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The Strut-and-Tie modeling (STM) technique represents an applicable and valuable method for structural engineers to design disturbed regions (D-regions) of reinforced concrete structures where the assumption of plane sections remaining plane after loading is inapplicable. The most important aspect to guarantee the suitable structural and economic performance of the design is finding a suitable trussanalogy model, leading to the use of a more efficient model in structural buildings. The evaluation of the antisymmetric Strut-and-Tie models (STM) with openings under different concentrated external loads has not been comprehensively investigated in the literature. So, to address this gap, the goal of this paper is to achieve the most efficient reinforcement layout design in antisymmetric reinforced concrete deep beams with openings under concentrated loading using the strut and tie model. The experimental work was conducted and included (3) antisymmetric reinforced concrete deep beams with openings that were tested under different concentrated loadings (25, 35, and 16 kips for Specimens 1, 2, and 3, respectively) using the strut and tie model. The ANSYS FEM software is used for the initial strut and tie analysis, and the RISA-3D structural analysis program is used to find the internal forces for all members under concentrated external loads in each specimen. The findings of this paper show that Specimen 1 had the highest efficiency of 1.67, while Specimen 3 had the lowest efficiency of 1.31. It can be concluded that the efficient reinforcement layout of the strut and tie model leads to the highest efficiency of the model, regardless of the value of the externally applied load. [ABSTRACT FROM AUTHOR]

We study the one-way transmission and mode conversion of elastic waves by a hybrid phononic-crystal structure that consists of two mutually perpendicular phononic-crystal waveguides connected by a resonant cavity. Based on the mode matching mechanism between the cavity and waveguides, the symmetrical waves incident on the waveguide entrance are converted into antisymmetric modes and exit the waveguide. However, for the same waves incident on the structure from the waveguide exit, no output waves are transmitted toward the waveguide entrance because the modes in the waveguides and the cavity are mismatched. On the basis of this unique property, we designed a polarization-sensitive composite structure to measure the angle between two components of incident mixed elastic waves. [ABSTRACT FROM AUTHOR]

We report a quantum Monte Carlo study, on a very simple but nevertheless very instructive model system of four hydrogen atoms, recently proposed in Gasperich et al. [J. Chem. Phys. 147, 074106 (2017)]. We find that the Jastrow correlated Antisymmetrized Geminal Power (JAGP) is able to recover most of the correlation energy even when the geometry is symmetric and the hydrogens lie on the edges of a perfect square. Under such conditions, the diradical character of the molecule ground state prevents a single determinant Ansatz to achieve an acceptable accuracy, whereas the JAGP performs very well for all geometries. Remarkably, this is obtained with a similar computational effort. Moreover, we find that the Jastrow factor is fundamental in promoting the correct resonances among several configurations in the JAGP, which cannot show up in the pure Antisymmetrized Geminal Power (AGP). We also show the extremely fast convergence of this approach in the extension of the basis set. Remarkably, only the simultaneous optimization of the Jastrow and the AGP part of our variational Ansatz is able to recover an almost perfect nodal surface, yielding therefore state of the art energies, almost converged in the complete basis set limit, when the so called diffusion Monte Carlo is applied. [ABSTRACT FROM AUTHOR]

A new truncation scheme for non-orthogonal antisymmetrized products of interacting geminals (APIG) is introduced based on antisymmetrized products of strongly orthogonal geminals (APSG). This wavefunction hierarchy of interacting geminals (IG) allows us to gradually increase the accuracy at which the ground state of a seniority-zero Hamiltonian can be estimated, ranging from APSG up to approximation-free APIG. Mathematical expressions for the lowest four orders (IG0, IG1, IG2, and IG3) are given explicitly and the computational cost to evaluate their transition density matrix is verified to scale only cubically with system size. Exemplary numerical calculations indicate that already a very early truncation level leads to results virtually identical to APIG. [ABSTRACT FROM AUTHOR]

Vibrational excitations of reactants sometimes promote reactions more effectively than the same amount of translational energy. Such mode specificity provides insights into the transition-state modulation of reactivity and might be used to control chemical reactions. We report here a state-ofthe- art full-dimensional quantum dynamical study of the hydrogen abstraction reaction H + NH3 → H2 + NH2 on an accurate ab initio based global potential energy surface. This reaction serves as an ideal candidate to study the relative efficacies of symmetric and degenerate antisymmetric stretching modes. Strong mode specificity, particularly for the NH3 stretching modes, is demonstrated. It is further shown that nearly identical efficacies of the symmetric and antisymmetric stretching modes of NH3 in promoting the reaction can be understood in terms of local-mode stretching vibrations of the reactant molecule. [ABSTRACT FROM AUTHOR]

The correspondence between the isoscalar monopole (IS0) transition strengths and |$\alpha$| inelastic cross sections, the |$B({\rm IS0})$| – |$(\alpha,\alpha')$| correspondence, is investigated for |$^{24}$| Mg(⁠|$\alpha,\alpha'$|⁠) at 130 and 386 MeV. We adopt a microscopic coupled-channel reaction framework to link structural inputs, diagonal and transition densities, for |$^{24}$| Mg obtained with antisymmetrized molecular dynamics to the (⁠|$\alpha,\alpha'$|⁠) cross sections. We aim at clarifying how the |$B({\rm IS0})$| – |$(\alpha,\alpha')$| correspondence is affected by the nuclear distortion, the in-medium modification to the nucleon–nucleon effective interaction in the scattering process, and the coupled-channel effect. It is found that these effects are significant and the explanation of the |$B({\rm IS0})$| – |$(\alpha,\alpha')$| correspondence in the plane wave limit with the long-wavelength approximation, which is often used, makes no sense. Nevertheless, the |$B({\rm IS0})$| – |$(\alpha,\alpha')$| correspondence tends to remain because of a strong constraint on the transition densities between the ground state and the |$0^+$| excited states. The correspondence is found to hold at 386 MeV with an error of about 20%–30%, while it is seriously compromised at 130 MeV, mainly by the strong nuclear distortion. It is also found that when a |$0^+$| state that has a different structure from a simple |$\alpha$| cluster state is considered, the |$B({\rm IS0})$| – |$(\alpha,\alpha')$| correspondence becomes less valid. For a quantitative discussion on the |$\alpha$| clustering in |$0^+$| excited states of nuclei, a microscopic description of both the structure and reaction parts will be necessary. [ABSTRACT FROM AUTHOR]

We present a new method for modeling electronically excited states that overcomes a key failing of linear response theory by allowing the underlying ground state ansatz to relax in the presence of an excitation. The method is variational, has a cost similar to ground state variational Monte Carlo, and admits both open and periodic boundary conditions. We present preliminary numerical results showing that, when paired with the Jastrow antisymmetric geminal power ansatz, the variation-after-response formalism delivers accuracies for valence and charge transfer single excitations on par with equation of motion coupled cluster, while surpassing coupled cluster's accuracy for excitations with significant doubly excited character. [ABSTRACT FROM AUTHOR]

Temperature-dependent sum-frequency scattering spectroscopy is used to study the properties of hexadecane and dodecane oil droplets in water. The sum-frequency scattering spectra contain vibrational bands that correspond to the symmetric and antisymmetric CH stretching vibrations of the methylene (CH2) and methyl (CH3) groups of the alkane molecules. The relative amplitudes of the vibrational bands provide information on the surface structure and the shape of the oil droplets. We study the sum-frequency scattering spectra over a temperature range of -48 to 24 C, including the freezing transitions of the water matrix and the oil droplets. Hexadecane oil droplets freeze at a higher temperature than the surrounding water, whereas dodecane oil droplets freeze at a lower temperature than the surrounding water. This allows us to independently study the freezing effect of oil and water on the surface structure of the oil droplets. In both cases, freezing leads to a change in the polarization dependencies that are valid in the case of the spherical-symmetric shapes that the oil droplets assume when both water and oil are liquid. We find that the freezing of water leads to a strong distortion of the liquid dodecane surface but has little effect on the surface of already solidified hexadecane. For completely frozen emulsions a further decrease in temperature is observed to lead to a further distortion of the surface of the solid oil particles, which might be caused by increasing hardness of the ice matrix encapsulating the particles. [ABSTRACT FROM AUTHOR]

In energy decomposition analysis of Kohn-Sham density functional theory calculations, the so-called frozen (or pre-polarization) interaction energy contains contributions from permanent electrostatics, dispersion, and Pauli repulsion. The standard classical approach to separate them suffers from several well-known limitations. We introduce an alternative scheme that employs valid antisymmetric electronic wavefunctions throughout and is based on the identification of individual fragment contributions to the initial supersystem wavefunction as determined by an energetic optimality criterion. The density deformations identified with individual fragments upon formation of the initial supersystem wavefunction are analyzed along with the distance dependence of the new and classical terms for test cases that include the neon dimer, ammonia borane, water-Na+, water-Cl-, and the naphthalene dimer. [ABSTRACT FROM AUTHOR]

This article discusses how a trade‐off between the high directionality of emissions and low threshold gain can be achieved in active eccentric microring cavities. Our findings are based on the lasing eigenvalue problem formalism, considered using the method of analytical regularisation, and an extremely fast and accurate dedicated Galerkin method, applied to a set of associated Muller boundary integral equations. This method allows us to investigate symmetric and antisymmetric modes separately, on the threshold of nonattenuation in time emission. Numerical results show that the directivities of emission of working modes in a given frequency range, together with their threshold values of gain, are controlled by the size and location of the air hole in the cavity. The high efficiency of the developed code allows us to make an elementary optimisation of the considered cavity; this code is a promising engineering tool in the design of microring lasers. [ABSTRACT FROM AUTHOR]

Jastrow correlation factors play an important role in quantum Monte Carlo calculations. Together with an orbital based antisymmetric function, they allow the construction of highly accurate correlation wave functions. In this paper, a generic expansion of the Jastrow correlation function in terms of polynomials that satisfy both the electron exchange symmetry constraint and the cusp conditions is presented. In particular, an expansion of the three-body electron-electron-nucleus contribution in terms of cuspless homogeneous symmetric polynomials is proposed. The polynomials can be expressed in fairly arbitrary scaling function allowing a generic implementation of the Jastrow factor. It is demonstrated with a few examples that the new Jastrow factor achieves 85%-90% of the total correlation energy in a variational quantum Monte Carlo calculation and more than 90% of the diffusion Monte Carlo correlation energy. [ABSTRACT FROM AUTHOR]

We extend high-momentum antisymmetrized molecular dynamics (HMAMD) by incorporating the short-range part of the unitary correlation operator method (UCOM) as the variational method of finite nuclei. In this HMAMD+UCOM calculation of light nuclei, HMAMD is mainly in charge of the tensor correlation with up to four-body correlation, while the short-range correlation is further improved by using UCOM. The binding energies of the |$^3$| H and |$^4$| He nuclei are calculated with HMAMD+UCOM using the AV8 |$'$| bare nucleon–nucleon (⁠|$NN$|⁠) interaction. The different roles of the short-range and tensor correlations from HMAMD and UCOM are analyzed in the numerical results. Compared with previous calculations based on different variational methods, this newly extended HMAMD+UCOM method can almost provide consistent results with ab initio results. [ABSTRACT FROM AUTHOR]

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We show that the lowest-energy solution of the Hartree–Fock–Bogoliubov (HFB) equation has even particle-number parity as long as the time-reversal symmetry is conserved in the HFB Hamiltonian without null eigenvalues. Based on this finding, we give a rigorous foundation for a method for solving the HFB equation to describe the ground state of odd-mass nuclei by employing a time-reversal antisymmetric constraint operator to the Hamiltonian, where one obtains directly the ground state as a self-consistent solution of the cranked-HFB-type equation. Numerical analysis is performed for the neutron-rich Mg isotopes with a reasonable choice for the operator, and it is demonstrated that the anomalous increase in the matter radius of |$^{37}$| Mg is well described when the last neutron occupies a low-angular-momentum orbital in the framework of the nuclear energy density functional method, revealing the deformed halo structure. [ABSTRACT FROM AUTHOR]

We report a new three-dimensional potential energy surface for Ar-CS2 involving the Q3 normal mode for the u3 antisymmetric stretching vibration of the CS2 molecule. The potential energies were calculated using the supermolecular method at the coupled-cluster singles and doubles level with noniterative inclusion of connected triples, using augmented correlation-consistent quadruple-zeta basis set plus midpoint bond functions. Two vibrationally averaged potentials with CS2 at both the ground (u = 0) and the first excited (u = 1)u3 vibrational states were generated from the integration of the three-dimensional potential over the Q3 coordinate. Each potential was found to have a T-shaped global minimum and two equivalent linear local minima. The radial discrete variable representation /angular finite basis representation method and the Lanczos algorithm were applied to calculate the rovibrational energy levels. The calculated band origin shift of the complex (0.0622 cm-1 ) is very close to the observed one (0.0671 cm-1). The predicted infrared spectra and spectroscopic parameters based on the two averaged potentials are in excellent agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O·O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm-1. In addition to the five minima, 11 higher-order stationary points are identified. [ABSTRACT FROM AUTHOR]

The neutral-to-ionic phase transition in the mixed-stack charge-transfer complex tetrathiafulvalenep-chloranil (TTF-CA) has been studied by pressure-dependent infrared spectroscopy up to p = 11 kbar and down to low temperatures, T = 10 K. By tracking the C=O antisymmetric stretching mode of CA molecules, we accurately determine the ionicity of TTF-CA in the pressure-temperature phase diagram. At any point, the TTF-CA crystal bears only a single ionicity; there is no coexistence region or an exotic high-pressure phase. Our findings shed new light on the role of electron-phonon interaction in the neutral-ionic transition. [ABSTRACT FROM AUTHOR]

A statistical method is derived for the calculation of thermodynamic properties of many-body systems at low temperatures. This method is based on the self-healing diffusion Monte Carlo method for complex functions [F. A. Reboredo, J. Chem. Phys. 136, 204101 (2012)] and some ideas of the correlation function Monte Carlo approach [D. M. Ceperley and B. Bernu, J. Chem. Phys. 89, 6316 (1988)]. In order to allow the evolution in imaginary time to describe the density matrix, we remove the fixed-node restriction using complex antisymmetric guiding wave functions. In the process we obtain a parallel algorithm that optimizes a small subspace of the many-body Hilbert space to provide maximum overlap with the subspace spanned by the lowest-energy eigenstates of a many-body Hamiltonian. We show in a model system that the partition function is progressively maximized within this subspace. We show that the subspace spanned by the small basis systematically converges towards the subspace spanned by the lowest energy eigenstates. Possible applications of this method for calculating the thermodynamic properties of many-body systems near the ground state are discussed. The resulting basis can also be used to accelerate the calculation of the ground or excited states with quantum Monte Carlo. [ABSTRACT FROM AUTHOR]

Performance of the antisymmetrized product of strongly orthogonal geminal (APSG) ansatz in describing ground states of molecules has been extensively explored in the recent years. Not much is known, however, about possibilities of obtaining excitation energies from methods that would rely on the APSG ansatz. In the paper we investigate the recently proposed extended random phase approximations, ERPA and ERPA2, that employ APSG reduced density matrices. We also propose a time-dependent linear response APSG method (TD-APSG). Its relation to the recently proposed phase including natural orbital theory is elucidated. The methods are applied to Li2, BH, H2O, and CH2O molecules at equilibrium geometries and in the dissociating limits. It is shown that ERPA2 and TD-APSG perform better in describing double excitations than ERPA due to inclusion of the so-called diagonal double elements. Analysis of the potential energy curves of Li2, BH, and H2O reveals that ERPA2 and TD-APSG describe correctly excitation energies of dissociating molecules if orbitals involved in breaking bonds are involved. For single excitations of molecules at equilibrium geometries the accuracy of the APSG-based methods approaches that of the time-dependent Hartree-Fock method with the increase of the system size. A possibility of improving the accuracy of the TD-APSG method for single excitations by splitting the electron-electron interaction operator into the long- and short-range terms and employing density functionals to treat the latter is presented. [ABSTRACT FROM AUTHOR]

The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert space successfully overcomes two key failings of other pairing theories, namely, a lack of inter-pair correlations and a lack of multiple resonance structures, while maintaining a polynomially scaling cost, variational energies, and size consistency. Here, we present efficient quantum Monte Carlo algorithms that evaluate and optimize the JAGP energy for a cost that scales as the fifth power of the system size. We demonstrate the JAGP's ability to describe both static and dynamic correlation by applying it to bond stretching in H2O, C2, and N2 as well as to a novel, multi-reference transition state of ethene. JAGP's accuracy in these systems outperforms even the most sophisticated single-reference methods and approaches that of exponentially scaling active space methods. [ABSTRACT FROM AUTHOR]

Based on the daily SE2 temperature tide at MLT altitudes (70–108 km altitudes) from Li et al. (2017; https://doi.org/10.1002/2016JA023435), which is picked up from TIMED/SABER observations at 45°S–45°N latitudes during a solar cycle (2002–2012), we decompose the high resolution (1 day) SE2 tide into a set of orthogonal Hough functions, which are orthogonal, and analyze the characteristics (i.e., annual, interannual, and day‐to‐day variations) of their coefficients. Our results show that the first antisymmetric and second symmetric Hough functions ((2, 3) and (2, 4)) are stronger than other Hough functions. The properties of the climatological variation are that: the (2, 3) function manifests an obvious semiannual variation that the monthly mean values are larger during equinoxes than solstices; the (2, 4) function presents two peak values are, respectively, in June and November with June maxima. Actually, the higher resolution SE2 tide was utilized to reveal the meteorological (day‐to‐day variabilities) of the Hough functions. It is worth to point out that the major two ranks ((2, 3) and (2, 4)) both dominate in high altitudes and all manifest remarkable semiannual variations and weak annual variations that they are larger during solstices than equinoxes with June solstice maxima. The further discussion reveals the contributions from the dominant two ranks of Hough functions absolute amplitudes play more significant role in the day‐to‐day variability of their Hough coefficients, than their phases. Key Points: Altitudinal distribution and temporal variation of the SE2 tide Hough functionsThe 1 day resolution Hough coefficients of SE2 tide are first extractedDay‐to‐day variability of the Hough coefficients of SE2 tide is first analyzed [ABSTRACT FROM AUTHOR]

The reflection and transmission characteristics of Lamb waves at an adhesive single lap joint of plates are examined theoretically by the hybrid finite element method. The adhesive joint is modeled by a linear spring-type interface, which is characterized by normal and tangential stiffnesses. For the incidence of the lowest-order antisymmetric (A0) Lamb mode in a low frequency range, it is shown that the reflection and transmission coefficients of the A0 mode take local maxima and minima at multiple frequencies. This behavior results from the interference of waves originating from the lowest-order antisymmetric guided wave mode in the overlap region. The peak frequencies of the transmission coefficient increase monotonically with increasing tangential stiffness, but are almost invariant with the normal stiffness of the adhesive joint. Furthermore, time-domain numerical simulation using the finite element method is carried out to discuss the theoretical results. As a result, for the A0 mode incidence, the reflection and transmission waveforms of the A0 mode from the lap joint are found to show long-oscillation tails. The spectral analysis for the obtained waveforms shows that these tails are necessary to identify the frequencies at which the reflection and transmission coefficients take local maxima and minima. [ABSTRACT FROM AUTHOR]

In many everyday situations, we need to rank individuals or single items having the possibility to observe the behavior of groups. In this paper we propose a way to get this ranking over the elements of a set X, starting from an arbitrary preference relation over the subsets of X and taking into account the information provided by this ranking over the subsets. To this purpose, we use a very common approach in the social choice framework: we single out some properties that a general solution should satisfy, and we prove that these properties characterize a unique solution. Given the generality of the approach, we believe that this paper is only a starting point for a more extended analysis. In particular, it is clear that different contexts can suggest other properties, thus identifying alternative ranking methods. [ABSTRACT FROM AUTHOR]

Abstract Hybrid square tubes wrapping fiber reinforced polymer (FRP) around metallic tubes are excellent structures for both collision energy absorption and lightweight. This paper deals with axial crushing theory of hybrid square tubes wrapped with antisymmetric angle-ply. The energy dissipation mechanism of hybrid square tubes is analyzed based on deformation of metallic square tubes. Considering the effects of stacking sequences of FRP on the crashworthiness and energy absorption, theoretical expressions of the membrane force and fully plastic bending moments per unit length of hybrid squares tube are derived. Then, the expression of mean crushing force of hybrid square tubes wrapped with antisymmetric angle-ply is established. Theoretical predictions compare well with the results of three groups of experiments and forty simulation models. The theoretical calculation presented in this paper can predict the behavior of hybrid square tubes during the conceptual design. Highlights • The energy dissipation mechanism of hybrid square tubes wrapped with antisymmetric angle-ply is analyzed. • Membrane force and bending moments are derived considering the effect of stacking sequences of FRP on energy absorption. • The mean crushing force of hybrid square tubes is obtained and validated by experiments and simulations. • The theoretical analysis provides a method to predict the behavior of hybrid square tubes during the conceptual design. [ABSTRACT FROM AUTHOR]

In this paper, we prove a Hopf type lemma for anti-symmetric functions involving fractional equations. We believe that it will become a powerful tool in applying the method of moving planes on fractional equations to obtain qualitative properties of solutions. [ABSTRACT FROM AUTHOR]

Abstract Based on first principles calculations, this study reveals that magnetism in otherwise non-magnetic materials can originate from the partial occupation of antibonding states. Since the antibonding wavefunctions are spatially antisymmetric, the spin wavefunctions should be symmteric according to the exchange antisymmetric principle of quantum mechanics. We demonstrate that this phenomenon can be observed in a graphitic carbon nitride material, g -C 4 N 3 , which can be experimentally synthesized and seen as a honeycomb structure with a vacancy. Three dangling bonds of N atoms pointing to the vacancy site interact with each other to form one bonding and two antibonding states. As the two antibonding states are near the Fermi level, and electrons should partially occupy the antibonding states in spin polarization, this leads to 1 μ B magnetic moment. [ABSTRACT FROM AUTHOR]

Direct numerical simulations are undertaken to investigate the nature of instability mechanisms induced by singular and distributed roughnesses on a blunt-capsule configuration. On the base of a capsule-like hemispherical forebody at wind-tunnel conditions (M = 5:9), we analyse the development of unsteady disturbances behind a patch of two different roughness geometries. First, spanwise periodic roughness elements are considered and cross-validation with other methods of the stability analysis is achieved. Two main unstable modes are found in the roughness wake, corresponding to the symmetric and antisymmetric modes already known for single roughness elements. Second, the case of a patch of (pseudo-)randomly distributed roughness is presented. A new type of roughness-induced cross-flow-like instability is observed for the blunt-capsule configuration. The rapid growth of primary and secondary instabilities in the cross-flow-type vortex is analysed and quantified in both the linear and nonlinear stages up to the laminar-turbulent breakdown. Spatio-temporal Fourier analysis is performed to track the onset of secondary instabilities, whereas laminar-turbulent transition is identified by the steep increase of the wall heat flux. [ABSTRACT FROM AUTHOR]

Trapped mode in three-dimensional waveguide with parallel vertical walls a distance 2d apart, when there is a circular cylinder of radius placed symmetrically between them, is investigated. The potential is the solution of the three-dimensional Laplace equation in the fluid region between the cylinder and the parallel walls and the normal derivatives of potential are zero on both the walls and the cylinder. It is shown that for a cylinder of sufficiently small radius there exists a trapped mode, having a frequency close to the cutoff frequency, which is antisymmetric about the centerline of the guide and symmetric about a line through the center of the cylinder perpendicular to the centerline. The method used in this paper is to utilize the Fourier transform of complex form to the formula derived in the Appendix which can easily transform the solution in polar coordinates into the form useful for the rectangular coordinates. Thus, it is possible to express the unknown function in the solution in rectangular coordinates in terms of the coefficients of the solution in polar coordinates. [ABSTRACT FROM AUTHOR]

We construct L∞ algebras for general “initial data” given by a vector space equipped with an antisymmetric bracket not necessarily satisfying the Jacobi identity. We prove that any such bracket can be extended to a 2-term L∞ algebra on a graded vector space of twice the dimension, with the 3-bracket being related to the Jacobiator. While these L∞ algebras always exist, they generally do not realize a nontrivial symmetry in a field theory. In order to define L∞ algebras with genuine field theory realizations, we prove the significantly more general theorem that if the Jacobiator takes values in the image of any linear map that defines an ideal there is a 3-term L∞ algebra with a generally nontrivial 4-bracket. We discuss special cases such as the commutator algebra of octonions, its contraction to the “R-flux algebra,” and the Courant algebroid. [ABSTRACT FROM AUTHOR]

Abstract In this relatively unique study, the impact of adding nanoparticles (NPs) on the fatigue properties of antisymmetric glass fiber reinforced polymer (GFRP) laminate has been investigated. Antisymmetric GFRP laminates (+45/0 2 /90 2 /0 2 /-45) were prepared and reinforced once with 0.1 wt% of single-walled carbon nanotubes (SWCNTs) and then with 0.1 wt% of Graphene nanoplatelets (GNPs). The NPs reinforced GFRP laminates are termed here GFNRP nanocomposites. Ultrasonication method was used to disperse the NPs using carefully chosen process parameters. Fatigue tests were analyzed based on S-N curves, stiffness degradation and hysteresis loops. The results showed that the use of 0.1 wt% of SWCNTs led to an increase in the fatigue strength coefficient (FSC) and the fatigue strength exponent (FSE) of GFNRP nanocomposite specimens by 51% and 24%, respectively, while the use of similar wt.% of GNPs enhanced the FSC and FSE by 33% and 25%, respectively. Consequently, fatigue life of GFNRP nanocomposites are surprisingly enhanced by about three and twelve times when GNPs and SWCNTs are used, respectively. The findings would give designers much more confidence in using antisymmetric composite laminates in specific elastic tailoring structures. [ABSTRACT FROM AUTHOR]

Abstract An analytical solution determining the fundamental frequency of a fully clamped composite anisotropic laminated plate is presented in the paper. The plate is composed of unidirectional composite plies oriented at some angle to one of the plate sides. The plies alternating over the plate thickness differ from each other by only the sign of the angle of orientation. Such a plate is characterised by the structural anisotropy with the extension-twisting and bending-shear coupling effects which are taken into account in the appropriate constitutive equations. The governing equations model the coupled in-plane and out-of-plane plate motions. The vibration problem is solved using the Galerkin method. The beam functions corresponding to the first vibration mode of a beam with clamped ends are employed as the approximating functions. The problem is reduced to a solution of cubic algebraic equation. Based on this solution, effects of the angle of reinforcement orientation and number of plies on the fundamental frequency of the plate with structural anisotropy are investigated. The results are verified using finite element method. An assessment of the anisotropy effect on the frequency value has been performed by comparison with the results obtained based on the orthotropic model of the plate. The formula providing the number of plies for a plate with structural anisotropy is derived for the prescribed fundamental frequency. [ABSTRACT FROM AUTHOR]

Highlights • We propose a modified design of the omnidirectional electromagnetic acoustic transducer (EMAT) for antisymmetric (A0) Lamb wave generation. • Numerical simulation based on FEM is performed to characterize the magnetic configurations and determine the coil parameter of the EMAT. • The double-turn coil is used instead of a single spiral coil. • The proposed EMAT can generate and receive pure single A0 mode Lamb wave signal with high signal to ratio. Abstract This work presents a modified design of electromagnetic acoustic transducer (EMAT) that generates only antisymmetric (A0) omnidirectional Lamb wave. The new magnetic configuration includes a solid cylindrical magnet and a ring-shaped magnet surrounding the outside of the solid cylindrical magnet. The diameter of the solid cylindrical magnet is slightly small than the inner diameter of the ring-shaped magnet. The double-turn coil is used instead of a single spiral coil. Numerical simulation is applied to characterize the magnets and determine the coil parameters. Experimental results on a 3 mm-thick aluminum plate show that the modified EMAT we proposed can generate and receive pure single A0 mode Lamb wave with high signal to noise ratio and can effectively meet the imaging requirements. [ABSTRACT FROM AUTHOR]

Large- N phase transitions occurring in massive 𝒩 = 2 theories can be probed by Wilson loops in large antisymmetric representations. The logarithm of the Wilson loop is effectively described by the free energy of a Fermi distribution and exhibits second-order phase transitions (discontinuities in the second derivatives) as the size of representation varies. We illustrate the general features of antisymmetric Wilson loops on a number of examples where the phase transitions are known to occur: 𝒩 = 2 SQCD with various mass arrangements and 𝒩 = 2 ∗ theory. As a byproduct, we solve planar 𝒩 = 2 SQCD with three independent mass parameters. This model has two effective mass scales and undergoes two phase transitions. In memory of Ludvig Dmitrievich Faddeev [ABSTRACT FROM AUTHOR]

We present a strong absorption model with an S -matrix in a new form of an antisymmetrized Fermi distribution for describing diffraction patterns of neutron–nucleus scattering at intermediate energies. The proposed antisymmetric S -matrix has a form close to the conventional one and allows to obtain exact analytical expressions for the damping factor that determines the elastic scattering amplitude and the total cross-sections for interaction, reactions and elastic scattering. The use of an antisymmetrized Fermi function instead of the usual Fermi function in successful strong absorption models basically does not notably affect the calculated nucleon–nucleus elastic scattering differential cross-sections in the intermediate energy region. [ABSTRACT FROM AUTHOR]

We introduce a one-dimensional PT-symmetric system, which includes the cubic self-focusing, a double-well potential in the form of an infinitely deep potential box split in the middle by a delta-functional barrier of an effective height ε, and constant linear gain and loss, γ, in each half-box. The system may be readily realized in microwave photonics. Using numerical methods, we construct PT-symmetric and antisymmetric modes, which represent, respectively, the system's ground state and first excited state, and identify their stability. Their instability mainly leads to blowup, except for the case of ε = 0, when an unstable symmetric mode transforms into a weakly oscillating breather, and an unstable antisymmetric mode relaxes into a stable symmetric one. At ε >0, the stability area is much larger for the PT-antisymmetric state than for its symmetric counterpart. The stability areas shrink with increase of the total power, P. In the linear limit, which corresponds to P&8594; 0, the stability boundary is found in an analytical form. The stability area of the antisymmetric state originally expands with the growth of γ, and then disappears at a critical value of γ. [ABSTRACT FROM AUTHOR]

Abstract In this paper we prove the existence of a nontrivial τ -antisymmetric solution for the following system { − Δ u + u = | u | 2 p − 2 u + β (x) | v | p | u | p − 2 u , in R N − Δ v + ω 2 v = | v | 2 p − 2 v + β (x) | u | p | v | p − 2 v , in R N where N ≥ 3 , 2 < 2 p < 2 ⁎ , ω > 0 is a positive constant and τ : R N → R N is a nontrivial orthogonal involution. Here β is a continuous function, invariant under τ , satisfying additional conditions, some of them related to ω. The basic tool employed here is the Concentration Compactness Principle. [ABSTRACT FROM AUTHOR]

The mathematical underpinnings of a universal atomic-pair based approach to ab initio calculations of the electronic wave functions and energies of molecules and other atomic clusters are reported in non-relativistic Born-Oppenheimer approximation. The general approach utilizes the closure of an orthonormal (Eisenschitz-London) outer product of atomic spectral eigenstates to support totally antisymmetric aggregate eigenstates in the absence of explicit term-by-term atomic-product basis antisymmetry. Meaningful definitions of atomic-pair interaction operators and of their corresponding universal matrix representatives on the atomic product basis are obtained in this way for calculations on physical and chemical aggregates. Symmetric-group-based permutation-symmetry methods for partitioning of aggregate Hamlitonian matrices, performed to date by unitary transformations to remove unphysical “non-Pauli” states after aggregate Hamiltonian matrix construction, are supplemented here with a new two-step procedure. The new approach, which combines explicit antisymmetrization of atomic pair matrices with unitary transformation of aggregate Hamiltonian matrices, is described here in complete mathematical detail. Conditions are established from the new development under which enforcement of pairwise-atomic antisymmetry alone can be sufficient for calculations of electronic energies, providing an efficient approach for practical applications, as well as long-absent theoretical support for related semi-empirical and ad hoc methods widely employed in computational molecular physics and quantum chemistry. An exact expression is obtained for total electronic energies from the solution of the Schrödinger equation in the universal form of sums over pairwise-atomic interaction energies uniquely defined within a molecule in the absence of subjective additional conditions. Wigner rotation matrices are employed to orient pairs of interacting atoms within an aggregate in the implementation of the approach, requiring calculations of the universal pair interaction matrices as functions of radial separations only. Such information can be obtained once and for all from molecular diatomic calculations and retained for subsequent use, avoiding repeated evaluations of the electronic integrals commonly required in conventional variational determinations of accurate potential energy surfaces. Diagonalizations of large Hamiltonian matrices are avoided in favor of optical potential, Krylov-Lanczos, and previously described Stieltjes-Techebycheff methods in determination of aggregate Schrödinger eigenspectra. [ABSTRACT FROM AUTHOR]

The linear properties of both even and odd double tearing modes (DTMs) in the presence of plasma shear flow are studied based on a reduced resistive MHD model in slab geometry. It is found that for the anti-symmetric shear flow, the linear growth rates γ (k y) of the even (odd) eigenmode of DTMs decrease (increase) with increasing the strength of shear flow. Indeed, in the small wavenumber k y regime, γ (k y) of the even eigenmode is larger than that of the odd eigenmode, while γ (k y) of two kinds of eigen states coalesce with each other (the same growth rate and opposite frequencies) when the wavenumber k y exceeds a critical value k y C . It is demonstrated that k y C decreases with decreasing η for a fixed separation between two resonant surfaces x s , while decreasing x s increases the critical value of k y C for a fixed shear velocity. In the nonlinear regime for a low value of resistivity, it is observed that by increasing the strength of anti-symmetric shear flow, in the early phase of the abrupt regime a monster plasmoid and subsidary small plasmoids are generated, and later they are ejected from the DTM current sheet and merged with the main DTM islands. [ABSTRACT FROM AUTHOR]

Moiré interferometry is an effective full-field deformation measurement technique and has been utilized for mechanical behavior analysis of materials and structures. For isotropic materials, Moiré patterns can be obtained by performing standard tests, such as, tensile and bending tests, to calculate the displacement and strain. Then, the mechanical properties can be characterized. However, standard tests are not sufficient to characterize the mechanical parameters of anisotropic materials due to the complexity of their material properties. Thus, in this work, Moiré interferometry was combined with the Virtual Fields Method to obtain the four in-plane elastic constants (Q11, Q22, Q12, and Q66) of orthotropic materials in the form of a diametrically compressed disk. Firstly, according to finite element method simulation results, optimized parameters can be achieved when the principal direction of the material does not coincide with the loading direction, making the loading configuration antisymmetric. Therefore, Moiré interferometry experiment was simulated to demonstrate the feasibility of measurement in the antisymmetric configuration. Finally, the Q11, Q22, Q12 and Q66 values of a unidirectional carbon fiber composite were measured in a real Moiré interferometry experiment using the proposed method, yielding results that agreed closely with those obtained using the strain gauges. [ABSTRACT FROM AUTHOR]

Results of quantum mechanical computations of the antisymmetric part of the indirect spin-spin coupling tensor, , performed using the coupled-cluster method, the second-order polarisation propagator approximation, and the density functional theory for 25 molecules and nearly 100 spin-spin couplings are reported. These results are used for an estimation of the magnitude of the recently proposed liquid-state nuclear magnetic resonance chirality-sensitive effect, which allows to determine the molecular chirality directly, i.e. without the need for the application of any chiral agent. The following were found: (i) the antisymmetry J⋆ is usually larger for the coupling between spins separated by two chemical bonds in comparison with the coupling through one bond, (ii) promising samples are those which contain fluorine, and (iii) the antisymmetry of the spin-spin coupling tensor is of the order of a few hertz for commercially available chemical compounds. Therefore, the relevant property of the experiment, the pseudoscalar Jc, for them is of the order of 1 nHz m/V. [ABSTRACT FROM AUTHOR]

Free vibration of antisymmetric angle-ply laminated plates with variable thickness is studied. Higher-order shear deformation plate theory (HSDT) is introduced in the present method to remove the shear correction factors and improve the accuracy of transverse shear stresses. The thickness variations are assumed to be linear, exponential, and sinusoidal. The coupled differential equations are obtained in terms of displacement and rotational functions and approximated using cubic and quantic spline. A generalized eigenvalue problem is obtained and solved numerically by employing the eigensolution techniques with eigenvectors as spline coefficients to obtain the required frequencies. The results of numerical calculations are presented for laminated plates with simply supported boundary conditions. Comparisons of the current solutions and those reported in literature are provided to verify the accuracy of the proposed method. The effects of aspect ratio, number of layers, ply-angles, side-to-thickness ratio, and materials on the free vibration of cylindrical plates are discussed in detail. [ABSTRACT FROM AUTHOR]

Based on first order shear deformation theory, free vibrational behaviour of antisymmetric angle-ply composite annular plate is investigated. The thickness variations are assumed to be linear, exponential and sinusoidal along the radial direction. The equilibrium equations are obtained from which the coupled differential equations are derived in terms of displacement and rotation functions. These functions are approximated using splines to obtain the system of algebraic equations in terms of spline coefficients where the equation becomes a generalized eigenvalue problem by combining the boundary conditions. This problem is solved for finding eigenfrequencies and corresponding eigenvectors. This study is conducted for clamped-clamped and clamped-free boundary conditions. Detailed parametric investigation is carried out to determine the influences of radii ratio, number of layers, ply orientations and materials on the frequencies of plates. The primary results of this study are compared with those available in the literatures. [ABSTRACT FROM AUTHOR]

The dispersion properties of surface dust ion-acoustic waves in a self-gravitating magnetized dusty plasma layer with the (r, q) distribution are investigated. The result shows that the wave frequency of the symmetric mode in the plasma layer decreases with an increase in the wave number. It is also shown that the wave frequency of the symmetric mode decreases with an increase in the spectral index r. However, the wave frequency of the anti-symmetric mode increases with an increase in the wave number. It is also found that the anti-symmetric mode wave frequency increases with an increase in the spectral index r. In addition, it is found that the influence of the self-gravitation on the symmetric mode wave frequency decreases with increasing scaled Jeans frequency. Moreover, it is found that the wave frequency of the symmetric mode increases with an increase in the dust charge; however, the anti-symmetric mode shows opposite behavior. [ABSTRACT FROM AUTHOR]

In our previous report, we introduced a new version of Fermion coupled coherent states method (FCCS) which was especially suited for simulating the first symmetric spatial electronic state of two‐electron systems. In this manuscript, we report a complementary version for FCCS method to simulate both of the first symmetric and antisymmetric spatial electronic states of two‐electron systems. Moreover, the Gram–Schmidt orthogonalization process is employed to reach the excited states of the system. We apply this FCCS method and the original coupled coherent state method to simulate the energy of different electronic states of H 2 and H 2 +, respectively. The results for the energy of computed electronic states of H 2 and H 2 + show a pretty good consistency with the exact values. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Using an exact expression for the average velocity of inertialess motion of pulsating ratchets, a simple proof is given for the recently discovered hidden space-time symmetry of Cubero-Renzoni (D. Cubero, F. Renzoni, 2016). The conditions are revealed for the absence of the ratchet effect in systems with potential energies described by products of periodic functions of coordinate and time possessing the symmetry of the main types. In particular, it is shown that the ratchet effect is absent for the time dependence of the universal symmetry type (which combines three standard symmetries), and this restriction is removed when inertia is taken into account, unless the coordinate dependence of the potential energy is related to symmetric or antisymmetric functions. [ABSTRACT FROM AUTHOR]

In this paper we will apply the Faddeev-Jackiw quantization methodology to the massive open strings in the D-brane background with a non-vanishing constant B-field.We shall work in the discrete version, and the reduced phase space is obtained directly by solving the mixed boundary conditions. The non-commutativity is extended to the noncommutativity of pace coordinates and momentum coordinates along the D-brane is reproduced in easy way.We feel that this method of obtaining the noncommutativity in string theory in the massive case is more elegant than previous approaches discussed in the literature. [ABSTRACT FROM AUTHOR]

In this article the electronic structure and de Haas-van Alphen effect of LaNiC2 have been calculated by using the first-principle calculations. The antisymmetric spin-orbit coupling effect causes splitting estimated to be 62.9 and 27.5 meV in the two bands crossing the Fermi level. Regular translations between spin-up and spin-down states have been observed and calculated in discrete ranges of energy. Spin-orbit coupled Fermi surfaces are derived and the related de Hass-van Alphen effects have been simulated from the ELK-flapw calculations. The unusual disconnections in low-frequency area have been discussed in details. The Fermi surface topology of spin-up (l + 1/2) is very different from that of spin-down (l − 1/2) which is also evident by the proportions of electron-like bands. Finally the relationship between simulation results and Fermi surface details has been discussed. [ABSTRACT FROM AUTHOR]