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Molecules under strong or ultra-strong light–matter coupling present an intriguing route to modify chemical structure, properties, and reactivity. A rigorous theoretical treatment of such systems requires handling matter and photon degrees of freedom on an equal quantum mechanical footing. In the regime of molecular electronic strong or ultra-strong coupling to one or a few molecules, it is desirable to treat the molecular electronic degrees of freedom using the tools of ab initio quantum chemistry, yielding an approach referred to as ab initio cavity quantum electrodynamics (ai-QED), where the photon degrees of freedom are treated at the level of cavity QED. We analyze two complementary approaches to ai-QED: (1) a parameterized ai-QED, a two-step approach where the matter degrees of freedom are computed using existing electronic structure theories, enabling the construction of rigorous ai-QED Hamiltonians in a basis of many-electron eigenstates, and (2) self-consistent ai-QED, a one-step approach where electronic structure methods are generalized to include coupling between electronic and photon degrees of freedom. Although these approaches are equivalent in their exact limits, we identify a disparity between the projection of the two-body dipole self-energy operator that appears in the parameterized approach and its exact counterpart in the self-consistent approach. We provide a theoretical argument that this disparity resolves only under the limit of a complete orbital basis and a complete many-electron basis for the projection. We present numerical results highlighting this disparity and its resolution in a particularly simple molecular system of helium hydride cation, where it is possible to approach these two complete basis limits simultaneously. In this same helium hydride system, we examine and compare the practical issue of the computational cost required to converge each approach toward the complete orbital and many-electron bases limit. Finally, we assess the aspect of photonic convergence for polar and charged species, finding comparable behavior between parameterized and self-consistent approaches. [ABSTRACT FROM AUTHOR]

Recent quantum algorithms pertaining to electronic structure theory primarily focus on the threshold-based dynamic construction of ansatz by selectively including important many-body operators. These methods can be made systematically more accurate by tuning the threshold to include a greater number of operators into the ansatz. However, such improvements come at the cost of rapid proliferation of the circuit depth, especially for highly correlated molecular systems. In this work, we address this issue by the development of a novel theoretical framework that relies on the segregation of an ansatz into a dynamically selected core "principal" component, which is, by construction, adiabatically decoupled from the remaining operators. This enables us to perform computations involving the principal component using extremely shallow-depth circuits, whereas the effect of the remaining "auxiliary" component is folded into the energy function via a cost-efficient non-iterative correction, ensuring the requisite accuracy. We propose a formalism that analytically predicts the auxiliary parameters from the principal ones, followed by a suite of non-iterative auxiliary subspace correction techniques with different levels of sophistication. The auxiliary subspace corrections incur no additional quantum resources yet complement an inadequately expressive core of the ansatz to recover a significant amount of electronic correlations. We have numerically validated the resource efficiency and accuracy of our formalism with a number of strongly correlated molecular systems. [ABSTRACT FROM AUTHOR]

The electric dipole polarizabilities and the tune-out wavelengths for the n3S1 (n = 2, 3) states of Be2+ are determined through the application of the relativistic full-configuration-interaction approach. Our calculations directly integrate the mass shift operator into the Dirac–Coulomb–Breit Hamiltonian and further assess the quantum electrodynamics (QED) correction to the dynamic dipole polarizabilities using perturbation theory. The results reveal that the static electric dipole polarizability of the 23S1 and 33S1 states, as well as the 93 nm tune-out wavelength of the 23S1 state and the 238 nm tune-out wavelength of the 33S1 state, exhibits a high sensitivity to QED correction, which exceeds 80 ppm, providing a sensitive test for atomic structure theory. [ABSTRACT FROM AUTHOR]

The electric dipole polarizabilities and the tune-out wavelengths for the n3S1 (n = 2, 3) states of Be2+ are determined through the application of the relativistic full-configuration-interaction approach. Our calculations directly integrate the mass shift operator into the Dirac–Coulomb–Breit Hamiltonian and further assess the quantum electrodynamics (QED) correction to the dynamic dipole polarizabilities using perturbation theory. The results reveal that the static electric dipole polarizability of the 23S1 and 33S1 states, as well as the 93 nm tune-out wavelength of the 23S1 state and the 238 nm tune-out wavelength of the 33S1 state, exhibits a high sensitivity to QED correction, which exceeds 80 ppm, providing a sensitive test for atomic structure theory. [ABSTRACT FROM AUTHOR]

We employ polymer integral equation theory to study a simplified model of semiflexible polymerized ionic liquids (PolyILs) that interact via hard core repulsions and short range screened Coulomb interactions. The multi-scale structure in real and Fourier space of PolyILs (ions chosen to mimic Li, Na, K, Br, PF6, and TFSI) are determined as a function of melt density, Coulomb interaction strength, and ion size. Comparisons with a homopolymer melt, a neutral polymer–solvent-like athermal mixture, and an atomic ionic liquid are carried out to elucidate the distinct manner that ions mediate changes of polymer packing, the role of excluded volume effects, and the influence of chain connectivity, respectively. The effect of Coulomb strength depends in a rich manner on ion size and density, reflecting the interplay of steric packing, ion adsorption, and charge layering. Ion-mediated bridging of monomers is found, which intensifies for larger ions. Intermediate range charge layering correlations are characterized by a many-body screening length that grows with PolyIL density, cooling, and Coulomb strength, in disagreement with Debye–Hückel theory, but in accord with experiments. Qualitative differences in the collective structure, including an ion-size-dependent bifurcation of the polymer structure factor peak and pair correlation function, are predicted. The monomer cage order parameter increases significantly, but its collective ion counterpart decreases, as ions become smaller. Such behaviors allow one to categorize PolyILs into two broad classes of small and large ions. Dynamical implications of the predicted structural results are qualitatively discussed. [ABSTRACT FROM AUTHOR]

Simulations of photochemical reaction dynamics have been a challenge to the theoretical chemistry community for some time. In an effort to determine the predictive character of current approaches, we predict the results of an upcoming ultrafast diffraction experiment on the photodynamics of cyclobutanone after excitation to the lowest lying Rydberg state (S2). A picosecond of nonadiabatic dynamics is described with ab initio multiple spawning. We use both time dependent density functional theory (TDDFT) and equation-of-motion coupled cluster singles and doubles (EOM-CCSD) theory for the underlying electronic structure theory. We find that the lifetime of the S2 state is more than a picosecond (with both TDDFT and EOM-CCSD). The predicted ultrafast electron diffraction spectrum exhibits numerous structural features, but weak time dependence over the course of the simulations. [ABSTRACT FROM AUTHOR]

The machine learning (ML) method emerges as an efficient and precise surrogate model for high-level electronic structure theory. Its application has been limited to closed chemical systems without considering external potentials from the surrounding environment. To address this limitation and incorporate the influence of external potentials, polarization effects, and long-range interactions between a chemical system and its environment, the first two terms of the Taylor expansion of an electrostatic operator have been used as extra input to the existing ML model to represent the electrostatic environments. However, high-order electrostatic interaction is often essential to account for external potentials from the environment. The existing models based only on invariant features cannot capture significant distribution patterns of the external potentials. Here, we propose a novel ML model that includes high-order terms of the Taylor expansion of an electrostatic operator and uses an equivariant model, which can generate a high-order tensor covariant with rotations as a base model. Therefore, we can use the multipole-expansion equation to derive a useful representation by accounting for polarization and intermolecular interaction. Moreover, to deal with long-range interactions, we follow the same strategy adopted to derive long-range interactions between a target system and its environment media. Our model achieves higher prediction accuracy and transferability among various environment media with these modifications. [ABSTRACT FROM AUTHOR]

An IR–vacuum ultraviolet (VUV) ion-dip spectroscopy method is utilized to examine the IR spectrum of acetaldehyde oxide (CH3CHOO) in the overtone CH stretch (2νCH) spectral region. IR activation creates a depletion of the ground state population that reduces the VUV photoionization signal on the parent mass channel. IR activation of the more stable and populated syn-CH3CHOO conformer results in rapid unimolecular decay to OH + vinoxy products and makes the most significant contribution to the observed spectrum. The resultant IR–VUV ion-dip spectrum of CH3CHOO is similar to that obtained previously for syn-CH3CHOO using IR action spectroscopy with UV laser-induced fluorescence detection of OH products. The prominent IR features at 5984 and 6081 cm−1 are also observed using UV + VUV photoionization of OH products. Complementary theoretical calculations utilizing a general implementation of second-order vibrational perturbation theory provide new insights on the vibrational transitions that give rise to the experimental spectrum in the overtone CH stretch region. The introduction of physically motivated small shifts of the harmonic frequencies yields remarkably improved agreement between experiment and theory in the overtone CH stretch region. The prominent features are assigned as highly mixed states with contributions from two quanta of CH stretch and/or a combination of CH stretch with an overtone in mode 4. The generality of this approach is demonstrated by applying it to three different levels of electronic structure theory/basis sets, all of which provide spectra that are virtually indistinguishable despite showing large deviations prior to introducing the shifts to the harmonic frequencies. [ABSTRACT FROM AUTHOR]

HORTON is a free and open-source electronic-structure package written primarily in Python 3 with some underlying C++ components. While HORTON's development has been mainly directed by the research interests of its leading contributing groups, it is designed to be easily modified, extended, and used by other developers of quantum chemistry methods or post-processing techniques. Most importantly, HORTON adheres to modern principles of software development, including modularity, readability, flexibility, comprehensive documentation, automatic testing, version control, and quality-assurance protocols. This article explains how the principles and structure of HORTON have evolved since we started developing it more than a decade ago. We review the features and functionality of the latest HORTON release (version 2.3) and discuss how HORTON is evolving to support electronic structure theory research for the next decade. [ABSTRACT FROM AUTHOR]

Rare-earth doped materials are of immense interest for their potential applications in linear and nonlinear photonics. There is also intense interest in sub-nanometer gold clusters due to their enhanced stability and unique optical, magnetic, and catalytic properties. To leverage their emergent properties, here we report a systematic study of the geometries, stability, electronic, magnetic, and linear and nonlinear optical properties of Au5RE (RE = Sc, Y, La–Lu) clusters using density-functional theory. Several low-energy isomers consisting of planar or non-planar configurations are identified. For most doped clusters, the non-planar configuration is energetically favored. In the case of La-, Pm-, Gd-, and Ho-doped clusters, a competition between planar and non-planar isomers is predicted. A distinct preference for the planar configuration is predicted for Au5Eu, Au5Sm, Au5Tb, Au5Tm, and Au5Yb. The distinction between the planar and non-planar configurations is highlighted by the calculated highest frequencies, with the stretching mode of the non-planar configuration predicted to be stiffer than the planar configuration. The bonding analysis reveals the dominance of the RE-d orbitals in the formation of frontier molecular orbitals, which, in turn, facilitates retaining the magnetic characteristics governed by RE-f orbitals, preventing spin-quenching of rare earths in the doped clusters. In addition, the doped clusters exhibit small energy gaps between frontier orbitals, large dipole moments, and enhanced hyperpolarizability compared to the host cluster. [ABSTRACT FROM AUTHOR]

Electronic structure theory, i.e., quantum chemistry, is the fundamental building block for many problems in computational chemistry. We present a new distributed computing framework (BigChem), which allows for an efficient solution of many quantum chemistry problems in parallel. BigChem is designed to be easily composable and leverages industry-standard middleware (e.g., Celery, RabbitMQ, and Redis) for distributed approaches to large scale problems. BigChem can harness any collection of worker nodes, including ones on cloud providers (such as AWS or Azure), local clusters, or supercomputer centers (and any mixture of these). BigChem builds upon MolSSI packages, such as QCEngine to standardize the operation of numerous computational chemistry programs, demonstrated here with Psi4, xtb, geomeTRIC, and TeraChem. BigChem delivers full utilization of compute resources at scale, offers a programable canvas for designing sophisticated quantum chemistry workflows, and is fault tolerant to node failures and network disruptions. We demonstrate linear scalability of BigChem running computational chemistry workloads on up to 125 GPUs. Finally, we present ChemCloud, a web API to BigChem and successor to TeraChem Cloud. ChemCloud delivers scalable and secure access to BigChem over the Internet. [ABSTRACT FROM AUTHOR]

Modern electronic structure theory is built around the Born–Oppenheimer approximation and the construction of an electronic Hamiltonian H ̂ e l (X) that depends on the nuclear position X (and not the nuclear momentum P). In this article, using the well-known theory of electron translation (Γ′) and rotational (Γ″) factors to couple electronic transitions to nuclear motion, we construct a practical phase-space electronic Hamiltonian that depends on both nuclear position and momentum, H ̂ P S (X , P). While classical Born–Oppenheimer dynamics that run along the eigensurfaces of the operator H ̂ e l (X) can recover many nuclear properties correctly, we present some evidence that motion along the eigensurfaces of H ̂ P S (X , P) can better capture both nuclear and electronic properties (including the elusive electronic momentum studied by Nafie). Moreover, only the latter (as opposed to the former) conserves the total linear and angular momentum in general. [ABSTRACT FROM AUTHOR]

Polaritonic states, which are formed by resonances between a molecular excitation and the photonic mode of a cavity, have a number of useful properties that offer new routes to control molecular photochemistry using electric fields. To provide a theoretical description of how polaritonic states affect the real-time electron dynamics in molecules, a new method is described where the effects of strong light–molecule coupling are implemented using real-time electronic structure theory. The coupling between the molecular electronic states and the cavity is described by the Pauli–Fierz Hamiltonian, and transitions between polaritonic states are induced via an external time-dependent electric field using time-dependent configuration interaction (TDCI) theory, producing quantum electrodynamics TDCI (QED-TDCI). This method is used to study laser-induced ultrafast charge transfer and dipole-switching dynamics of the LiCN molecule inside a cavity. The increase in cavity coupling strength is found to have a significant impact on the energies and transition dipole moments of the molecule–cavity system. The convergence of the polaritonic state energies as a function of the number of included electronic and photonic basis states is discussed. [ABSTRACT FROM AUTHOR]

It is usually asserted that physical Hamiltonians for fermions must contain an even number of fermion operators. This is indeed true in electronic structure theory. However, when the Jordan–Wigner (JW) transformation is used to map physical spin Hamiltonians to Hamiltonians of spinless fermions, terms that contain an odd number of fermion operators may appear. The resulting fermionic Hamiltonian thus does not have number parity symmetry and requires wave functions that do not have this symmetry either. In this work, we discuss the extension of standard Hartree–Fock–Bogoliubov (HFB) theory to the number-parity-nonconserving case. These ideas had appeared in the literature before but, perhaps for lack of practical applications, had, to the best of our knowledge, never been employed. We here present a useful application for this more general HFB theory based on coherent states of the SO(2M + 1) Lie group, where M is the number of orbitals. We also show how using these unusual mean-field states can provide significant improvements when studying the JW transformation of chemically relevant spin Hamiltonians. [ABSTRACT FROM AUTHOR]

Because of an acquired obsession to understand as much as possible in a limited but important area of science and because of optimism, luck, and help from others, my life in science turned out to be much better than I or others could have expected or planned. This is the story of how that happened, and also the story of the groundstate density functional theory of electronic structure, told from a personal perspective. [ABSTRACT FROM AUTHOR]

Since the development of generalized gradient approximations in the 1990s, approximations based on density functional theory have dominated electronic structure theory calculations. Modern approximations can yield energy differences that are precise enough to be predictive in many instances, as validated by large- and small-scale benchmarking efforts. However, assessing the quality of densities has been the subject of far less attention, in part because reliable error measures are difficult to define. To this end, this work introduces the mean-field error, which directly assesses the quality of densities from approximations. The mean-field error is contextualized within existing frameworks of density functional error analysis and understanding and shown to be part of the density-driven error. It is demonstrated in several illustrative examples. Its potential use in future benchmarking protocols is discussed, and some conclusions are drawn. [ABSTRACT FROM AUTHOR]

Vibrational heat-bath configuration interaction (VHCI)—a selected configuration interaction technique for vibrational structure theory—has recently been developed in two independent works [J. H. Fetherolf and T. C. Berkelbach, J. Chem. Phys. 154, 074104 (2021); A. U. Bhatty and K. R. Brorsen, Mol. Phys. 119, e1936250 (2021)], where it was shown to provide accuracy on par with the most accurate vibrational structure methods with a low computational cost. Here, we eliminate the memory bottleneck of the second-order perturbation theory correction using the same (semi)stochastic approach developed previously for electronic structure theory. This allows us to treat, in an unbiased manner, much larger perturbative spaces, which are necessary for high accuracy in large systems. Stochastic errors are easily controlled to be less than 1 cm−1. We also report two other developments: (i) we propose a new heat-bath criterion and an associated exact implicit sorting algorithm for potential energy surfaces expressible as a sum of products of one-dimensional potentials; (ii) we formulate VHCI to use a vibrational self-consistent field (VSCF) reference, as opposed to the harmonic oscillator reference configuration used in previous reports. Our tests are done with quartic and sextic force fields, for which we find that with VSCF, the minor improvements to accuracy are outweighed by the higher computational cost associated the matrix element evaluations. We expect VSCF-based VHCI to be important for more general potential representations, for which the harmonic oscillator basis function integrals are no longer analytic. [ABSTRACT FROM AUTHOR]

The many-body expansion lies at the heart of numerous fragment-based methods that are intended to sidestep the nonlinear scaling of ab initio quantum chemistry, making electronic structure calculations feasible in large systems. In principle, inclusion of higher-order n-body terms ought to improve the accuracy in a controllable way, but unfavorable combinatorics often defeats this in practice and applications with n ≥ 4 are rare. Here, we outline an algorithm to overcome this combinatorial bottleneck, based on a bottom-up approach to energy-based screening. This is implemented within a new open-source software application ("Fragme∩t"), which is integrated with a lightweight semi-empirical method that is used to cull subsystems, attenuating the combinatorial growth of higher-order terms in the graph that is used to manage the calculations. This facilitates applications of unprecedented size, and we report four-body calculations in ( H 2 O) 64 clusters that afford relative energies within 0.1 kcal/mol/monomer of the supersystem result using less than 10% of the unique subsystems. We also report n-body calculations in ( H 2 O) 20 clusters up to n = 8, at which point the expansion terminates naturally due to screening. These are the largest n-body calculations reported to date using ab initio electronic structure theory, and they confirm that high-order n-body terms are mostly artifacts of basis-set superposition error. [ABSTRACT FROM AUTHOR]

Concrete is the most widely used construction material for strategic structures which are subjected to high rate of loading (impact and blast loading). Hence, the study of the concrete material becomes essential day by day for the structural engineers for the analysis and design of the concrete structures for safety and security purposes. This paper focuses on investigating the dynamic compressive response of the standard concrete (M35) and high-strength concrete (M60) under impact loading by using the newly developed split Hopkinson pressure bar setup (SHPB) apparatus. First, the calibration of SHPB performed at a 4.90 ms − 1 impact velocity generates almost similar incident and transmission trapezoidal profile waves with minor reflection showing accuracy. Second, the dynamic compression tests were performed on the standard concrete (SC) and high-strength concrete (HSC) specimens of 29.5 mm in diameter and ∼ 3 0 mm in length with an aspect ratio of about 1(L / D ≈ 1) and a comparative study of strain rate effect and quasi-static compressive strength on the material properties has been investigated. The dynamic compression behavior of SC and HSC thus studied under varying strain rates has been presented in terms of the compressive strength, dynamic increase factor, stress–strain relationship, material failure, and fragmentation. Compressive strength increments of 114% and 41% were observed in SC and HSC as the loading condition changed from quasi-static to dynamic. In addition, the HSC described the ∼ 2 3 % and ∼ 1 8 % higher compressive strength corresponding to 290 s − 1 and 131 s − 1 strain rate as compared to SC describing that the HSC is more sensitive to the strain rate. The dynamic mechanical properties increased with an increase in the strain rate, and the DIFs were found to vary in the range of 1.42–2.14 and 1.07–1.41 for SC and HSC, respectively. The critical strain and ultimate strain were also found to be sensitive to strain rate and increased with increase in strain rate for both grades of concrete. Moreover, strain rates exert a noteworthy influence on fragmentation, leading to an increase in the percentage weight of fine fragments and a decrease in the percentage weight of large fragments as the strain rate increases. Additionally, there is an overall increase in the quantity of fragments for both SC and HSC specimens under these conditions. The flaky, elongated, angular, and irregular shape fragments were observed but their quantity and size varied significantly with strain rate. [ABSTRACT FROM AUTHOR]

We consider wavefunctions built from antisymmetrized products of two‐electron wavefunctions (geminals), which is arguably the simplest extension of the antisymmetrized product of one‐electron wavefunctions (orbitals) (i.e., a Slater determinant). Extensive use of geminals in wavefunctions has been limited by their high cost stemming from the many combinations of the two‐electron basis functions (orbital pairs) used to build the geminals. When evaluating the overlap of the APG wavefunction with an orthogonal Slater determinant, this cost can be interpreted as the cost of evaluating the permanent, resulting from the symmetry with respect to the interchange of orbital pairs, and the cost of assigning the occupied orbitals to the orbital pairs of the wavefunction. Focusing on the latter, we present a graphical interpretation of the Slater determinant and utilize the maximum weighted matching algorithm to estimate the combination of orbital pairs with the largest contribution to the overlap. Then, the cost due to partitioning the occupied orbitals in the overlap is reduced from 풪((N−1)!!) to 풪(N3logN). Computational results show that many of these combinations are not necessary to obtain an accurate solution to the wavefunction. Because the APG wavefunction is the most general of the geminal wavefunctions, this approach can be applied to any of the simpler geminal wavefunction ansätze. In fact, this approach may even be extended to generalized quasiparticle wavefunctions, opening the door to tractable wavefunctions built using components of arbitrary numbers of electrons, not just two electrons. [ABSTRACT FROM AUTHOR]

Public sector creativity—public servants coming up with novel and useful ideas—is the origin of solutions and innovations central to public sector organizations' ability to optimally serve society's interests. Despite its relevance and argued limitations, an adequate scale and framework to assess public servants' creativity remained absent. Using three quantitative (n = 2434/n = 1157/n = 621) and two qualitative datasets, this state‐of‐the‐art preregistered study provides a novel, valid, reliable, comprehensive but succinct multidimensional measurement tool allowing detailed assessment of states and changes of public servants' creativity by academics and practitioners. To aid academics and practitioners' understanding of the scale and public sector creativity, it also provides a supplementary theoretical framework in line with the data structure of the scale that compresses and structures extant theory on creativity while emphasizing what is indicated as important in the public sector. The findings shed light on the nature of public sector creativity as an aggregate and multidimensional construct. [ABSTRACT FROM AUTHOR]

This work investigates the static flexural behavior of new hybrid Sandwich Plates (SP) with Functionally Graded (FG) cores and curvilinear fiber-reinforced Variable Stiffness (VS) skins. For simplicity and computational efficiency, the existing refined zig-zag theory formulation for curvilinear fiber-reinforced composites with three-node finite element (RZT3C) is enhanced to incorporate the thickness-wise material variation of the FG core. Benchmark problems of FG-SP under various boundary conditions are solved, with results compared against 3D Ansys and reference solutions. Contrary to costlier methods, the presented model accurately captures the complex flexural mechanics, paving the way for designing advanced structures. [ABSTRACT FROM AUTHOR]

Society and policy demand greater sustainability of food systems, driving practitioners to improve the transparency of supply chain networks through digital innovation. Uncertainties regarding the structuring of relationships with primary and secondary stakeholders for sharing intangible data and information diminishes the potential for exploitation of digital transparency. While businesses are accustomed to organizing efficient flows of tangible goods, management research integrating digital transparency considerations to investigate and conceptualize structural changes in agri-food supply chain networks (AFSCNs) is scarce. This gap motivates the following four questions of this study: (1) Who are the primary and secondary stakeholders in the AFSCNs of the digital era? (2) What are their transparency interests? (3) How do AFSCN structures change with the emergence of digital innovations that can facilitate sustainability transition through greater transparency? (4) How to conceptualize those structural changes to AFSCNs? The netchain approach and respective transparency concept are integrated with classical stakeholder theory. Data was collected via a series of 21 semi-structured pilot interviews with technology providers in the EU agri-food sector and analyzed using structured content analysis. Results paint a complex picture of contemporary primary and secondary stakeholders of AFSCNs and their interests. Primary stakeholder interests lead to coopetition in vertical and horizontal relationships of the netchain and low transparency efforts by intermediaries. Both hamper the dissemination of digital innovations and the exploitation of their potential to improve AFSCN sustainability. Among secondary stakeholders, policymakers and governments, NGOs, and technology providers excel in being drivers of digital transparency for sustainability, with social media as a strong direct communication tool to reach netchain stakeholders, consumers, and research institutes/universities as collaborators and customers. The emergence of "information AFSCN" and "digital AFSCN" increases the complexity of the whole supply chain network through intermediation, reconfiguration, and emergence modes of change to underlying structures. Agri-food business managers, scientists, and policymakers should innovate in private and public governance to facilitate collaborative advantage and sustainability in a combination aligned with innovative digital transparency solutions. [ABSTRACT FROM AUTHOR]

The innovative thermal management system named Two-Phase Mechanically Pumped Loop (2PMPL) has been investigated to design probes for Venus exploration. This study aims integrating the 2PMPL evaporator inside the probe shell, using the Laser Powder Bed Fusion technique, to reduce the thermal system size and to increase the payload. In this paper, four evaporator designs have been developed and compared to the latest available reference solution. The overall assessment of those designs has been performed by comparing the results of basic Computational Fluid Dynamics analysis, structural behavior, mass and Three-Phase Contact Line (TPCL) length, highlighting specific strengths of each solution. [ABSTRACT FROM AUTHOR]

Sandwich structures have been a subject of intense scrutiny and utilization in engineering applications. However, there has been a limited understanding of the mechanical behaviors of novel sandwich structures composed of auxetic metamaterials. This study aims to contribute to the body of knowledge by examining the buckling responses of sandwich beams or wide plates with an orthotropic anti-tetra chiral lattice (ATCL) aluminum cores and symmetric angle-ply carbon-fiber/epoxy face sheets, both of which can exhibit highly negative Poisson's ratios or extreme auxeticity. The linear stability analysis of the sandwich structures under axial compression is conducted by applying the minimum potential energy principle and solving the eigenvalue problem using a numerical method. To achieve an accurate representation of arbitrary two-dimensional buckling morphologies, the first- and fifth-order shear and normal deformation models are employed to simulate the transverse kinematics of the face sheets and cores, while the finite-element model is utilized to discretize the longitudinal displacement of all constituents. The investigation reveals new insights into the interrelationship between global buckling, facial wrinkling, and shear crimping in conventional sandwich structures. The effects of material auxeticity on buckling responses are analyzed across an extensive range of geometrical configurations for the first time, unveiling five unprecedented buckling mode shapes, sophisticated buckling mode landscapes, and Poisson's ratio-sensitive buckling criteria. These findings lay a crucial foundation for designing and optimizing auxetic sandwich structures, bringing diverse possibilities in lightweight constructions, acoustic insulation, energy absorption, and dynamic and shock mitigation. [ABSTRACT FROM AUTHOR]

Neutrosophic environments have gained significant relevance across diverse disciplines. Neutrosophic Over Supra Exterior Modal Topological Structure is introduced, demonstrating the generation of two distinct structures through traditional Neutrosophic Over supra topological operations, denoted as ... (closure) and ... (interior), along with novel Neutrosophic Over Supra Exterior Modal Operations, expressed as ... (modal closure) and ... (modal interior). This exploration delves into the essential properties and characteristics of these structures, illuminating their behavior and implications. To illustrate the practical relevance, a numerical example is presented, demonstrating the identification of disease types using a score function. The study conclusively shows that the Neutrosophic Over Supra Exterior Modal Topological Structure effectively classifies diseases such as tuberculosis (bacterial), malaria (parasitic), swine flu (viral), and ringworm (fungal). This dual approach ensures a holistic understanding of the topic, appealing to both theoretical and practitioners seeking practical solutions in the neutrosophic over environment. [ABSTRACT FROM AUTHOR]

The study of sorption and diffusion characteristics of glassy polymers based on polyamide‐imides was carried out using the methods of static sorption, dilatometry, electron microscopy. Water sorption isotherms of polyamide‐imides based on trimellitimido‐N‐acetic acid (PAI‐A) and trimellitimido‐N‐p‐benzoic acid (PAI‐B) with different intramolecular 'hinges' in the diamine fragment were obtained. The isotherms are S‐shaped and occupy an intermediate position between polyheteroarylenes and aliphatic polyamides. The dual sorption model was used to interpret the results. It is shown that the Langmuir component of the isotherms is determined by the thermal prehistory of glassy polymers, while the sorption component associated with water dissolution according to Flory‐Huggins is determined by the chemical nature of the functional groups included in the monomeric unit. The diffusion coefficients of water and the temperature and concentration dependences of the diffusion coefficients of sorbed water molecules were determined. [ABSTRACT FROM AUTHOR]

There are conflicting proposals about the underlying structure of the theory of mind (ToM) construct. The lack of clarity impedes attempts to understand relationships between ToM and other cognitive abilities. This study investigated the nature of the ToM construct and its relation to cognitive variables by administering a battery of ToM measurements along with measurements of executive function and general vocabulary to 207 (M age = 19.26) adult participants. Associations between ToM tasks were statistically significant after controlling for covariates, but, for the most part, very weak in magnitude. The strongest relationship was between the Strange Stories and Higher-Order False Belief measurements. Previous theoretical analysis proposes those instruments are conceptually linked by a perspective taking requirement that entails representing another's mental state. Results from a factor analysis suggested an underlying ToM structure—a protagonist perspective factor. The Strange Stories, Higher-Order False Belief, and Frith-Happé Animation tasks loaded onto the factor. Its defining feature is the ascription of mental states to predict and explain protagonists' actions that take place within a narrative structure. It is related more strongly to vocabulary than executive function and it provides grounds for future research on the role of narrative processing in ToM reasoning. [ABSTRACT FROM AUTHOR]

To address the challenges of precision forging for iron seats on railway track, a refined forging method is proposed, involving multiple preforming processes such as arch‐shape reversed bending, warping angle formation, arched shape flattening, warping angle flattening, and reshaping. The dovetail groove in the middle of the iron seat is supposed as a plate structure. Based on the bending and forming theory of plate structure, a physical model of multistep preforming based on reversed bending is first established to analyze the entire forging process, including reversed bending, flattening, and reshaping. Then, focus is placed on studying the neutral stress layer position after the reversed bending during the flattening process of the central dovetail groove, to ensure forging accuracy. The distribution state of the neutral stress layer during the flattening process of the dovetail groove is simulated via professional simulation software Deform; therefore, the position of the neutral stress layer during flattening is plotted. Results show that the theoretical curvature radius of the stress‐neutral layer during the flattening process of arch‐shaped dovetail groove is 33.07 mm, and the stress‐neutral layer is located at 0.37 of the total thickness of the bent plate near the large arc surface, while the simulated neutral layer is at 0.36 of the total thickness of the bent plate near the large arc surface, with an error of only 2.7%. Additionally, at a simulation temperature of 950–1000 °C, the theoretical length of iron seat bottom after flattening is 122.34 mm; meanwhile, the length of the simulated neutral layer at the bottom of the dovetail groove is 122.32 mm, indicating good agreement with its theoretical length. The reversed bending preforming design method not only solves the technical challenges of precision forging for iron seats, but also provides an important reference for the precision forging of other complex structural components. [ABSTRACT FROM AUTHOR]

Ten novel perrhenates of nitrogenous heterocycles have been generated throughout this investigation. The crystal structure of these compounds was thoroughly examined, and intermolecular non-covalent interactions were analysed using the Hirshfeld surface approach. Organic perrhenate cations interact primarily through intermolecular contacts of the H⋯H, O⋯H/H⋯O, and N⋯H/H⋯N types, whereas anions interact mostly via O⋯H/H⋯O interactions. Six of the eight structures with aromatic fragments had anion–π interactions, whereas four of the 11 structures had anion–anion interactions of the Re–O type. Previously unexplored subtypes of 2D networks composed of interacting tetrahedral perrhenate anions have been discovered in piperazinium and triazolium salts. Thermochemical analysis suggests that Re–O⋯Re anion–anion interactions provide additional stabilisation and impact phase transitions in perrhenates. The consistent patterns of organic salt perrhenate behaviour under MALDI-spectrometry settings have been identified. Characteristic multiplets for rhenium acid salts, which can be designated MALDI fingerprints, have been found. Potential formulae of oxorhenates corresponding to the listed multiplets have been specified. [ABSTRACT FROM AUTHOR]

A theoretical foundation for the accurate analysis of the shear‐lag effect in rectangular box‐girder flange slabs is established in this study through the selection of appropriate warping displacement functions. Initially, a series of warping displacement functions that fulfil the basic warping mode of the box‐girder flange slabs is proposed based on the principle of longitudinal warping displacement function setting. Subsequently, the shear‐lag effect, self‐equilibrium condition for shear‐lag warping stress and Timosheko shear deformation are comprehensively considered. The governing differential equations and corresponding natural boundary conditions of the box girder are determined by applying the energy variation principle. The box girder's natural frequency is calculated by solving the governing differential equations under the given warping displacement functions and boundary type. The accuracy of the various warping displacement functions is subsequently evaluated based on the natural frequency values of box girders. A high‐precision longitudinal warping displacement function for box‐girder flange slabs is selected, thus enhancing the analysis precision of the box girders' mechanical properties. Additionally, the necessity of selecting appropriate warping displacement functions is verified through static and dynamic analyses of the box girders. Furthermore, comparisons are made between the finite element solutions and the corresponding analytical solutions utilizing the proposed warping displacement functions, demonstrating the validity of this approach for analysing the box‐girder response. Consequently, the proposed method provides a robust basis for understanding the mechanical properties of rectangular box girders and enriches the existing analytical theory of box structures, guiding the design of rectangular concrete box‐girder bridges. [ABSTRACT FROM AUTHOR]

The Witten–Dijkgraaf–Verlinde–Verlinde (WDVV) equations have a rich structure related to the theory of Frobenius manifolds, with many known families of solutions. A Legendre transformation is a symmetry of the WDVV equations, introduced by Dubrovin. We explicitly compute the results of a Legendre transformation applied to An - and Bn -type multi-parameter rational solutions, relating them to known and new trigonometric solutions. [ABSTRACT FROM AUTHOR]

This work explores the unit graph of the commutative ring Z p for prime p and explores the significance of the Sombor index and the Sombor polynomial in comprehending its structural details. We systematically investigate the unit graph and the identity graph of Z p , exposing subtle patterns and symmetries within its vertices and edges by utilizing the extensive linkages between algebraic structures and graph theory. Using an in-depth examination, we prove the importance of the Sombor index and the Sombor polynomial as indispensable instruments for describing the algebraic and combinatorial characteristics inherent in the graph. Our results clarify the basic characteristics of the unit graph and the identity graph of Z p and highlight its function in expressing the ring's underlying algebraic structure. This work provides an avenue for further investigations into the interplay between algebraic structures and graph-theoretic concepts and also makes contributions to the subject of algebraic graph theory. We clear the path for further research and developments in this fascinating field of study by explaining the complexities regarding the unit and the identity graphs of Z p and emphasizing the significance of the Sombor index and the Sombor polynomial. [ABSTRACT FROM AUTHOR]

There are realist and antirealist interpretations of the free energy principle (FEP). This paper aims to chart out a structural realist interpretation of FEP. To do so, it draws on Worrall's (Dialectica 43(1–2): 99–124, 1989) proposal. The general insight of Worrall's paper is that there is progress at the level of the structure of theories rather than their content. To enact Worrall's strategy in the context of FEP, this paper will focus on characterising the formal continuity between fundamental equations of thermodynamics—such as Boltzmann's equation and Gibbs's equation—on the one hand, and Friston's characterisation of FEP on the other. Lack of a universal consensus on the physical character of entities that feature in thermodynamics, information theory and FEP notwithstanding, I argue that there is structural continuity and unity at the level of mathematical equations that regiment entropy, information and free energy. The existence of such structural continuity and unity provides grounds for structural realism about FEP. [ABSTRACT FROM AUTHOR]

The dispersion, attenuation and bandgap feature of coupled Bloch waves in one-dimensional piezoelectric semiconductor phononic crystal are studied in the present work. In particular, the influences of PN junction are emphasized. Different from the Bloch waves in the piezoelectric phononic crystal, the Bloch wave in piezoelectric semiconductor phononic crystal is attenuated. Moreover, the existence of the carrier fields brings forth more modes of Bloch waves due to the coupling of multiple physical fields. Using the state transfer equation method, the transfer matrix of the unit cell in a one-dimensional piezoelectric semiconductor phononic crystal is derived. Combining this with Bloch theory for periodic structures, the dispersion equation for multi-field coupled Bloch waves is obtained. The dispersion, attenuation and bandgap characteristics of the coupled Bloch waves are then plotted in the complex wave number domain. It is found that the influences of the PN junction are evident and thus provide an enlightenment that the propagation feature of Bloch waves can be adjusted by the control of the PN junction. [ABSTRACT FROM AUTHOR]

In this paper, we give a characterization of the strong degrees of categoricity of computable structures greater or equal to 0 ″ . They are precisely the treeable degrees — the least degrees of paths through computable trees — that compute 0 ″ . As a corollary, we obtain several new examples of degrees of categoricity. Among them we show that every degree d with 0 (α) ≤ d ≤ 0 (α + 1) for α a computable ordinal greater than 2 is the strong degree of categoricity of a rigid structure. Using quite different techniques we show that every degree d with 0 ′ ≤ d ≤ 0 ″ is the strong degree of categoricity of a structure. Together with the above example this answers a question of Csima and Ng. To complete the picture we show that there is a degree d with 0 ′ < d < 0 ″ that is not the degree of categoricity of a rigid structure. [ABSTRACT FROM AUTHOR]

Inconsistencies between (lightweight optical pumped) magnetometers in total field gradiometer surveys can introduce instrument-dependent responses, complicating geological interpretation. Here, we present an equivalent source-based processing method that combines equivalent sources with kernel regression to eliminate these instrument-dependent responses. We evaluate the method using a drone-borne triangular gradiometer survey from Rånbogen, Arctic Norway. The Rånbogen survey exhibits instrument-dependent responses in the measured total field differences, likely resulting from differences in the magnetometer's heading error and the complexities from the induced field from the system itself. A synthetic gradiometer survey was generated to test the method, where different nonlinear synthetic heading errors were added to the synthetic magnetometer readings. The equivalent source-based processing method effectively removed these heading errors while constructing an equivalent source model that fits the actual underlying synthetic model. Furthermore, applying the method to the Rånbogen survey removes the data's correlation to its orientation, thereby minimizing the effect of the instrument-dependent response. The method condenses the gradiometer data to a single equivalent source surface where the derivatives of the total field can be calculated to facilitate interpretation. The results suggest that the equivalent source-based method removes the inconsistencies between the magnetometers in a total field gradiometer survey, allowing for drone-borne gradiometer systems with multiple lightweight magnetometers. [ABSTRACT FROM AUTHOR]

This paper has two objectives: (1) to define philosophical underdetermination in contrast with the usual empirical underdetermination that has been invoked by so many philosophers of science, expanding on recent work in ethics regarding moral underdetermination; (2) to prove that the debate between the causalist and propensionist interpretations of causation in the structure of evolutionary theory is better understood when we consider the two positions philosophically underdetermined. This means that we cannot decide between the two interpretations of the notion of cause implied by natural selection by appealing to scientific practice. If philosophical interpretations of science are underdetermined in the way outlined in this paper, then the only way to move the debate forward is through more thorough philosophical work and theoretical refinements. [ABSTRACT FROM AUTHOR]

The measurement of bite force can be essential for assessing oral health and the functioning of the stomatognathic system. However, its use in dental offices is limited due to operational complexities and costs. This study focused on evaluating the mechanical strength of the user-friendly and low manufacturing cost load cell under development within LABBIO - Bioengineering Laboratory at UFMG, the gnathodynamometer, tailored for children. 3D modeling in SolidWorks and Finite Element Method (FEM) structural analysis were employed to ensure its ability to withstand the desired 1000 N load. Initially, the device did not meet the desired load, resulting in iterations to modify its geometry. After iterations including the replacement of the initial material with a more suitable alternative, removal of edges, and other adjustments, a final prototype meeting mechanical strength and functionality requirements was developed. [ABSTRACT FROM AUTHOR]

This article investigates the incidence of theoretical content in Universal Design. Jones and Gregor's structure of design theory is applied to selected Universal Design works with theoretical content. The Jones and Gregor model of design theory is outlined and explained. Having checked a selection of thirty-seven articles and papers selected for theoretical content, it was found that such content can be fragmentary and not clearly identified. Universal Design work from the Human-Computer Interaction (HCI) field conforms more clearly than other research to Jones and Gregor's structure. This might reflect an unaddressed difference in research philosophies in universal design for products such as assistive technology and accessible product design compared to universal design for HCI. It is concluded that design researchers working on design for disability and universal access need to explicitly identify the structure of their theoretical content. This will aid translation from theory to design practice and to improve theory-building and refinement which is one aim of design research. [ABSTRACT FROM AUTHOR]

Many Americans believe that a breakdown in the "traditional" two‐married‐parent family and the rise in single‐parent families are responsible for persistent family inequality. The general argument is that children do best when they are raised by both biological parents. Evidence increasingly calls into question conventional wisdom about the universal benefits of the two‐parent family, yet mainstream approaches to studying family structure continue to reinforce oversimplistic interpretations of the impact of family structure on well‐being. In this article, we reconsider long‐standing assumptions about the superiority of the heteropatriarchal two‐married‐parent family using historical and contemporary evidence to offset the stagnant theorizing in the study of family structure. We argue that, in pursuit of better science, family researchers must commit to theoretical approaches that move us beyond conventional perspectives of families toward critical perspectives that guide more nuanced, holistic, and contextualized analyses of how family structure actually operates in people's lives. [ABSTRACT FROM AUTHOR]