHA with strictly localized orbitals achieves reasonable interaction energies and basis set dependence in addition to producing intuitive energy trends. Our zeroth-order wavefunction is the primary step fundamental to the derivation of any perturbation theory correction, which has the potential to truly transform our understanding and quantification of non
Manby, Frederick R; Werner, Hans-Joachim; Adler, Thomas B; May, Andrew J
2006-03-01
The recently introduced MP2-R122*A(loc) and LMP2-R122*A(loc) methods are modified to use a short-range correlation factor expanded as a fixed linear combination of Gaussian geminals. Density fitting is used to reduce the effort for integral evaluation, and local approximations are introduced to improve the scaling of the computational resources with molecular size. The MP2-F122*A(loc) correlation energies converge very rapidly with respect to the atomic orbital basis set size. Already with the aug-cc-pVTZ basis the correlation energies computed for a set of 21 small molecules are found to be within 0.5% of the MP2 basis set limit. Furthermore the short-range correlation factor leads to an improved convergence of the resolution of the identity, and eliminates problems with long-range errors in density fitting caused by the linear r12 factor. The DF-LMP2-F122*A(loc) method is applied to compute second-order correlation energies for molecules with up to 49 atoms and more than 1600 basis functions. PMID:16526841
The 2nd Generation Real Time Mission Monitor (RTMM) Development
NASA Astrophysics Data System (ADS)
Blakeslee, R. J.; Goodman, M.; Hardin, D. M.; Hall, J.; Yubin He, M.; Regner, K.; Conover, H.; Smith, T.; Meyer, P.; Lu, J.; Garrett, M.
2009-12-01
The NASA Real Time Mission Monitor (RTMM) is a visualization and information system that fuses multiple Earth science data sources, to enable real time decision-making for airborne and ground validation experiments. Developed at the National Aeronautics and Space Administration (NASA) Marshall Space Flight Center, RTMM is a situational awareness, decision-support system that integrates satellite imagery and orbit data, radar and other surface observations (e.g., lightning location network data), airborne navigation and instrument data sets, model output parameters, and other applicable Earth science data sets. The integration and delivery of this information is made possible using data acquisition systems, network communication links, network server resources, and visualizations through the Google Earth virtual globe application. In order to improve the usefulness and efficiency of the RTMM system, capabilities are being developed to allow the end-user to easily configure RTMM applications based on their mission-specific requirements and objectives. This second generation RTMM is being redesigned to take advantage of the Google plug-in capabilities to run multiple applications in a web browser rather than the original single application Google Earth approach. Currently RTMM employs a limited Service Oriented Architecture approach to enable discovery of mission specific resources. We are expanding the RTMM architecture such that it will more effectively utilize the Open Geospatial Consortium Sensor Web Enablement services and other new technology software tools and components. These modifications and extensions will result in a robust, versatile RTMM system that will greatly increase flexibility of the user to choose which science data sets and support applications to view and/or use. The improvements brought about by RTMM 2nd generation system will provide mission planners and airborne scientists with enhanced decision-making tools and capabilities to more
Thellamurege, Nandun M.; Si, Dejun; Cui, Fengchao; Li, Hui
2014-05-07
A combined quantum mechanical/molecular mechanical/continuum (QM/MM/C) style second order Møller-Plesset perturbation theory (MP2) method that incorporates induced dipole polarizable force field and induced surface charge continuum solvation model is established. The Z-vector method is modified to include induced dipoles and induced surface charges to determine the MP2 response density matrix, which can be used to evaluate MP2 properties. In particular, analytic nuclear gradient is derived and implemented for this method. Using the Assisted Model Building with Energy Refinement induced dipole polarizable protein force field, the QM/MM/C style MP2 method is used to study the hydrogen bonding distances and strengths of the photoactive yellow protein chromopore in the wild type and the Glu46Gln mutant.
NASA Astrophysics Data System (ADS)
Casanova, David
2014-04-01
Second-order corrections to the restricted active space configuration interaction (RASCI) with the hole and particle truncation of the excitation operator are developed. Theoretically, the computational cost of the implemented perturbative approach, abbreviated as RASCI(2), grows like its single reference counterpart in MP2. Two different forms of RASCI(2) have been explored, that is the generalized Davidson-Kapuy and the Epstein-Nesbet partitions of the Hamiltonian. The preliminary results indicate that the use of energy level shift of a few tenths of a Hartree might systematically improve the accuracy of the RASCI(2) energies. The method has been tested in the computation of the ground state energy profiles along the dissociation of the hydrogen fluoride and N2 molecules, the computation of correlation energy in the G2/97 molecular test set, and in the computation of excitation energies to low-lying states in small organic molecules.
Mott-insulator phase of the one-dimensional Bose-Hubbard model: A high-order perturbative study
NASA Astrophysics Data System (ADS)
Damski, Bogdan; Zakrzewski, Jakub
2006-10-01
The one-dimensional Bose-Hubbard model at a unit filling factor is studied by means of a very high-order symbolic perturbative expansion. Analytical expressions are derived for the ground-state quantities such as energy per site, variance of on-site occupation, and correlation functions: ⟨âj†âj+r⟩ and ⟨n̂jn̂j+r⟩ . These findings are compared to numerics and good agreement is found in the Mott insulator phase. Our results provide analytical approximations to important observables in the Mott phase, and are also of direct relevance to future experiments with ultracold atomic gases placed in optical lattices. We also discuss the symmetry of the Bose-Hubbard model associated with the sign change of the tunneling coupling.
Casanova, David
2014-04-14
Second-order corrections to the restricted active space configuration interaction (RASCI) with the hole and particle truncation of the excitation operator are developed. Theoretically, the computational cost of the implemented perturbative approach, abbreviated as RASCI(2), grows like its single reference counterpart in MP2. Two different forms of RASCI(2) have been explored, that is the generalized Davidson-Kapuy and the Epstein-Nesbet partitions of the Hamiltonian. The preliminary results indicate that the use of energy level shift of a few tenths of a Hartree might systematically improve the accuracy of the RASCI(2) energies. The method has been tested in the computation of the ground state energy profiles along the dissociation of the hydrogen fluoride and N{sub 2} molecules, the computation of correlation energy in the G2/97 molecular test set, and in the computation of excitation energies to low-lying states in small organic molecules.
Thirman, Jonathan Head-Gordon, Martin
2015-08-28
An energy decomposition analysis (EDA) of intermolecular interactions is proposed for second-order Møller–Plesset perturbation theory (MP2) based on absolutely localized molecular orbitals (ALMOs), as an extension to a previous ALMO-based EDA for self-consistent field methods. It decomposes the canonical MP2 binding energy by dividing the double excitations that contribute to the MP2 wave function into classes based on how the excitations involve different molecules. The MP2 contribution to the binding energy is decomposed into four components: frozen interaction, polarization, charge transfer, and dispersion. Charge transfer is defined by excitations that change the number of electrons on a molecule, dispersion by intermolecular excitations that do not transfer charge, and polarization and frozen interactions by intra-molecular excitations. The final two are separated by evaluations of the frozen, isolated wave functions in the presence of the other molecules, with adjustments for orbital response. Unlike previous EDAs for electron correlation methods, this one includes components for the electrostatics, which is vital as adjustment to the electrostatic behavior of the system is in some cases the dominant effect of the treatment of electron correlation. The proposed EDA is then applied to a variety of different systems to demonstrate that all proposed components behave correctly. This includes systems with one molecule and an external electric perturbation to test the separation between polarization and frozen interactions and various bimolecular systems in the equilibrium range and beyond to test the rest of the EDA. We find that it performs well on these tests. We then apply the EDA to a halogen bonded system to investigate the nature of the halogen bond.
Effects of Thermal Cycling on Control and Irradiated EPC 2nd Generation GaN FETs
NASA Technical Reports Server (NTRS)
Patterson, Richard L.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad
2013-01-01
The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling in order to address their reliability for use in space missions. Results of the experimental work are presented and discussed.
Wang, Yang Min; Hättig, Christof; Reine, Simen; Valeev, Edward; Kjærgaard, Thomas; Kristensen, Kasper
2016-05-28
We present the DEC-RIMP2-F12 method where we have augmented the Divide Expand-Consolidate resolution-of-the-identity second-order Møller-Plesset perturbation theory method (DEC-RIMP2) [P. Baudin et al., J. Chem. Phys. 144, 054102 (2016)] with an explicitly correlated (F12) correction. The new method is linear-scaling, massively parallel, and it corrects for the basis set incompleteness error in an efficient manner. In addition, we observe that the F12 contribution decreases the domain error of the DEC-RIMP2 correlation energy by roughly an order of magnitude. An important feature of the DEC scheme is the inherent error control defined by a single parameter, and this feature is also retained for the DEC-RIMP2-F12 method. In this paper we present the working equations for the DEC-RIMP2-F12 method and proof of concept numerical results for a set of test molecules. PMID:27250284
NASA Astrophysics Data System (ADS)
Hohenstein, Edward G.; Parrish, Robert M.; Martínez, Todd J.
2012-07-01
Many approximations have been developed to help deal with the O(N4) growth of the electron repulsion integral (ERI) tensor, where N is the number of one-electron basis functions used to represent the electronic wavefunction. Of these, the density fitting (DF) approximation is currently the most widely used despite the fact that it is often incapable of altering the underlying scaling of computational effort with respect to molecular size. We present a method for exploiting sparsity in three-center overlap integrals through tensor decomposition to obtain a low-rank approximation to density fitting (tensor hypercontraction density fitting or THC-DF). This new approximation reduces the 4th-order ERI tensor to a product of five matrices, simultaneously reducing the storage requirement as well as increasing the flexibility to regroup terms and reduce scaling behavior. As an example, we demonstrate such a scaling reduction for second- and third-order perturbation theory (MP2 and MP3), showing that both can be carried out in O(N4) operations. This should be compared to the usual scaling behavior of O(N5) and O(N6) for MP2 and MP3, respectively. The THC-DF technique can also be applied to other methods in electronic structure theory, such as coupled-cluster and configuration interaction, promising significant gains in computational efficiency and storage reduction.
Ng, Yee-Hong; Bettens, Ryan P A
2016-03-01
Using the method of modified Shepard's interpolation to construct potential energy surfaces of the H2O, O3, and HCOOH molecules, we compute vibrationally averaged isotropic nuclear shielding constants ⟨σ⟩ of the three molecules via quantum diffusion Monte Carlo (QDMC). The QDMC results are compared to that of second-order perturbation theory (PT), to see if second-order PT is adequate for obtaining accurate values of nuclear shielding constants of molecules with large amplitude motions. ⟨σ⟩ computed by the two approaches differ for the hydrogens and carbonyl oxygen of HCOOH, suggesting that for certain molecules such as HCOOH where big displacements away from equilibrium happen (internal OH rotation), ⟨σ⟩ of experimental quality may only be obtainable with the use of more sophisticated and accurate methods, such as quantum diffusion Monte Carlo. The approach of modified Shepard's interpolation is also extended to construct shielding constants σ surfaces of the three molecules. By using a σ surface with the equilibrium geometry as a single data point to compute isotropic nuclear shielding constants for each descendant in the QDMC ensemble representing the ground state wave function, we reproduce the results obtained through ab initio computed σ to within statistical noise. Development of such an approach could thereby alleviate the need for any future costly ab initio σ calculations. PMID:26835785
Two 2nd Circuit decisions represent mixed bag on insurance.
2000-01-21
The 2nd U.S. Circuit Court of Appeals in New York issued two important rulings within a week on the extent to which the Americans with Disabilities Act (ADA) regulates insurance practices. [Name removed] v. Allstate Life Insurance Co. was a plaintiff-friendly decision, finding that the insurance company illegally refused to sell life insurance to a married couple because of their mental disability, major depression. [Name removed]. v. Israel Discount Bank of New York was more defendant friendly and tackled the issue of whether the ADA permits different benefit caps for mental and physical disabilities. PMID:11367226
NASA Astrophysics Data System (ADS)
Goldey, Matthew; Head-Gordon, Martin
2015-03-01
Second order Møller-Plesset perturbation theory (MP2) in finite basis sets describes several classes of noncovalent interactions poorly due to basis set superposition error (BSSE) and underlying inaccurate physics for dispersion interactions. Attenuation of the Coulomb operator provides a direct path toward improving MP2 for noncovalent interactions. In limited basis sets, we demonstrate improvements in accuracy for intermolecular interactions with a three to five-fold reduction in RMS errors. For a range of inter- and intermolecular test cases, attenuated MP2 even outperforms complete basis set estimates of MP2. Finite basis attenuated MP2 is useful for inter- and intramolecular interactions where higher cost approaches are intractable. Extending this approach, recent research pairs attenuated MP2 with long-range correction to describe potential energy landscapes, and further results for large systems with noncovalent interactions are shown. This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. We acknowledge computational resources obtained under NSF Award CHE-1048789.
Stanton, John F
2016-07-21
Semiclassical transition-state theory based on fourth-order vibrational perturbation theory (VPT4-SCTST) is applied to compute the barrier transmission coefficient for the symmetric Eckart potential. For a barrier parametrized to mimic the H2 + H exchange reaction, the results obtained are in excellent agreement with exact quantum calculations over a range of energy that extends down to roughly 1% of the barrier height, V0, where tunneling is negligible. The VPT2-SCTST treatment, which is commonly used in chemical kinetics studies, also performs quite well but already shows an error of a few percent at ca. 0.8 V0 where tunneling is still important. This suggests that VPT4-SCTST could offer an improvement over VPT2-SCTST in applications studies. However, the computational effort for VPT4-SCTST treatments of molecules is excessive, and any improvement gained is unlikely to warrant the increased effort. Nevertheless, the treatment of the symmetric Eckart barrier problem here suggests a simple modification of the usual VPT2-SCTST protocol that warrants further investigation. PMID:27358083
NASA Astrophysics Data System (ADS)
Burkholder, Michael B.; Litster, Shawn
2015-02-01
Polymer electrolyte fuel cell (PEFC) system efficiency can be decreased by instabilities resulting from the accumulation of water in the cathode as well as by excessive air delivery parasitic loads used to prevent liquid water accumulation. In this work, we present a new instability detection diagnostic tailored for the nonlinear and chaotic dynamics of PEFC operation with multi-phase flow in the gas channels. The instability statistic, the Lyapunov exponent of the reduced-order voltage return map, λ, is a measure of the exponential rate of divergence in the dynamic voltage signal measured from the fuel cell. A key advantage of this statistic for embedded control is that it is a self-referencing measure of the system stability for feedback and is not based on an a priori performance threshold. Our experiments demonstrate that the Lyapunov exponent statistic provides a warning typically 100 s in advance of significant power loss. Using this statistic as a control diagnostic, a new control scheme that detects PEFC instability in real time and mitigates it with pressure perturbations was applied experimentally to several fuel cell systems, including one that simulates stack operation. Our control scheme resulted in increased PEFC power, decreased cathode flooding leading to a lower parasitic load for air delivery, and stable PEFC performance.
Rusakova, Irina L; Krivdin, Leonid B
2013-11-01
A double perturbation theory (DPT) at the second order level of approximation formalism has been applied to examine the dihedral angle dependence of the Fermi-contact (FC) contribution to nuclear spin-spin coupling constants. The unperturbed wave function of the ground state in DPT was approximated by the Hartree-Fock Slater determinant, while the excited states were treated as the single excited determinants. An analytical expression relating the FC term of vicinal proton-proton spin-spin coupling constants across the aliphatic single carbon-carbon bond to the dihedral angle describing inner rotation around the C-C bond in the ten-electron ten-orbital moiety H-C-C-H has been derived and analyzed. In particular, it has been shown that extrema of (3)J(H,H) are observed at φ = πn, n = 0, ±1, ±2,…, which provides a theoretical background of a well-known semiempirical Karplus equation. PMID:24071769
The crystal structure of ^7Li2ND
NASA Astrophysics Data System (ADS)
Tsubota, Masami; Sorby, Magnus H.; Hino, Satoshi; Ichikawa, Takayuki; Hauback, Bjorn C.; Kojima, Yoshitsugu
2008-03-01
Recently much attention has been given to reversible hydrogen storage materials possessing high gravimetric capacity. Lithium amide/imide systems are promising candidates. Chen et al.[1] found that a mixture of lithium amide and lithium hydride can reversibly store hydrogen up to 6.5 mass% forming lithium imide (Li2NH). Among them, the crystal structure of Li2NH is still controversial. Balogh et al.[2] have reported a cubic structure model. However, this model differs significantly from theoretical structure models. In this work, the crystal structure of the isotopically substituted ^7Li2ND has been investigated by powder neutron and synchrotron X-ray diffraction experiments. In our data some peaks, which should be a single peak for cubic symmetry, were obviously split indicating a lower symmetry than cubic for lithium imide. The structure of ^7Li2ND will be described. [1] P. Chen et al., J. Phys. Chem. B 107 (2003) 10967. [2] M.P. Balogh et al., J. Alloys Compd. 420 (2006) 326.
2nd Generation RLV: Program Goals and Acquisition Strategy
NASA Technical Reports Server (NTRS)
Graham, J. Bart; Dumbacher, D. L. (Technical Monitor)
2001-01-01
The risk to loss of life for Space Shuttle crewmembers is approximately one in 245 missions. U.S. launch service providers captured nearly 100%, of the commercial launch market revenues in the mid 1980s. Today, the U.S. captures less than 50% of that market. A launch system architecture is needed that will dramatically increase the safety of space flight while significantly reducing the cost. NASA's Space Launch Initiative, which is implemented by the 2nd Generation RLV Program Office at Marshall Space Flight Center, seeks to develop technology and reusable launch vehicle concepts which satisfy the commercial launch market needs and the unique needs of NASA. Presented in this paper are the five primary elements of NASA's Integrated Space Transportation Plan along with the highest level goals and the acquisition strategy of the 2nd Generation RLV Program. Approval of the Space Launch Initiative FY01 budget of $290M is seen as a major commitment by the Agency and the Nation to realize the commercial potential that space offers and to move forward in the exploration of space.
NASA Technical Reports Server (NTRS)
Thomas, Dale; Smith, Charles; Thomas, Leann; Kittredge, Sheryl
2002-01-01
The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and business risks associated with developing a new class of reusable launch vehicles. NASA's specific goals are to improve the safety of a 2nd generation system by 2 orders of magnitude - equivalent to a crew risk of 1-in-10,000 missions - and decrease the cost tenfold, to approximately $1,000 per pound of payload launched. Architecture definition is being conducted in parallel with the maturating of key technologies specifically identified to improve safety and reliability, while reducing operational costs. An architecture broadly includes an Earth-to-orbit reusable launch vehicle, on-orbit transfer vehicles and upper stages, mission planning, ground and flight operations, and support infrastructure, both on the ground and in orbit. The systems engineering approach ensures that the technologies developed - such as lightweight structures, long-life rocket engines, reliable crew escape, and robust thermal protection systems - will synergistically integrate into the optimum vehicle. To best direct technology development decisions, analytical models are employed to accurately predict the benefits of each technology toward potential space transportation architectures as well as the risks associated with each technology. Rigorous systems analysis provides the foundation for assessing progress toward safety and cost goals. The systems engineering review process factors in comprehensive budget estimates, detailed project schedules, and business and performance plans, against the goals of safety, reliability, and cost, in addition to overall technical feasibility. This approach forms the basis for investment decisions in the 2nd Generation RLV Program's risk-reduction activities. Through this process, NASA will continually refine its specialized needs and identify where Defense and commercial requirements overlap those of civil missions.
Life Cycle Systems Engineering Approach to NASA's 2nd Generation Reusable Launch Vehicle
NASA Technical Reports Server (NTRS)
Thomas, Dale; Smith, Charles; Safie, Fayssal; Kittredge, Sheryl
2002-01-01
The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and business risks associated with developing a new class of reusable launch vehicles. NASA's specific goals are to improve the safety of a 2nd- generation system by 2 orders of magnitude - equivalent to a crew risk of 1 -in- 10,000 missions - and decrease the cost tenfold, to approximately $1,000 per pound of payload launched. Architecture definition is being conducted in parallel with the maturating of key technologies specifically identified to improve safety and reliability, while reducing operational costs. An architecture broadly includes an Earth-to-orbit reusable launch vehicle, on-orbit transfer vehicles and upper stages, mission planning, ground and flight operations, and support infrastructure, both on the ground and in orbit. The systems engineering approach ensures that the technologies developed - such as lightweight structures, long-life rocket engines, reliable crew escape, and robust thermal protection systems - will synergistically integrate into the optimum vehicle. Given a candidate architecture that possesses credible physical processes and realistic technology assumptions, the next set of analyses address the system's functionality across the spread of operational scenarios characterized by the design reference missions. The safety/reliability and cost/economics associated with operating the system will also be modeled and analyzed to answer the questions "How safe is it?" and "How much will it cost to acquire and operate?" The systems engineering review process factors in comprehensive budget estimates, detailed project schedules, and business and performance plans, against the goals of safety, reliability, and cost, in addition to overall technical feasibility. This approach forms the basis for investment decisions in the 2nd Generation RLV Program's risk-reduction activities. Through this process, NASA will continually refine its specialized needs and
NASA Technical Reports Server (NTRS)
Thomas, Dale; Smith, Charles; Thomas, Leann; Kittredge, Sheryl
2002-01-01
The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and business risks associated with developing a new class of reusable launch vehicles. NASA's specific goals are to improve the safety of a 2nd-generation system by 2 orders of magnitude - equivalent to a crew risk of 1-in-10,000 missions - and decrease the cost tenfold, to approximately $1,000 per pound of payload launched. Architecture definition is being conducted in parallel with the maturating of key technologies specifically identified to improve safety and reliability, while reducing operational costs. An architecture broadly includes an Earth-to-orbit reusable launch vehicle, on-orbit transfer vehicles and upper stages, mission planning, ground and flight operations, and support infrastructure, both on the ground and in orbit. The systems engineering approach ensures that the technologies developed - such as lightweight structures, long-life rocket engines, reliable crew escape, and robust thermal protection systems - will synergistically integrate into the optimum vehicle. To best direct technology development decisions, analytical models are employed to accurately predict the benefits of each technology toward potential space transportation architectures as well as the risks associated with each technology. Rigorous systems analysis provides the foundation for assessing progress toward safety and cost goals. The systems engineering review process factors in comprehensive budget estimates, detailed project schedules, and business and performance plans, against the goals of safety, reliability, and cost, in addition to overall technical feasibility. This approach forms the basis for investment decisions in the 2nd Generation RLV Program's risk-reduction activities. Through this process, NASA will continually refine its specialized needs and identify where Defense and commercial requirements overlap those of civil missions.
Herbert, J.M.
1997-07-01
Rayleigh-Schroedinger perturbation theory is an effective and popular tool for describing low-lying vibrational and rotational states of molecules. This method, in conjunction with ab initio techniques for computation of electronic potential energy surfaces, can be used to calculate first-principles molecular vibrational-rotational energies to successive orders of approximation. Because of mathematical complexities, however, such perturbation calculations are rarely extended beyond the second order of approximation, although recent work by Herbert has provided a formula for the nth-order energy correction. This report extends that work and furnishes the remaining theoretical details (including a general formula for the Rayleigh-Schroedinger expansion coefficients) necessary for calculation of energy corrections to arbitrary order. The commercial computer algebra software Mathematica is employed to perform the prohibitively tedious symbolic manipulations necessary for derivation of generalized energy formulae in terms of universal constants, molecular constants, and quantum numbers. As a pedagogical example, a Hamiltonian operator tailored specifically to diatomic molecules is derived, and the perturbation formulae obtained from this Hamiltonian are evaluated for a number of such molecules. This work provides a foundation for future analyses of polyatomic molecules, since it demonstrates that arbitrary-order perturbation theory can successfully be applied with the aid of commercially available computer algebra software.
PREFACE: 2nd International Meeting for Researchers in Materials and Plasma Technology
NASA Astrophysics Data System (ADS)
Niño, Ely Dannier V.
2013-11-01
These proceedings present the written contributions of the participants of the 2nd International Meeting for Researchers in Materials and Plasma Technology, 2nd IMRMPT, which was held from February 27 to March 2, 2013 at the Pontificia Bolivariana Bucaramanga-UPB and Santander and Industrial - UIS Universities, Bucaramanga, Colombia, organized by research groups from GINTEP-UPB, FITEK-UIS. The IMRMPT, was the second version of biennial meetings that began in 2011. The three-day scientific program of the 2nd IMRMPT consisted in 14 Magisterial Conferences, 42 Oral Presentations and 48 Poster Presentations, with the participation of undergraduate and graduate students, professors, researchers and entrepreneurs from Colombia, Russia, France, Venezuela, Brazil, Uruguay, Argentina, Peru, Mexico, United States, among others. Moreover, the objective of IMRMPT was to bring together national and international researchers in order to establish scientific cooperation in the field of materials science and plasma technology; introduce new techniques of surface treatment of materials to improve properties of metals in terms of the deterioration due to corrosion, hydrogen embrittlement, abrasion, hardness, among others; and establish cooperation agreements between universities and industry. The topics covered in the 2nd IMRMPT include New Materials, Surface Physics, Laser and Hybrid Processes, Characterization of Materials, Thin Films and Nanomaterials, Surface Hardening Processes, Wear and Corrosion / Oxidation, Modeling, Simulation and Diagnostics, Plasma Applications and Technologies, Biomedical Coatings and Surface Treatments, Non Destructive Evaluation and Online Process Control, Surface Modification (Ion Implantation, Ion Nitriding, PVD, CVD). The editors hope that those interested in the are of materials science and plasma technology, enjoy the reading that reflect a wide range of topics. It is a pleasure to thank the sponsors and all the participants and contributors for
Glueck, M.; Reya, E.; Pisano, C.
2008-04-01
Recent measurements for F{sub 2}(x,Q{sup 2}) have been analyzed in terms of the 'dynamical' and 'standard' parton model approach at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) of perturbative QCD. Having fixed the relevant NLO and NNLO parton distributions, we present the implications and predictions for the longitudinal structure function F{sub L}(x,Q{sup 2}). It is shown that the previously noted extreme perturbative NNLO/NLO instability of F{sub L}(x,Q{sup 2}) is an artifact of the commonly utilized 'standard' gluon distributions. In particular it is demonstrated that using the appropriate--dynamically generated--parton distributions at NLO and NNLO, F{sub L}(x,Q{sup 2}) turns out to be perturbatively rather stable already for Q{sup 2}{>=}O(2-3 GeV{sup 2})
Philips' 2nd generation Novallure LED candle lamp
NASA Astrophysics Data System (ADS)
Li, Yun; Pei, Zhigang; Yuan, Chuan; Jiang, Tan; Lu, Zhengsong; Wang, Yuqian; Duan, Xiaoqing; Xiong, Yan; Zhong, Hong; Liu, Ye
2010-08-01
Finding an energy efficient replacement of incandescent candle lamp has been a technical challenge. Compact fluorescent lamps, for example, can be miniaturized to fit the form factor of a candle lamp but they fail to reproduce its "sparkle" effect. Empowered by solid state lighting technology along with original optical design, Philips has successfully developed LED-powered candle lamps "Novallure" with great energy savings (2W power consumption with lumen output of 55 lumen) and the "butterfly" radiation pattern that mimics the sparkle effect from an incandescent candle lamp. With new high performance LED packages, novel under-cut prismatic optics and state-of-the-art electronic driver solution and thermal solution, we have developed a 2nd generation Novallure with breakthrough performance: a dimmable 2700K 136 lumen LED candle lamp with CRI 90.
Čársky, Petr
2015-01-22
So far the second-order perturbation theory has been only applied to the hydrogen molecule. No application was attempted for another molecule, probably because of technical difficulties of such calculations. The purpose of this contribution is to show that the calculations of this type are now feasible on larger polyatomic molecules even on commonly used computers.
Super Boiler 2nd Generation Technology for Watertube Boilers
Mr. David Cygan; Dr. Joseph Rabovitser
2012-03-31
This report describes Phase I of a proposed two phase project to develop and demonstrate an advanced industrial watertube boiler system with the capability of reaching 94% (HHV) fuel-to-steam efficiency and emissions below 2 ppmv NOx, 2 ppmv CO, and 1 ppmv VOC on natural gas fuel. The boiler design would have the capability to produce >1500 F, >1500 psig superheated steam, burn multiple fuels, and will be 50% smaller/lighter than currently available watertube boilers of similar capacity. This project is built upon the successful Super Boiler project at GTI. In that project that employed a unique two-staged intercooled combustion system and an innovative heat recovery system to reduce NOx to below 5 ppmv and demonstrated fuel-to-steam efficiency of 94% (HHV). This project was carried out under the leadership of GTI with project partners Cleaver-Brooks, Inc., Nebraska Boiler, a Division of Cleaver-Brooks, and Media and Process Technology Inc., and project advisors Georgia Institute of Technology, Alstom Power Inc., Pacific Northwest National Laboratory and Oak Ridge National Laboratory. Phase I of efforts focused on developing 2nd generation boiler concepts and performance modeling; incorporating multi-fuel (natural gas and oil) capabilities; assessing heat recovery, heat transfer and steam superheating approaches; and developing the overall conceptual engineering boiler design. Based on our analysis, the 2nd generation Industrial Watertube Boiler when developed and commercialized, could potentially save 265 trillion Btu and $1.6 billion in fuel costs across U.S. industry through increased efficiency. Its ultra-clean combustion could eliminate 57,000 tons of NOx, 460,000 tons of CO, and 8.8 million tons of CO2 annually from the atmosphere. Reduction in boiler size will bring cost-effective package boilers into a size range previously dominated by more expensive field-erected boilers, benefiting manufacturers and end users through lower capital costs.
NASA Astrophysics Data System (ADS)
Gwaltney, Steven R.; Sherrill, C. David; Head-Gordon, Martin; Krylov, Anna I.
2000-09-01
We present a general perturbative method for correcting a singles and doubles coupled-cluster energy. The coupled-cluster wave function is used to define a similarity-transformed Hamiltonian, which is partitioned into a zeroth-order part that the reference problem solves exactly plus a first-order perturbation. Standard perturbation theory through second-order provides the leading correction. Applied to the valence optimized doubles (VOD) approximation to the full-valence complete active space self-consistent field method, the second-order correction, which we call (2), captures dynamical correlation effects through external single, double, and semi-internal triple and quadruple substitutions. A factorization approximation reduces the cost of the quadruple substitutions to only sixth order in the size of the molecule. A series of numerical tests are presented showing that VOD(2) is stable and well-behaved provided that the VOD reference is also stable. The second-order correction is also general to standard unwindowed coupled-cluster energies such as the coupled-cluster singles and doubles (CCSD) method itself, and the equations presented here fully define the corresponding CCSD(2) energy.
NASA Astrophysics Data System (ADS)
McGovern, Judith
2013-04-01
The recent determination of the proton charge radius from the Lamb shift in muonic hydrogen [1] gives a value that differs by many standard deviations from the CODATA value [2] and from the results of recent electron scattering experiments [3]. In the theoretical calculations [4], the least-well-determined contribution is the ``proton polarisability'' contribution. This is the part of the two-photon exchange which involves proton excitations. The dominant effect can be determined via dispersion relations from the proton structure functions, but a subtraction term remains [5,6]. This subtraction term is the amplitude T1(0,Q^2) for forward, zero-energy, doubly-virtual Compton scattering, which we calculate in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the γNδ form factor. This provides a model-independent expression for the amplitude in the low-momentum region, which is the dominant one for its contribution to the Lamb shift, and allows us to significantly reduce the theoretical uncertainty in the latter [7].[4pt] [1] R. Pohl et al., Nature 466, 213 (2010).[0pt] [2] P. J. Mohr, B. N. Taylor and D. B. Newell, Rev. Mod. Phys. 80, 633 (2008) [arXiv:0801.0028].[0pt] [3] J. C. Bernauer et al. (A1 Collaboration), Phys. Rev. Lett. 105, 242001 (2010) [arXiv:1007.5076].[0pt] [4] U. D. Jentschura, Ann. Phys. 326, 500 (2011) [arXiv:1011.5275]; E. Borie, Ann. Phys. 327, 733 (2012) [arXiv:1103.1772].[0pt] [5] K. Pachucki, Phys. Rev. A 60, 3593 (1999) [arXiv:physics/9906002].[0pt] [6] C. E. Carlson and M. Vanderhaeghen, Phys. Rev. A 84, 020102 (2011) [arXiv:1101.5965]; also [arXiv:1109.3779].[0pt] [7] M. C. Birse and J. A. McGovern, Eur. Phys. J. A48, 120 (2012) [arXiv:1206.3030].
Physical properties of double perovskite-type barium neodymium osmate Ba{sub 2}NdOsO{sub 6}
Wakeshima, Makoto; Hinatsu, Yukio; Ohoyama, Kenji
2013-01-15
The crystal, magnetic structures and physical properties of the double perovskite-type barium neodymium osmate Ba{sub 2}NdOsO{sub 6} are investigated through powder X-ray and neutron diffraction, electrical conductivity, magnetic susceptibility, and specific heat measurements. The Rietveld analysis reveals that the Nd and Os ions are arranged with regularity over the six-coordinate B sites in a distorted perovskite ABO{sub 3} framework. The monoclinic crystal structure described by space group P2{sub 1}/n (tilt system a{sup -}a{sup -}c{sup +}) becomes more distorted with decreasing temperature from 300 K down to 2.5 K. This compound shows a long-range antiferromagnetic ordering of Os{sup 5+} below 65 K. An antiferromagnetic ordering of Nd{sup 3+} also occurs at lower temperatures ({approx}20 K). The magnetic structure is of Type I and the magnetic moments of Nd{sup 3+} and Os{sup 5+} ions are in the same direction in the ab-plane. - Graphical Abstract: The Magnetic structure of Ba{sub 2}NdOsO{sub 6} is of Type I, and the magnetic moments of the Nd{sup 3+} and Os{sup 5+} ions are in the same direction in the ab-plane. Highlights: Black-Right-Pointing-Pointer Crystal structures of Ba{sub 2}NdOsO{sub 6} are determined to be monoclinic below 300 K. Black-Right-Pointing-Pointer Its electrical resistivity shows a Mott variable-range hopping behavior with localized carriers. Black-Right-Pointing-Pointer An antiferromagnetic ordering of the Os{sup 5+}moment occurs at 65 K. Black-Right-Pointing-Pointer The magnetic structure of Ba{sub 2}NdOsO{sub 6} is determined to be of Type I.
NASA Astrophysics Data System (ADS)
Chen, Zhenhua; Hoffmann, Mark R.
2012-07-01
A unitary wave operator, exp (G), G+ = -G, is considered to transform a multiconfigurational reference wave function Φ to the potentially exact, within basis set limit, wave function Ψ = exp (G)Φ. To obtain a useful approximation, the Hausdorff expansion of the similarity transformed effective Hamiltonian, exp (-G)Hexp (G), is truncated at second order and the excitation manifold is limited; an additional separate perturbation approximation can also be made. In the perturbation approximation, which we refer to as multireference unitary second-order perturbation theory (MRUPT2), the Hamiltonian operator in the highest order commutator is approximated by a Møller-Plesset-type one-body zero-order Hamiltonian. If a complete active space self-consistent field wave function is used as reference, then the energy is invariant under orbital rotations within the inactive, active, and virtual orbital subspaces for both the second-order unitary coupled cluster method and its perturbative approximation. Furthermore, the redundancies of the excitation operators are addressed in a novel way, which is potentially more efficient compared to the usual full diagonalization of the metric of the excited configurations. Despite the loss of rigorous size-extensivity possibly due to the use of a variational approach rather than a projective one in the solution of the amplitudes, test calculations show that the size-extensivity errors are very small. Compared to other internally contracted multireference perturbation theories, MRUPT2 only needs reduced density matrices up to three-body even with a non-complete active space reference wave function when two-body excitations within the active orbital subspace are involved in the wave operator, exp (G). Both the coupled cluster and perturbation theory variants are amenable to large, incomplete model spaces. Applications to some widely studied model systems that can be problematic because of geometry dependent quasidegeneracy, H4, P4, and
[Microsurgical 2nd toe transfer for catastrophic hand reconstruction].
Placer, A; Lozano, Ja
2007-01-01
The correct reconstruction of the catastrophic hand requires complex surgical techniques. The microsurgical transference of a toe is indicated when all other reconstructive options are shown to be useless for the reconstruction of the required clamp function. In this clinical note we set out the case of a 32 year old man, who came to our accident and emergency department after suffering a traffic accident. After exploration the diagnosis was that of catastrophic left hand, among other policontusions. Urgent surgery was carried out, saving the maximum possible viable structures. The immediate result of this surgery was a hand with 1st, 4th and 5th functional fingers. As the essential clamp function between the 1st and 4th or 5th fingers was not totally satisfactory, we decided to reconstruct the 3rd finger of his hand with his ipsilateral 2nd toe. All pertinent studies to determine vascularisation of the flap were carried out in planning the surgery, and the microsurgical transfer was then realized, which was successful. Today, after a suitable rehabilitation, the patient has recovered a satisfactory function of heavy and fine clamp in the operated hand. Toe to hand transfer is a good option for finger reconstruction and its function. Rehabilitation is the key to functional recovery. PMID:18227902
2nd PEGS Annual Symposium on Antibodies for Cancer Therapy
Ho, Mitchell; Royston, Ivor; Beck, Alain
2012-01-01
The 2nd Annual Antibodies for Cancer Therapy symposium, organized again by Cambridge Healthtech Institute as part of the Protein Engineering Summit, was held in Boston, USA from April 30th to May 1st, 2012. Since the approval of the first cancer antibody therapeutic, rituximab, fifteen years ago, eleven have been approved for cancer therapy, although one, gemtuzumab ozogamicin, was withdrawn from the market. The first day of the symposium started with a historical review of early work for lymphomas and leukemias and the evolution from murine to human antibodies. The symposium discussed the current status and future perspectives of therapeutic antibodies in the biology of immunoglobulin, emerging research on biosimilars and biobetters, and engineering bispecific antibodies and antibody-drug conjugates. The tumor penetration session was focused on the understanding of antibody therapy using ex vivo tumor spheroids and the development of novel agents targeting epithelial junctions in solid tumors. The second day of the symposium discussed the development of new generation recombinant immunotoxins with low immunogenicity, construction of chimeric antigen receptors, and the proof-of-concept of ‘photoimmunotherapy’. The preclinical and clinical session presented antibodies targeting Notch signaling and chemokine receptors. Finally, the symposium discussed emerging technologies and platforms for therapeutic antibody discovery. PMID:22864478
Aging Studies of 2nd Generation BaBar RPCs
Band, H.R.; /SLAC
2007-09-25
The BaBar detector, operating at the PEPII B factory of the Stanford Linear Accelerator Center (SLAC), installed over 200 2nd generation Resistive Plate Chambers (RPCs) in 2002. The streamer rates produced by backgrounds and signals from normal BaBar running vary considerably (0.1- >20 Hz/cm2) depending on the layer and position of the chambers, thus providing a broad spectrum test of RPC performance and aging. The lowest rate chambers have performed very well with stable efficiencies averaging 95%. Other chambers had rate-dependant inefficiencies due to Bakelite drying which were reversed by the introduction of humidified gases. RPC inefficiencies in the highest rate regions of the higher rate chambers have been observed and also found to be rate dependant. The inefficient regions grow with time and have not yet been reduced by operation with humidified input gas. Three of these chambers were converted to avalanche mode operation and display significantly improved efficiencies. The rate of production of HF in the RPC exhaust gases was measured in avalanche and streamer mode RPCs and found to be comparable despite the lower current of the avalanche mode RPCs.
PREFACE: 2nd International Symposium "Optics and its Applications"
NASA Astrophysics Data System (ADS)
Calvo, Maria L.; Dolganova, Irina N.; Gevorgyan, Narine; Guzman, Angela; Papoyan, Aram; Sarkisyan, Hayk; Yurchenko, Stanislav
2016-01-01
The ICTP smr2633: 2nd International Symposium "Optics and its Applications" (OPTICS-2014) http://indico.ictp.it/event/a13253/ was held in Yerevan and Ashtarak, Armenia, on 1-5 September 2014. The Symposium was organized by the Abdus Salam International Center for Theoretical Physics (ICTP) with the collaboration of the SPIE Armenian Student Chapter, the Armenian TC of ICO, the Russian-Armenian University (RAU), the Institute for Physical Research of the National Academy of Sciences of Armenia (IPR of NAS), the Greek-Armenian industrial company LT-Pyrkal, and the Yerevan State University (YSU). The Symposium was co-organized by the BMSTU SPIE & OSA student chapters. The International Symposium OPTICS-2014 was dedicated to the 50th anniversary of the Abdus Salam International Center for Theoretical Physics. This symposium "Optics and its Applications" was the First Official ICTP Scientific Event in Armenia. The presentations at OPTICS-2014 were centered on these topics: optical properties of nanostructures; quantum optics & information; singular optics and its applications; laser spectroscopy; strong field optics; nonlinear & ultrafast optics; photonics & fiber optics; optics of liquid crystals; and mathematical methods in optics.
APTWG: 2nd Asia-Pacific Transport Working Group Meeting
NASA Astrophysics Data System (ADS)
Dong, J. Q.; Shi, Y. J.; Tamura, N.; Jhang, Hogun; Watanabe, T.-H.; Ding, X. T.
2013-02-01
This conference report summarizes the contributions to and discussions at the 2nd Asia-Pacific Transport Working Group Meeting held in Chengdu, China, from 15 to 18 May 2012. The topics of the meeting were organized under five main headings: momentum transport, non-locality in transport, edge turbulence and L-H transition, three-dimensional effects on transport physics, and particle, momentum and heat pinches. It is found that lower hybrid wave and ion cyclotron wave induce co-current rotation while electron cyclotron wave induces counter-current rotation. A four-stage imaging for low (L) to high (H) confinement transition gradually emerges and a more detailed verification is urgently expected. The new edge-localized modes mitigation technique with supersonic molecular beam injection was approved to be effective to some extent on HL-2A and KSTAR. It is also found that low collisionality, trapped electron mode to ion temperature gradient transition (or transition of higher to lower density and temperature gradients), fuelling and lithium coating are in favour of inward pinch of particles in tokamak plasmas.
NASA Astrophysics Data System (ADS)
Weiss, T.; Mesch, M.; Schäferling, M.; Giessen, H.; Langbein, W.; Muljarov, E. A.
2016-06-01
We present a first-order perturbation theory to calculate the frequency shift and linewidth change of photonic resonances in one- and two-dimensional periodic structures under modifications of the surrounding refractive index. Our method is based on the resonant state expansion, for which we extend the analytical mode normalization to periodic structures. We apply this theory to calculate the sensitivity of bright dipolar and much darker quadrupolar plasmonic modes by determining the maximum shift and optimal sensing volume.
Weiss, T; Mesch, M; Schäferling, M; Giessen, H; Langbein, W; Muljarov, E A
2016-06-10
We present a first-order perturbation theory to calculate the frequency shift and linewidth change of photonic resonances in one- and two-dimensional periodic structures under modifications of the surrounding refractive index. Our method is based on the resonant state expansion, for which we extend the analytical mode normalization to periodic structures. We apply this theory to calculate the sensitivity of bright dipolar and much darker quadrupolar plasmonic modes by determining the maximum shift and optimal sensing volume. PMID:27341256
NASA Astrophysics Data System (ADS)
Shen, Jianhe; Han, Maoan
2014-08-01
This paper considers the existence and uniformly valid asymptotic approximation of canard solutions in a second-order nonlinear singularly perturbed boundary value problem with a turning point. We get the main results by constructing the asymptotic solution first and then defining a couple of upper and lower solutions suitably on the basis of the asymptotic solution. Two examples are carried out to illustrate and verify the theoretical results.
Highlights of the 2 nd Bioinformatics Student Symposium by ISCB RSG-UK
White, Benjamen; Fatima, Vayani; Fatima, Nazeefa; Das, Sayoni; Rahman, Farzana; Hassan, Mehedi
2016-01-01
Following the success of the 1 st Student Symposium by ISCB RSG-UK, a 2 nd Student Symposium took place on 7 th October 2015 at The Genome Analysis Centre, Norwich, UK. This short report summarizes the main highlights from the 2 nd Bioinformatics Student Symposium. PMID:27239284
Examples to Accompany "Descriptive Cataloging of Rare Books, 2nd Edition."
ERIC Educational Resources Information Center
Association of Coll. and Research Libraries, Chicago, IL.
This book is intended to be used with "Descriptive Cataloging of Rare Books," 2nd edition (DCRB) as an illustrative aid to catalogers and others interested in or needing to interpret rare book cataloging. As such, it is to be used in conjunction with the rules it illustrates, both in DCRB and in "Anglo-American Cataloging Rules," 2nd edition…
Development of a Hydrologic Characterization Technology for Fault Zones Phase II 2nd Report
Karasaki, Kenzi; Doughty, Christine; Gasperikova, Erika; Peterson, John; Conrad, Mark; Cook, Paul; Tiemi, Onishi
2011-03-31
This is the 2nd report on the three-year program of the 2nd phase of the NUMO-LBNL collaborative project: Development of Hydrologic Characterization Technology for Fault Zones under NUMO-DOE/LBNL collaboration agreement. As such, this report is a compendium of the results by Kiho et al. (2011) and those by LBNL.
PREFACE: 2nd National Conference on Nanotechnology 'NANO 2008'
NASA Astrophysics Data System (ADS)
Czuba, P.; Kolodziej, J. J.; Konior, J.; Szymonski, M.
2009-03-01
This issue of Journal of Physics: Conference Series contains selected papers presented at the 2nd National Conference on Nanotechnology 'NANO2008', that was held in Kraków, Poland, 25-28 June 2008. It was organized jointly by the Polish Chemical Society, Polish Physical Society, Polish Vacuum Society, and the Centre for Nanometer-scale Science and Advanced Materials (NANOSAM) of the Jagiellonian University. The meeting presentations were categorized into the following topics: 1. Nanomechanics and nanotribology 2. Characterization and manipulation in nanoscale 3. Quantum effects in nanostructures 4. Nanostructures on surfaces 5. Applications of nanotechnology in biology and medicine 6. Nanotechnology in education 7. Industrial applications of nanotechnology, presentations of the companies 8. Nanoengineering and nanomaterials (international sessions shared with the fellows of Maria-Curie Host Fellowships within the 6th FP of the European Community Project 'Nano-Engineering for Expertise and Development, NEED') 9. Nanopowders 10. Carbon nanostructures and nanosystems 11. Nanoelectronics and nanophotonics 12. Nanomaterials in catalysis 13. Nanospintronics 14. Ethical, social, and environmental aspects of nanotechnology The Conference was attended by 334 participants. The presentations were delivered as 7 invited plenary lectures, 25 invited topical lectures, 78 oral and 108 poster contributions. Only 1/6 of the contributions presented during the Conference were submitted for publication in this Proceedings volume. From the submitted material, this volume of Journal of Physics: Conference Series contains 37 articles that were positively evaluated by independent referees. The Organizing Committee gratefully acknowledges all these contributions. We also thank all the referees of the papers submitted for the Proceedings for their timely and thorough work. We would like to thank all members of the National Program Committee for their work in the selection process of
2nd interface between ecology and land development in California
Keeley, Jon E.; Baer-Keeley, Melanie; Fortheringham, C.J.
2000-01-01
The 2nd Interface Between Ecology and Land Development Conference was held in association with Earth Day 1997, five years after the first Interface Conference. Rapid population growth in California has intensified the inevitable conflict between land development and preservation of natural ecosystems. Sustainable development requires wise use of diminishing natural resources and, where possible, restoration of damaged landscapes. These Earth Week Celebrations brought together resource managers, scientists, politicians, environmental consultants, and concerned citizens in an effort to improve the communication necessary to maintain our natural biodiversity, ecosystem processes and general quality of life. As discussed by our keynote speaker, Michael Soule, the best predictor of habitat loss is population growth and nowhere is this better illustrated than in California. As urban perimeters expand, the interface between wildlands and urban areas increases. Few problems are more vexing than how to manage the fire prone ecosystems indigenous to California at this urban interface. Today resource managers face increasing challenges of dealing with this problem and the lead-off section of the proceedings considers both the theoretical basis for making decisions related to prescribed burning and the practical application. Habitat fragmentation is an inevitable consequence of development patterns with significant impacts on animal and plant populations. Managers must be increasingly resourceful in dealing with problems of fragmentation and the often inevitable consequences, including susceptibility to invasive oganisms. One approach to dealing with fragmentation problems is through careful landplanning. California is the national leader in the integration of conservation and economics. On Earth Day 1991, Governor Pete Wilson presented an environmental agenda that promised to create between land owners and environmentalists, agreements that would guarantee the protection of
NASA Astrophysics Data System (ADS)
Jansing, C.; Mertins, H. C.; Gaupp, A.; Sokolov, A.; Gilbert, M. C.; Wahab, H.; Timmers, H.
2016-05-01
Reflectivity measurements on graphitic materials such as graphene at energies across the carbon K-edge are frustrated by significant intensity loss due to adventitious carbon on beamline mirrors. Such intensity reduction enhances effects due to perturbing high-order harmonics in the beam. These effects distort the actual structure of the reflectance curve. In order to overcome this limitation, a correction technique has been developed and demonstrated first with measurements for highly ordered pyrolytic graphite. The same approach may be applied to other graphitic materials such as graphene and it may be used with other synchrotron beamlines. The fraction of high-order harmonics was determined by passing the incident beam through a 87 nm thin silicon nitride absorber that can be well modeled. Using the corrected measurements the x-ray natural linear dichroism of the sample has been determined.
Huang, Yuanhang; Beran, Gregory J. O.
2015-07-28
Three-body and higher intermolecular interactions can play an important role in molecular condensed phases. Recent benchmark calculations found problematic behavior for many widely used density functional approximations in treating 3-body intermolecular interactions. Here, we demonstrate that the combination of second-order Møller-Plesset (MP2) perturbation theory plus short-range damped Axilrod-Teller-Muto (ATM) dispersion accurately describes 3-body interactions with reasonable computational cost. The empirical damping function used in the ATM dispersion term compensates both for the absence of higher-order dispersion contributions beyond the triple-dipole ATM term and non-additive short-range exchange terms which arise in third-order perturbation theory and beyond. Empirical damping enables this simple model to out-perform a non-expanded coupled Kohn-Sham dispersion correction for 3-body intermolecular dispersion. The MP2 plus ATM dispersion model approaches the accuracy of O(N{sup 6}) methods like MP2.5 or even spin-component-scaled coupled cluster models for 3-body intermolecular interactions with only O(N{sup 5}) computational cost.
PREFACE: 2nd Workshop on Germanium Detectors and Technologies
NASA Astrophysics Data System (ADS)
Abt, I.; Majorovits, B.; Keller, C.; Mei, D.; Wang, G.; Wei, W.
2015-05-01
The 2nd workshop on Germanium (Ge) detectors and technology was held at the University of South Dakota on September 14-17th 2014, with more than 113 participants from 8 countries, 22 institutions, 15 national laboratories, and 8 companies. The participants represented the following big projects: (1) GERDA and Majorana for the search of neutrinoless double-beta decay (0νββ) (2) SuperCDMS, EDELWEISS, CDEX, and CoGeNT for search of dark matter; (3) TEXONO for sub-keV neutrino physics; (4) AGATA and GRETINA for gamma tracking; (5) AARM and others for low background radiation counting; (5) as well as PNNL and LBNL for applications of Ge detectors in homeland security. All participants have expressed a strong desire on having better understanding of Ge detector performance and advancing Ge technology for large-scale applications. The purpose of this workshop was to leverage the unique aspects of the underground laboratories in the world and the germanium (Ge) crystal growing infrastructure at the University of South Dakota (USD) by brining researchers from several institutions taking part in the Experimental Program to Stimulate Competitive Research (EPSCoR) together with key leaders from international laboratories and prestigious universities, working on the forefront of the intensity to advance underground physics focusing on the searches for dark matter, neutrinoless double-beta decay (0νββ), and neutrino properties. The goal of the workshop was to develop opportunities for EPSCoR institutions to play key roles in the planned world-class research experiments. The workshop was to integrate individual talents and existing research capabilities, from multiple disciplines and multiple institutions, to develop research collaborations, which includes EPSCor institutions from South Dakota, North Dakota, Alabama, Iowa, and South Carolina to support multi-ton scale experiments for future. The topic areas covered in the workshop were: 1) science related to Ge
VIEW SOUTH/SOUTHEAST LOOKING DOWN ON 2ND AQUEDUCT AND 1ST AQUEDUCT ...
VIEW SOUTH/SOUTHEAST LOOKING DOWN ON 2ND AQUEDUCT AND 1ST AQUEDUCT CASCADES TOWARDS FILTRATION PLANT AND LOS ANGELES RESERVOIR - Los Angeles Aqueduct, Cascades Structures, Los Angeles, Los Angeles County, CA
MAGAZINE E30. VIEW FROM BETWEEN 1ST AND 2ND BLAST WALL ...
MAGAZINE E-30. VIEW FROM BETWEEN 1ST AND 2ND BLAST WALL LOOKING TO THE REAR OF THE MAGAZINE. - Naval Magazine Lualualei, Waikele Branch, Tunnel Magazine Type, Waikakalaua & Kipapa Gulches, Pearl City, Honolulu County, HI
22. MILL NO. 1, 2nd FLOOR, LIGHT TABLES AND KNITTING ...
22. MILL NO. 1, 2nd FLOOR, LIGHT TABLES AND KNITTING MACHINE. LIGHT TABLE USED TO CHECK FOR CLOTH DEFECTS. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL
12. Bldg #13, 2nd floor, interior stone walls w/windows and ...
12. Bldg #13, 2nd floor, interior stone walls w/windows and bent pipe thru wall L and light bulbs in ceiling, to NE - Lawrence Machine Shop, Building No. 13, Union & Canal Streets, Lawrence, Essex County, MA
4. VIEW WEST, WEST SIDE, SHOWING CHANNELS 1ST AND 2ND ...
4. VIEW WEST, WEST SIDE, SHOWING CHANNELS 1ST AND 2ND VERTICAL BRACED DOUBLE ANGLES, DIAGONAL BRACING AND CROSS BRACED RAILING - Thirty-Sixth Street Bridge, Spanning Rabbit River, Hamilton, Allegan County, MI
2nd U.S. Case of Bacteria Resistant to Last-Resort Antibiotic
... news/fullstory_159807.html 2nd U.S. Case of Bacteria Resistant to Last-Resort Antibiotic Scientists concerned it ... the United States who was infected with a bacteria that is resistant to an antibiotic of last ...
Front elevation of Rostrum with 2nd Division American Expeditionary Force ...
Front elevation of Rostrum with 2nd Division American Expeditionary Force Monument in foreground, view to northwest - Cypress Hills National Cemetery, Jamaica Avenue Unit, 625 Jamaica Avenue, Brooklyn, Kings County, NY
37. MILL NO. 2, 2nd FLOOR, CLOSE SHOT OF 2 ...
37. MILL NO. 2, 2nd FLOOR, CLOSE SHOT OF 2 CREEL MACHINES, WHICH FEED YARN INTO KNITTING MACHINES. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL
73. VIEW OF NORTHWEST SIDE OF 2ND TEE, LOOKING NORTHWEST, ...
73. VIEW OF NORTHWEST SIDE OF 2ND TEE, LOOKING NORTHWEST, SHOWING STEPPED PLATFORM, BENCHES, AND LIGHT STANDARDS - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA
21. VIEW FROM INTERIOR OF 2ND FLOOR ARCHED WINDOW WITH ...
21. VIEW FROM INTERIOR OF 2ND FLOOR ARCHED WINDOW WITH HOLLOW STEEL SASH AND POLISHED PLATE WIRE GLASS. THIS WINDOW IS AT THE FRONT OF THE BUILDING. - Pacific Telephone & Telegraph Company Building, 1519 Franklin Street, Oakland, Alameda County, CA
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2012-09-04
... Countervailing Duty Orders; Policy Bulletin, 63 FR 18871 (April 16, 1998). The Notice of Initiation of Five-Year...) Dana Mermelstein (202) (2nd Review). 482-1391 Silicomanganese from Venezuela (A-307-820) (2nd...
Krasnoshchekov, Sergey V.; Isayeva, Elena V.; Stepanov, Nikolay F.
2014-12-21
The second-order vibrational Hamiltonian of a semi-rigid polyatomic molecule when resonances are present can be reduced to a quasi-diagonal form using second-order vibrational perturbation theory. Obtaining exact vibrational energy levels requires subsequent numerical diagonalization of the Hamiltonian matrix including the first- and second-order resonance coupling coefficients. While the first-order Fermi resonance constants can be easily calculated, the evaluation of the second-order Darling-Dennison constants requires more complicated algebra for seven individual cases with different numbers of creation-annihilation vibrational quanta. The difficulty in precise evaluation of the Darling-Dennison coefficients is associated with the previously unrecognized interference with simultaneously present Fermi resonances that affect the form of the canonically transformed Hamiltonian. For the first time, we have presented the correct form of the general expression for the evaluation of the Darling-Dennison constants that accounts for the underlying effect of Fermi resonances. The physically meaningful criteria for selecting both Fermi and Darling-Dennison resonances are discussed and illustrated using numerical examples.
Su, Neil Qiang; Xu, Xin
2016-05-10
Recently, we have developed an integration approach for the calculations of ionization potentials (IPs) and electron affinities (EAs) of molecular systems at the level of second-order Møller-Plesset (MP2) (Su, N. Q.; Xu, X. J. Chem. Theory Comput. 11, 4677, 2015), where the full MP2 energy gradient with respect to the orbital occupation numbers was derived but only at integer occupations. The theory is completed here to cover the fractional occupation systems, such that Slater's transition state concept can be used to have accurate predictions of IPs and EAs. Antisymmetrized Goldstone diagrams have been employed for interpretations and better understanding of the derived equations, where two additional rules were introduced in the present work specifically for hole or particle lines with fractional occupation numbers. PMID:27010405
Transient 2(nd) Degree Av Block Mobitz Type II: A Rare Finding in Dengue Haemorrhagic Fever.
Nigam, Ashwini Kumar; Singh, Omkar; Agarwal, Ayush; Singh, Amit K; Yadav, Subhash
2015-05-01
Dengue has been a major problem as endemic occurs almost every year and causes a state of panic due to lack of proper diagnostic methods and facilities for proper management. Patients presenting with classical symptoms are easy to diagnose, however as a large number of cases occur every year, a number of cases diagnosed with dengue fever on occasion presents with atypical manifestations, which cause extensive evaluation of the patients, unnecessary referral to higher centre irrespective of the severity and therefore a rough idea of these manifestations must be present in the backdrop in order to prevent these problems. Involvement of cardiovascular system in dengue has been reported in previous studies, and they are usually benign and self-limited. The importance of study of conduction abnormalities is important as sometimes conduction blocks are the first sign of acute myocarditis in patients of Dengue Hemorrhagic Fever in shock. We present here a case of 2(nd) Degree Mobitz Type II atrioventricular AV block in a case of Dengue Hemorrhagic fever reverting to the normal rhythm in recovery phase and no signs thereafter on follow up. PMID:26155512
Tabrizi, Shadan Ghassemi; Arbuznikov, Alexei V; Kaupp, Martin
2016-05-10
A general giant-spin Hamiltonian (GSH) describing an effective spin multiplet of an exchange-coupled metal cluster with dominant Heisenberg interactions was derived from a many-spin Hamiltonian (MSH) by treating anisotropic interactions at the third order of perturbation theory. Going beyond the existing second-order perturbation treatment allows irreducible tensor operators of rank six (or corresponding Stevens operator equivalents) in the GSH to be obtained. Such terms were found to be of crucial importance for the fitting of high-field EPR spectra of a number of single-molecule magnets (SMMs). Also, recent magnetization measurements on trigonal and tetragonal SMMs have found the inclusion of such high-rank axial and transverse terms to be necessary to account for experimental data in terms of giant-spin models. While mixing of spin multiplets by local zero-field splitting interactions was identified as the major origin of these contributions to the GSH, a direct and efficient microscopic explanation had been lacking. The third-order approach developed in this work is used to illustrate the mapping of an MSH onto a GSH for an S=6 trigonal Fe3 Cr complex that was recently investigated by high-field EPR spectroscopy. Comparisons between MSH and GSH consider the simulation of EPR data with both Hamiltonians, as well as locations of diabolical points (conical intersections) in magnetic-field space. The results question the ability of present high-field EPR techniques to determine high-rank zero-field splitting terms uniquely, and lead to a revision of the experimental GSH parameters of the Fe3 Cr SMM. Indeed, a bidirectional mapping between MSH and GSH effectively constrains the number of free parameters in the GSH. This notion may in the future facilitate spectral fitting for highly symmetric SMMs. PMID:27062248
Nagata, Takeshi; Fedorov, Dmitri G; Li, Hui; Kitaura, Kazuo
2012-05-28
A new energy expression is proposed for the fragment molecular orbital method interfaced with the polarizable continuum model (FMO/PCM). The solvation free energy is shown to be more accurate on a set of representative polypeptides with neutral and charged residues, in comparison to the original formulation at the same level of the many-body expansion of the electrostatic potential determining the apparent surface charges. The analytic first derivative of the energy with respect to nuclear coordinates is formulated at the second-order Møller-Plesset (MP2) perturbation theory level combined with PCM, for which we derived coupled perturbed Hartree-Fock equations. The accuracy of the analytic gradient is demonstrated on test calculations in comparison to numeric gradient. Geometry optimization of the small Trp-cage protein (PDB: 1L2Y) is performed with FMO/PCM/6-31(+)G(d) at the MP2 and restricted Hartree-Fock with empirical dispersion (RHF/D). The root mean square deviations between the FMO optimized and NMR experimental structure are found to be 0.414 and 0.426 Å for RHF/D and MP2, respectively. The details of the hydrogen bond network in the Trp-cage protein are revealed. PMID:22667545
Pandit, Anjali; Wawrzyniak, Piotr K; van Gammeren, Adriaan J; Buda, Francesco; Ganapathy, Swapna; de Groot, Huub J M
2010-01-26
Protein nuclear magnetic resonance (NMR) secondary chemical shifts are widely used to predict the secondary structure, and in solid-state NMR, they are often the only unambiguous structural parameters available. However, the employed prediction methods are empirical in nature, relying on the assumption that secondary shifts are only affected by shielding effects of neighboring atoms. We analyzed the secondary shifts of a photosynthetic membrane protein with a high density of chromophores and very tight packing, the light-harvesting 2 (LH2) complex of Rhodopseudomonas acidophila. A relation was found between secondary shift anomalies and protein-protein or pigment-protein tertiary and quaternary contacts. For several residues, including the bacteriochlorophyll-coordinating histidines (alphaH31 and betaH30) and the phenylalanine alphaF41 that has strongly twisted C(b)-C(a)-C and C(a)-C-N conformations in the LH2 crystal structure, the perturbing effects on the backbone chemical shifts were tested by density functional theory (DFT) calculations. We propose that higher-order interactions in the tightly packed complex can induce localized perturbations of the backbone conformation and electronic structure, related to functional pigment-protein or protein-protein interactions. PMID:19954238
Budyak, Ivan L; Doyle, Brandon L; Weiss, William F
2015-04-01
Robust higher order structure (HOS) characterization capability and strategy are critical throughout biopharmaceutical development from initial candidate selection and formulation screening to process optimization and manufacturing. This case study describes the utility of several orthogonal HOS methods as investigational tools during purification process development. An atypically high level of residual detergent in a development drug substance batch of a therapeutic monoclonal antibody triggered a root cause investigation. Several orthogonal biophysical techniques were used to uncover and characterize a specific interaction between the detergent and the antibody. Isothermal titration calorimetry (ITC) was used to quantify the molar ratio and affinity of the binding event, and circular dichroism (CD) spectroscopy and differential scanning calorimetry (DSC) were used to evaluate corresponding impacts on secondary/tertiary structure and thermal stability, respectively. As detergents are used routinely in biopharmaceutical processing, this case study highlights the value and power of HOS data in informing technical investigations and underlines the importance of HOS characterization as a component of overall biopharmaceutical analytical control strategy. PMID:25545760
NASA Astrophysics Data System (ADS)
Phillips, Jordan J.; Zgid, Dominika
2014-06-01
We report an implementation of self-consistent Green's function many-body theory within a second-order approximation (GF2) for application with molecular systems. This is done by iterative solution of the Dyson equation expressed in matrix form in an atomic orbital basis, where the Green's function and self-energy are built on the imaginary frequency and imaginary time domain, respectively, and fast Fourier transform is used to efficiently transform these quantities as needed. We apply this method to several archetypical examples of strong correlation, such as a H32 finite lattice that displays a highly multireference electronic ground state even at equilibrium lattice spacing. In all cases, GF2 gives a physically meaningful description of the metal to insulator transition in these systems, without resorting to spin-symmetry breaking. Our results show that self-consistent Green's function many-body theory offers a viable route to describing strong correlations while remaining within a computationally tractable single-particle formalism.
Phillips, Jordan J. Zgid, Dominika
2014-06-28
We report an implementation of self-consistent Green's function many-body theory within a second-order approximation (GF2) for application with molecular systems. This is done by iterative solution of the Dyson equation expressed in matrix form in an atomic orbital basis, where the Green's function and self-energy are built on the imaginary frequency and imaginary time domain, respectively, and fast Fourier transform is used to efficiently transform these quantities as needed. We apply this method to several archetypical examples of strong correlation, such as a H{sub 32} finite lattice that displays a highly multireference electronic ground state even at equilibrium lattice spacing. In all cases, GF2 gives a physically meaningful description of the metal to insulator transition in these systems, without resorting to spin-symmetry breaking. Our results show that self-consistent Green's function many-body theory offers a viable route to describing strong correlations while remaining within a computationally tractable single-particle formalism.
Acid soil and acid rain, 2nd edition
Kennedy, I.R.
1992-01-01
This book examines the basic chemical processes involved in acidification in order to better assess their long-term effects on the status of soils, the health of plants and other living species that depend on them. It also discusses acidity, pH and protons their significance in bioenergetics and the consequent role of autotrophic organisms in acidifying ecosystems. This edition incorporates and integrates recent findings that render more explanations of the causes of the environmental impacts of acidity, especially in forests and lakes. Also explores current research into acid rain and soil in order to devise appropriate measures for their amelioration.
Writing II for 2nd Year EFL Student Teachers
ERIC Educational Resources Information Center
Abdallah, Mahmoud M. S.
2015-01-01
Writing is a very important skill that should be mastered properly by university students, especially pre-service language teachers (e.g. EFL student teachers). In order to present their ideas efficiently in the context of their academic study, they have to be trained well on how to write meaningful pieces (e.g. essays, academic reports,…
NASA Astrophysics Data System (ADS)
Bozkaya, Uǧur
2011-12-01
In this research, orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) and its spin-component and spin-opposite scaled variants (SCS-OMP3 and SOS-OMP3) are introduced. Using a Lagrangian-based approach, an efficient, quadratically convergent algorithm for variational optimization of the molecular orbitals (MOs) for third-order Møller-Plesset perturbation theory (MP3) is presented. Explicit equations for response density matrices, the MO gradient, and Hessian are reported in spin-orbital form. The OMP3, SCS-OMP3, and SOS-OMP3 approaches are compared with the second-order Møller-Plesset perturbation theory (MP2), MP3, coupled-cluster doubles (CCD), optimized-doubles (OD), and coupled-cluster singles and doubles (CCSD) methods. All these methods are applied to the O4 +, O3, and seven diatomic molecules. Results demonstrate that the OMP3 and its variants provide significantly better vibrational frequencies than MP3, CCSD, and OD for the molecules where the symmetry-breaking problems are observed. For O4 +, the OMP3 prediction, 1343 cm-1, for ω6 (b3u) mode, where symmetry-breaking appears, is even better than presumably more reliable methods such as Brueckner doubles (BD), 1194 cm-1, and OD, 1193 cm-1, methods (the experimental value is 1320 cm-1). For O3, the predictions of SCS-OMP3 (1143 cm-1) and SOS-OMP3 (1165 cm-1) are remarkably better than the more robust OD method (1282 cm-1); the experimental value is 1089 cm-1. For the seven diatomics, again the SCS-OMP3 and SOS-OMP3 methods provide the lowest average errors, |Δωe| = 44 and |Δωe| = 35 cm-1, respectively, while for OD, |Δωe| = 161 cm-1and CCSD |Δωe| = 106 cm-1. Hence, the OMP3 and especially its spin-scaled variants perform much better than the MP3, CCSD, and more robust OD approaches for considered test cases. Therefore, considering both the computational cost and the reliability, SCS-OMP3 and SOS-OMP3 appear to be the best methods for the symmetry-breaking cases, based on
NASA Astrophysics Data System (ADS)
Ito, T. U.; Higemoto, W.; Sakai, A.; Tsujimoto, M.; Nakatsuji, S.
2015-09-01
The nature of multipolar order and hyperfine-enhanced (HE) 141Pr nuclear spin dynamics in PrV2Al20 was investigated using the muon spin relaxation technique. No explicit sign of time-reversal symmetry breaking was found below the multipolar order temperature TQ˜0.6 K in a zero applied field as anticipated on the basis of the antiferroquadrupolar (AFQ) order picture proposed by Sakai and Nakatsuji [J. Phys. Soc. Jpn. 80, 063701 (2011), 10.1143/JPSJ.80.063701]. Further evidence of the nonmagnetic ground state was obtained from the observation of HE 141Pr nuclear spin fluctuations in the MHz scale. A marked increase in the muon spin-lattice relaxation rate (1 /T1 ,μ) was observed below 1 K with decreasing temperature, which was attributed to the perturbation on the HE 141Pr nuclear spin dynamics associated with the development of AFQ correlations. The longitudinal field dependence of 1 /T1 ,μ revealed that the enhanced 141Pr nuclear spin accidentally has an effective gyromagnetic ratio close to that of the muon.
Radionuclide and radiation protection data handbook 2nd edition (2002).
Delacroix, D; Guerre, J P; Leblanc, P; Hickman, C
2002-01-01
This handbook is a reference source of radionuclide and radiation protection information. Its purpose is to provide users of radionuclides in medicine, research and industry with consolidated and appropriate information and data to handle and transport radioactive substances safely. It is mainly intended for users in low and intermediate activity laboratories. Individual data sheets are provided for a wide range of commonly used radionuclides (144 in total). These radionuclides are classified into five different groups as a function of risk level, represented by colours red, orange, yellow, green and blue, in descending order of risk. PMID:11916063
The Beta Pictoris Circumstellar Disk (5202; 2ND Visit)
NASA Astrophysics Data System (ADS)
Trauger, John
1994-01-01
We propose new methods to examine the circumstellar disk around Beta Pictoris in order to determine its radial profile, and hence (in combination with IRAS data) to fix its albedo and temperature profile. These observations will extend previous extensive ground based coronagraphic observations, and models by members of the science team. The data will enable us to understand better the central clearing in the disk and whether it is caused by sublimation or possible planet formation. They will also constrain the geometric propertie of the disk including its inclination angle, vertical thickness and radial profile. Such observations limit models for the dynamics of the disk, includin its velocity dispersion and hence mass distribution, and radial mass transport mechanisms. If density waves or clear zones are observed, they will give indirect evidence for the presence of massive bodies (planets) in the disk. Th observations involve a combination of roll deconvolution, polarizers and PSF modelling in order to allow the central stellar image and associated scattered light to be subtracted. Ultraviolet observations will constrain the particle size distribution and the composition of the disk. The observations require the new capabilities in WFPC2 provided by the absence of bleeding across columns, as well as its UV capabilities.
A compendium of fossil marine animal families, 2nd edition
NASA Technical Reports Server (NTRS)
Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)
1992-01-01
A comprehensive listing of 4075 taxonomic families of marine animals known from the fossil record is presented. This listing covers invertebrates, vertebrates, and animal-like protists, gives time intervals of apparent origination and extinction, and provides literature sources for these data. The time intervals are mostly 81 internationally recognized stratigraphic stages; more than half of the data are resolved to one of 145 substage divisions, providing more highly resolved data for studies of taxic macroevolution. Families are classified by order, class, and phylum, reflecting current classifications in the published literature. This compendium is a new edition of the 1982 publication, correcting errors and presenting greater stratigraphic resolution and more current ideas about acceptable families and their classification.
A compendium of fossil marine animal families, 2nd edition.
Sepkoski, J J
1992-03-01
A comprehensive listing of 4075 taxonomic families of marine animals known from the fossil record is presented. This listing covers invertebrates, vertebrates, and animal-like protists, gives time intervals of apparent origination and extinction, and provides literature sources for these data. The time intervals are mostly 81 internationally recognized stratigraphic stages; more than half of the data are resolved to one of 145 substage divisions, providing more highly resolved data for studies of taxic macroevolution. Families are classified by order, class, and phylum, reflecting current classifications in the published literature. This compendium is a new edition of the 1982 publication, correcting errors and presenting greater stratigraphic resolution and more current ideas about acceptable families and their classification. PMID:11542296
Regional Observations of North Korea Explosions: 1st and 2nd Tests
NASA Astrophysics Data System (ADS)
Chi, Heon Cheol; Shin, Jin Soo; Lee, Hee-Il; Park, Jung Ho; Sheen, Dong-Hoon; Kim, Geunyoung; Kim, Tea Sung; Che, Il-Young; Lim, In-Seub
2010-05-01
Through data exchanging with China, Russia and Japan, KIGAM could monitor North Korea explosion tests in near real time with azimuthally full coverage from the test site. Except for the East Sea (Japan Sea) side, the seismic stations are distributed uniformly along the boundaries of North Korea and adjacent countries. The error ellipses of epicentral determination of test site for 1st and 2nd tests showed almost identical pattern if they were separately calculated with the same configuration of stations. But the combined use of the 1st and the 2nd test data showed that the 2nd test site was moved approximately 2 Km westward from 1st site. The Pn/Lg spectral ratio clearly discriminate these events from two nearby natural earthquakes above 4 Hz. Full moment tensor inversion also indicate the 2nd test had a very large isotropic component. But mb-Ms discrimination, which has been considered one of the most reliable discriminants for separating explosions and earthquakes, did not show apparently the known pattern of explosion for both tests. Body wave magnitude, mb(Pn) of the 2nd test, which was evaluated as 4.5 by KIGAM, varies with directional location of stations widely from 4.1 to 5.2. The magnitude obtained from Lg, mb(Lg), showed narrow variation between 4.3 to 4.7 with the average of 4.5. In the case of both 1st and 2nd tests, both mb(Pn) and mb(Lg) showed equivalently large variation with directional station location. These variations are mainly due to lateral variation of crustal structures surrounding the test site. Remarkably mb(Lg) showed very linear relationship with mb(Pn). By considering attenuation characteristics according to the propagation path, the variations could be effectively reduced. The cut-off frequencies of P wave of both tests showed no or negligible difference even though the estimated yield of the 2nd test were much larger than that of the 1st one. The ratio of P-wave amplitudes of two tests showed from 2 to 3.1 times. Correspondingly the
Monitoring North Korea Explosions: Status and Result of 1st and 2nd Tests (Invited)
NASA Astrophysics Data System (ADS)
Chi, H.; Lee, H.; Shin, J.; Park, J.; Sheen, D.; Kim, G.; Che, I.; Lim, I.; Kim, T.
2009-12-01
Through data exchanging with China, Russia and Japan, KIGAM could monitor North Korea explosion tests in near real time with azimuthal full coverage from the test site. Except for the East Sea (Japan Sea) side, the seismic stations are distributed uniformly along the boundaries of North Korea and adjacent countries, and only stations with the distance of 200 to 550 Km from the test site were considered. Irrespective of azimuthal directions of stations from the test site, the conventional discrimination, Pn/Lg spectral ratio clearly showed that both tests were explosion. But mb-Ms discrimination did not show apparently the known pattern of explosion for both tests. Body wave magnitude, mb(Pn) of 2nd test, which was evaluated as 4.5 by KIGAM, varies with directional location of stations widely from 4.1 to 5.2. The magnitude obtained from Lg, mb(Lg), showed narrow variation between 4.3 to 4.7 with the average of 4.5. In the case of 1st test, both mb(Pn) and mb(Lg) showed equivalently large variation with directional station location. The error ellipses of epicentral determination of test site for 1st and 2nd tests showed almost identical pattern if they were separately calculated with the same configuration of stations. But the combined use of 1st and 2nd test data showed that 2nd test site was moved approximately 2 Km westward from 1st site. The cut-off frequencies of P wave of 1st and 2nd tests showed no or negligible difference even though the estimated yield of 2nd test were much larger than that of 1st one. The ratio of 1st and 2nd P-wave amplitudes showed from 2 to 3.1 times. Correspondingly the estimated energy or yield were ranged from 4 to roughly 10 times. KIGAM evaluated the yield of 2nd test were 8 times in the average larger than that of 1st one.
An Introduction to Thermodynamics and Statistical Mechanics - 2nd Edition
NASA Astrophysics Data System (ADS)
Stowe, Keith
2003-03-01
This introductory textbook for standard undergraduate courses in thermodynamics has been completely rewritten. Starting with an overview of important quantum behaviours, the book teaches students how to calculate probabilities, in order to provide a firm foundation for later chapters. It introduces the ideas of classical thermodynamics and explores them both in general and as they are applied to specific processes and interactions. The remainder of the book deals with statistical mechanics - the study of small systems interacting with huge reservoirs. The changes to this second edition have been made after more than 10 years classroom testing and student feedback. Each topic ends with a boxed summary of ideas and results, and every chapter contains numerous homework problems, covering a broad range of difficulties. Answers are given to odd numbered problems, and solutions to even problems are available to instructors at www.cambridge.org/9780521865579. The entire book has been re-written and now covers more topics It has a greater number of homework problems which range in difficulty from warm-ups to challenges It is concise and has an easy reading style
Organic Chemistry, 2nd Edition (by Paula Y. Bruice)
NASA Astrophysics Data System (ADS)
Katz, Marlene G.
1998-11-01
Prentice Hall: Englewood Cliffs, NJ, 1998, xxx +1256 pp, 6 appendices. ISBN 0-13-841925-6. $99. The author has made some constructive changes to the second edition of this visually pleasing book. The chapter order has been rearranged so that all of spectroscopy is covered in two adjoining chapters (new problems combining NMR and IR have been added), all of the chapters on bioorganic chemistry are grouped together (information on reducing sugars has been added), and the last section now covers heterocycles, pericyclic reactions, polymer synthesis, multistep synthetic strategies, and drug design. The publisher offers additional material at its Web site and a paperback for students assisting them in using the Internet. The ChemCentral Organic Web site has problem sets to supplement each chapter (including hints for struggling students) and animations of molecules undergoing reactions. In addition the Web site provides syllabus construction software for instructors. The accompanying study guide/solutions manual, written by the textbook author, contains a glossary, answers to chapter problems, and a practice test (for the first twenty chapters). There are sections called "special topics" which offer in-depth treatment of pH, pKa, buffers, and the electron-pushing formalism.
Phung, Quan Manh; Wouters, Sebastian; Pierloot, Kristine
2016-09-13
The complete active space second order perturbation theory (CASPT2) can be extended to larger active spaces by using the density matrix renormalization group (DMRG) as solver. Two variants are commonly used: the costly DMRG-CASPT2 with exact 4-particle reduced density matrix (4-RDM) and the cheaper DMRG-cu(4)-CASPT2 in which the 4-cumulant is discarded. To assess the accuracy and limitations of the latter variant DMRG-cu(4)-CASPT2 we study the spin state energetics of iron porphyrin Fe(P) and its model compound FeL2, a model for the active center of NiFe hydrogenase, and manganese-oxo porphyrin MnO(P)(+); a series of excited states of chromium hexacarbonyl Cr(CO)6; and the interconversion of two Cu2O2(2+) isomers. Our results clearly show that PT2 on top of DMRG is essential in order to obtain quantitative results for transition metal complexes. Good results were obtained with DMRG-cu(4)-CASPT2 as compared to full CASPT2 and DMRG-CASPT2 in calculations with small- and medium-sized active spaces. In calculations with large-sized active spaces (∼30 active orbitals), the performance of DMRG-cu(4)-CASPT2 is less impressive due to the errors originating from both the finite number of renormalized states m and the 4-RDM approximation. PMID:27547847
NASA Astrophysics Data System (ADS)
Mendonça, T. M.; Correia, J. G.; Haas, H.; Odier, P.; Tavares, P. B.; da Silva, M. R.; Lopes, A. M. L.; Pereira, A. M.; Gonçalves, J. N.; Amaral, J. S.; Darie, C.; Araujo, J. P.
2011-09-01
Lattice sites and collective ordering of oxygen atoms in HgBa2CaCu2O6+δ were studied using the perturbed angular correlation (PAC) technique at ISOLDE/CERN. The electric field gradients (EFG) at 199mHg nuclei have been measured as functions of oxygen doping on the Hg planes, above and below Tc. In comparison with the results obtained for oxygen and fluorine doping in Hg-1201, the analysis shows a different oxygen ordering exhibited by Hg-1212. Moreover, for all studied cases, the experimental results show that at a local scale there is non uniform oxygen distribution. A series of ab initio EFG calculations allowed to infer that at low concentrations, regions without oxygen coexist with regions where O2δ dumbbell molecules are located at the center of the Hg mesh. On the other side, at high concentrations, O2δ dumbbell molecules coexist with single Oδ atoms occupying the center of the Hg mesh. The present results suggest that oxygen sits on the Hg planes in the form of a molecule and not as a single atom.
DOE performance indicators for 2nd quarter CY 1993
Not Available
1993-11-01
The Department of Energy (DOE) has established a Department-wide Performance Indicator (PI) Program for trending and analysis of operational data as directed by DOE Order 5480.26. The PI Program was established to provide a means for monitoring the environment, safety, and health (ES&H) performance of the DOE at the Secretary and other management levels. This is the tenth in a series of quarterly reports generated for the Department of Energy Idaho Operations Office (DOE-ID) by EG&G Idaho, Inc. to meet the requirements of the PI Program as directed by the DOE Standard (DOE-STD-1048-92). The information in this tenth quarterly report, while contributing to a historical database for supporting future trending analysis, does not at this time provide a sound basis for developing trend-related conclusions. In the future, it is expected that trending and analysis of operational data will enhance the safety culture in both DOE and contractor organizations by providing an early warning of deteriorating environment, safety, and health conditions. DOE-STD-1048-92 identifies four general areas of PIs. They are: Personnel Safety, Operational Incidents, Environment, and Management. These four areas have been subdivided into 26 performance indicators. Approximately 115 performance indicator control and distribution charts comprise the body of this report. A brief summary of PIs contained in each of these general areas is provided. The four EG&G facilities whose performance is charted herein are as follows: (1) The Advanced Test Reactor (ATR), (2) The Radioactive Waste Management Complex (RWMC), (3) The Waste Experimental Reduction Facility (WERF), and (4) The Test Reactor Area (TRA) Hot Cells.
NASA Astrophysics Data System (ADS)
Peskin, Michael E.
2011-04-01
and topology, and applications to condensed matter systems including the Peierls instability and the quantum Hall fluid. It is a large amount of territory to cover in a single volume. Few derivations are more than one page long. Those that fit in that space are very smooth, but others are too abbreviated to be fully comprehensible. The prose that accompanies the derivations, though, is always enticing. Zee misses no opportunity to point out that an argument he gives opens the door to some deeper subject that he encourages the reader to explore. I do warn students that it is easy to learn from this book how to talk quantum field theory without understanding it. To avoid this pitfall, it is important (as Zee emphasizes) to fill in the steps of his arguments with hard calculation. One topic from which Zee does not restrain himself is the quantum theory of gravity. In the first hundred pages we find a `concise introduction to curved spacetime' that includes a very pretty derivation of the Christoffel symbol from the geodesic equation. Toward the end of the book, there is a set of chapters devoted to the quantization of the gravitational field. The structure of the graviton propagator is worked out carefully. The van Dam-Veltman discontinuity between massless and massive spin 2 exchange is explained clearly. But after this Zee runs out of steam in presenting fully worked arguments. Still, there is room for more prose on connections to the great mysteries of the subject: the ultraviolet behavior, the cosmological constant, and the unification of forces. A new chapter added to the second edition discusses `Is Einstein Gravity The Square Of Yang-Mills Theory?' and suggests an affirmative answer, based on brand-new developments in perturbative quantum field theory. Quantum field theory is a large subject that still has not reached its definitive form. As such, there is room for many textbooks of complementary character. Zee states frankly, `It is not the purpose of this book
NASA Astrophysics Data System (ADS)
Peskin, Michael E.
2011-04-01
and topology, and applications to condensed matter systems including the Peierls instability and the quantum Hall fluid. It is a large amount of territory to cover in a single volume. Few derivations are more than one page long. Those that fit in that space are very smooth, but others are too abbreviated to be fully comprehensible. The prose that accompanies the derivations, though, is always enticing. Zee misses no opportunity to point out that an argument he gives opens the door to some deeper subject that he encourages the reader to explore. I do warn students that it is easy to learn from this book how to talk quantum field theory without understanding it. To avoid this pitfall, it is important (as Zee emphasizes) to fill in the steps of his arguments with hard calculation. One topic from which Zee does not restrain himself is the quantum theory of gravity. In the first hundred pages we find a `concise introduction to curved spacetime' that includes a very pretty derivation of the Christoffel symbol from the geodesic equation. Toward the end of the book, there is a set of chapters devoted to the quantization of the gravitational field. The structure of the graviton propagator is worked out carefully. The van Dam-Veltman discontinuity between massless and massive spin 2 exchange is explained clearly. But after this Zee runs out of steam in presenting fully worked arguments. Still, there is room for more prose on connections to the great mysteries of the subject: the ultraviolet behavior, the cosmological constant, and the unification of forces. A new chapter added to the second edition discusses `Is Einstein Gravity The Square Of Yang-Mills Theory?' and suggests an affirmative answer, based on brand-new developments in perturbative quantum field theory. Quantum field theory is a large subject that still has not reached its definitive form. As such, there is room for many textbooks of complementary character. Zee states frankly, `It is not the purpose of this book
Proceedings of the 2nd symposium on valves for coal conversion and utilization
Maxfield, D.A.
1981-01-01
The 2nd symposium on valves for coal conversion and utilization was held October 15 to 17, 1980. It was sponsored by the US Department of Energy, Morgantown Energy Technology Center, in cooperation with the Valve Manufacturers Association. Seventeen papers have been entered individually into EDB and ERA. (LTN)
This NERL-Cincinnati publication, “Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices - 2nd Edition” was prepared as the continuation of an initiative to gather together under a single cover a compendium of standardized laborato...
2nd International Forum for Surveillance and Control of Mosquitoes and Mosquito-borne Diseases
Technology Transfer Automated Retrieval System (TEKTRAN)
The Entomological Society of China (ESC) and Beijing Institute of Microbiology and Epidemiology (BIME) hosted the 2nd International Forum for Surveillance and Control of Mosquitoes and Mosquito-borne Diseases in Beijing, China, May 23-27, 2011. The theme of the Forum was “Impact of global climate ch...
Technical Adequacy of the Disruptive Behavior Rating Scale-2nd Edition--Self-Report
ERIC Educational Resources Information Center
Erford, Bradley T.; Miller, Emily M.; Isbister, Katherine
2015-01-01
This study provides preliminary analysis of the Disruptive Behavior Rating Scale-2nd Edition--Self-Report, which was designed to screen individuals aged 10 years and older for anxiety and behavior symptoms. Score reliability and internal and external facets of validity were good for a screening-level test.
Stem cells and cancer immunotherapy: Arrowhead’s 2nd annual cancer immunotherapy conference
2014-01-01
Investigators from academia and industry gathered on April 4 and 5, 2013, in Washington DC at the Arrowhead’s 2nd Annual Cancer Immunotherapy Conference. Two complementary concepts were discussed: cancer “stem cells” as targets and therapeutic platforms based on stem cells.
Evaluation of a Hand Washing Program for 2nd-Graders
ERIC Educational Resources Information Center
Tousman, Stuart; Arnold, Dani; Helland, Wealtha; Roth, Ruth; Heshelman, Nannatte; Castaneda, Oralia; Fischer, Emily; O'Neil, Kristen; Bileto, Stephanie
2007-01-01
The purpose of this project was to determine if a multiple-week learner-centered hand washing program could improve hand hygiene behaviors of 2nd-graders in a northern Illinois public school system. Volunteers from the Rockford Hand Washing Coalition went into 19 different classrooms for 4 consecutive weeks and taught a learner-centered program.…
The Effect of Using Computer Edutainment on Developing 2nd Primary Graders' Writing Skills
ERIC Educational Resources Information Center
Mohammed Abdel Raheem, Azza Ashraf
2011-01-01
The present study attempted to examine the effect of using computer edutainment on developing 2nd graders' writing skills. The study comprised thirty-second year primary stage enrolled in Bani Hamad primary governmental school, Minia governorate. The study adopted the quasi-experimental design. Thirty participants were randomly assigned to one…
70. VIEW OF LIFEGUARD TOWER ON SOUTHEAST SIDE OF 2ND ...
70. VIEW OF LIFEGUARD TOWER ON SOUTHEAST SIDE OF 2ND TEE (LEFT) AND NORTHWEST SIDE OF TEE (RIGHT), WITH VIEW OF PILINGS, LOOKING SOUTH-SOUTHWEST - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA
71. VIEW OF NORTHWEST SIDE OF 2ND TEE (LEFT), SHOWING ...
71. VIEW OF NORTHWEST SIDE OF 2ND TEE (LEFT), SHOWING VIEW OF PILINGS, LIFEGURD TOWER ON SOUTHEAST SIDE OF TEE (RIGHT), LOOKING EAST-NORTHEAST - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA
NASA Astrophysics Data System (ADS)
Rong, Shu-Jun; Liu, Qiu-Yu
2012-04-01
The puma model on the basis of the Lorentz and CPT violation may bring an economical interpretation to the conventional neutrinos oscillation and part of the anomalous oscillations. We study the effect of the perturbation to the puma model. In the case of the first-order perturbation which keeps the (23) interchange symmetry, the mixing matrix element Ue3 is always zero. The nonzero mixing matrix element Ue3 is obtained in the second-order perturbation that breaks the (23) interchange symmetry.
Hou Weishu; Li Hsiangnan; Mishima, Satoshi; Nagashima, Makiko
2007-03-30
We study the effect from a sequential fourth generation quark on penguin-dominated two-body nonleptonic B meson decays in the next-to-leading order perturbative QCD formalism. With an enhancement of the color-suppressed tree amplitude and possibility of a new CP phase in the electroweak penguin amplitude, we can account better for A{sub CP}(B{sup 0}{yields}K{sup +}{pi}{sup -})-A{sub CP}(B{sup +}{yields}K{sup +}{pi}{sup 0}). Taking |V{sub t{sup '}}{sub s}V{sub t{sup '}}{sub b}|{approx}0.02 with a phase just below 90 deg., which is consistent with the b{yields}sl{sup +}l{sup -} rate and the B{sub s} mixing parameter {delta}m{sub B{sub s}}, we find a downward shift in the mixing-induced CP asymmetries of B{sup 0}{yields}K{sub S}{pi}{sup 0} and {phi}K{sub S}. The predicted behavior for B{sup 0}{yields}{rho}{sup 0}K{sub S} is opposite.
NASA Astrophysics Data System (ADS)
Bobodzhanov, A. A.; Safonov, V. F.
2016-04-01
We consider an algorithm for constructing asymptotic solutions regularized in the sense of Lomov (see [1], [2]). We show that such problems can be reduced to integro-differential equations with inverse time. But in contrast to known papers devoted to this topic (see, for example, [3]), in this paper we study a fundamentally new case, which is characterized by the absence, in the differential part, of a linear operator that isolates, in the asymptotics of the solution, constituents described by boundary functions and by the fact that the integral operator has kernel with diagonal degeneration of high order. Furthermore, the spectrum of the regularization operator A(t) (see below) may contain purely imaginary eigenvalues, which causes difficulties in the application of the methods of construction of asymptotic solutions proposed in the monograph [3]. Based on an analysis of the principal term of the asymptotics, we isolate a class of inhomogeneities and initial data for which the exact solution of the original problem tends to the limit solution (as \\varepsilon\\to+0) on the entire time interval under consideration, also including a boundary-layer zone (that is, we solve the so-called initialization problem). The paper is of a theoretical nature and is designed to lead to a greater understanding of the problems in the theory of singular perturbations. There may be applications in various applied areas where models described by integro-differential equations are used (for example, in elasticity theory, the theory of electrical circuits, and so on).