Geometric Behavior Research Articles

Cognitive Emotional Embedded Representations of Text to Predict Suicidal Ideation and Psychiatric Symptoms

Mathematical modeling of language in Artificial Intelligence is of the utmost importance for many research areas and technological applications. Over the last decade, research on text representation has been directed towards the investigation of dense vectors popularly known as word embeddings. In this paper, we propose a cognitive-emotional scoring and representation framework for text based on word embeddings. This representation framework aims to mathematically model the emotional content of words in short free-form text messages, produced by adults in follow-up due to any mental health condition in the outpatient facilities within the Psychiatry Department of Hospital Fundación Jiménez Díaz in Madrid, Spain. Our contribution is a geometrical-topological framework for Sentiment Analysis, that includes a hybrid method that uses a cognitively-based lexicon together with word embeddings to generate graded sentiment scores for words, and a new topological method for clustering dense vector representations in high-dimensional spaces, where points are very sparsely distributed. Our framework is useful in detecting word association topics, emotional scoring patterns, and embedded vectors’ geometrical behavior, which might be useful in understanding language use in this kind of texts. Our proposed scoring system and representation framework might be helpful in studying relations between language and behavior and their use might have a predictive potential to prevent suicide.

Coupling of SPH and Voronoi-cell lattice models for simulating fluid–structure interaction

In this study, a new methodology for coupling smoothed particle hydrodynamics (SPH) and the Voronoi-cell lattice model (VCLM) is proposed for simulating fluid–structure interaction (FSI). Free-surface flow of the fluid is modeled using SPH; the structural components are modeled by the VCLM, which accounts for both geometric and material nonlinear behaviors. The FSI algorithm is effective regardless of the mesh irregularity, which is validated through numerical simulations of the elastic opening of a dam gate. The simulation results are compared with other numerical and experimental results, which demonstrate the capabilities of the proposed method for FSI problems.

Large amplitude vibrations of imperfect spider web structures

Due to the high-efficiency energy absorption and high-tension strength material properties of spider silk, many researchers have studied the mechanical properties and microstructure of the spider web. The concept of spider web structure has been recognized to be adopted for structural engineering aspect. The structure of spider web and its material properties have been studied for decades. However, the fundamental free vibration mode shapes and their corresponding frequencies have never been fully investigated. This study investigates the nonlinear characteristics in the large-amplitude free vibration of imperfect spider web structures using finite element analysis. The spider web applies the concept of elastic cables taking only axial deformation into account. The finite element models of a spider web considering geometric nonlinearities are employed. It should be noted that spider web could experience large deformation when the spider uses its silk to catch prey. This research aims at analyzing the linear and geometric nonlinear behaviour of imperfect spider web structure. Four different types of imperfect spider web: spiral imperfect spider web, radial imperfect spider web, central imperfect spider web, and circular rings imperfect spider web, are considered. It is found that pretension in spider silk plays a significant role in nonlinear vibration characteristics of the spider web. Moreover, the radial thread damaged tends to have a greater effect on structural free vibration of spider web in comparison with other imperfections. The outcome will help a structural engineer to adapt the concept of spider web, its properties, and damage patterns for any larger structures.

Geometric behavior of a class of algebraic differential equations in a complex domain using a majorization concept

In this paper, a type of complex algebraic differential equations (CADEs) is considered formulating by $ \alpha [\varphi(z) \varphi (z) +(\varphi' (z))^2]+ a_m \varphi^m(z)+a_{m-1} \varphi^{m-1}(z)+...+ a_1 \varphi(z)+ a_0 = 0. $ The conformal analysis (angle-preserving) of the CADEs is investigated. We present sufficient conditions to obtain analytic solutions of the CADEs. We show that these solutions are subordinated to analytic convex functions in terms of $e^z.$ Moreover, we investigate the connection estimates (coefficient bounds) of CADEs by employing the majorization method. We achieve that the coefficients bound are optimized by Bernoulli numbers.

On the Mean Curvature Flow of Submanifolds in the Standard Gaussian Space

In this paper, we study the regular geometric behavior of the mean curvature flow (MCF) of submanifolds in the standard Gaussian metric space $$({{\mathbb {R}}}^{m+p},e^{-|x|^2/m}\overline{g})$$ where $$({{\mathbb {R}}}^{m+p},\overline{g})$$ is the standard Euclidean space and $$x\in {{\mathbb {R}}}^{m+p}$$ denotes the position vector. Note that, as a special Riemannian manifold, $$({{\mathbb {R}}}^{m+p},e^{-|x|^2/m}\overline{g})$$ has an unbounded curvature. Up to a family of diffeomorphisms on $$M^m$$ , the mean curvature flow we considered here turns out to be equivalent to a special variation of the “conformal mean curvature flow” which we have introduced previously. The main theorem of this paper indicates, geometrically, that any immersed compact submanifold in the standard Gaussian space, with the square norm of the position vector being not equal to m, will blow up at a finite time under the mean curvature flow, in the sense that either the position or the curvature blows up to infinity; Moreover, by this main theorem, the interval [0, T) of time in which the flowing submanifolds keep regular has some certain optimal upper bound, and it can reach the bound if and only if the initial submanifold either shrinks to the origin or expands uniformly to infinity under the flow. Besides the main theorem, we also obtain some other interesting conclusions which not only play their key roles in proving the main theorem but also characterize in part the geometric behavior of the flow, being of independent significance.

Failure mechanism analysis of fiber-reinforced polymer composites based on multi-scale fracture plane angles

This paper proposes a physically sound elasto-plastic damage constitutive model, through following Mohr's fracture hypothesis, to characterize pressure sensitivity, nonlinear behaviors and isotropic damage of epoxy matrix materials. Upon the consideration with geometric non-uniformities and mechanical behaviors of constituents, a micromechanical analysis is carried out to study failure mechanisms within fiber-reinforced polymer composite materials applied by different loading scenarios. In particular, special focus is given to the values and distributions of fracture plane angles on multi-scales - the fiber scale and the lamina scale, and therefore both damage scenarios and dominant failure mechanisms are further revealed. The influence of shear nonlinearity of epoxy matrix on overall composite shear responses is assessed from a parametrical study, showing that the composite response induced by longitudinal shear is more susceptible the matrix shear property, when comparing with transverse shear. At last, another use of the proposed micromechanical model is presented. With the use of strength properties and fracture angles captured by micromechanics, the parameters (R⊥At, p⊥⊥t and p⊥⊥c) in Puck's criterion can be computed without making any assumption sometimes arguable. In general, the numerical results regarding homogenized stress-strain responses as well as fracture morphology agree well with experimental measurements and theoretical analyses, validating the predictive capacity of the proposed model.

DAİRESEL BOŞLUKLU KİRİŞLERDE EĞİLME VE YANAL BURULMALI BURKULMA DAVRANIŞININ İNCELENMESİ

3D Finite Element Analysis (FEA) was performed to determine flexural and elastic lateral-torsional buckling behavior of cellular beam by using European steel shape and quality. An experimental study from literature was chosen for verification of the Finite Element Model (FEM). Parametric studies were carried out with a verified numerical model to investigate the effect of some geometrical properties of the cellular beam such as hole diameter, hole spacing, and various types of rigidity plates on elastic buckling and flexural capacity of the beam. Geometric and material nonlinear behavior were included in FEM. In the other part of the study, the theoretical calculation method of Lateral Torsional Buckling (LTB) with gross section and with net section properties was also investigated. The study showed that the LTB calculation method given by AISC360-16 and TSDC-2016 design guides provided more accurate result with net cross-section for European steel shapes and quality.

3D printing of geopolymer-based concrete for building applications

PurposeThree-dimensional (3D) printing technology allows geometric complexity and customization with a significant reduction in the structural environmental impact. Nevertheless, it poses a serious threat to the environment when organic binders are used. Binder jet printing of alkali-activated geopolymer precursor can represent a successful and environmental-friendly alternative.Design/methodology/approachThe present work reports about the successful 3D printing of metakaolin-based alkali-activated concrete, with dimensional integrity and valuable mechanical behavior.FindingsThe geometric behavior was studied as a function of alkali activator flow rate, and the minimum geometric deviation with complete saturation was recorded at 103 mg/s. The printed specimen is characterized by a modulus of rupture as high as 4.4 MPa at 135 mg/s.Practical implicationsThe 3D printed geopolymer-based concrete can be potentially used in a wide range of structural applications from construction to thermal insulation elements.Originality/valueThe analysis of the 3D geopolymer-based concrete printing system and material conducted in this paper is original.

Geometric composition, structural behavior and material design for asphalt trackbed: A review

Asphalt trackbed, as an asphalt-based design below rails, has been increasingly applied with numerous merits in railway substructure. In this paper, a state-of-the-art review is conducted to comprehensively summarize the research and application progress of railway asphalt trackbed, in terms of the typical geometric composition, structural mechanical behavior, and material design. This review indicated that (i) asphalt underlayment (AUL), asphalt overlayment (AOL), surface asphalt mixture impermeable (SAMI) and asphalt stabilized ballast (ASB), as geometry-based classifications are proposed; (ii) load distribution, bearing capacity, vibration control, and moisture resistance, as well as thermal viscoelasticity, are the common mechanical behaviors of AUL and AOL, while the latter more focuses on vibration control, noise reduction, and interlayer contact. For SAMI and ASB, the environmental effects and the bonding strength are more emphasized, respectively; (iii) the material design and construction are normally the same with those of highway asphalt pavement, except for lower air voids but solid wastes as aggregate and lower construction temperature more encouraged. However, the composition of asphalt mixture with high cost-effect and the fatigue behavior considering viscoelastic properties, as well as the rapid construction and maintenance methods on-site need further research.

Influence of welding gases and filler metals on hybrid laser-GMAW and Laser-FCAW welds

Hybrid Laser-Arc Welding (HLAW) is a relatively new joining technique that combines advantages from both laser beam welding and arc welding. The interaction between laser beam and arc welding provides advantageous synergic effects, especially for thick joints. On the other hand, this interaction brings extra complexity to HLAW, limiting its acceptance in industry. Therefore, it is still necessary to elucidate some features of HLAW, such as the influence of parameters and consumables on the characteristics of the resulting joints. In the present study, the effects of welding gases (Ar + CO2 in different proportions) and filler metals (solid and flux-cored wires) on thick S355 structural steel joints are assessed. The best welds in terms of geometric characteristics, microstructures, and mechanical behavior were fabricated with high CO2 content welding gases and flux-cored welding wires. The use of flux-cored wires promoted higher penetration, lower hardness, and formation of acicular ferrite, avoiding the formation of martensite encountered in joints welded with solid wires. Moreover, the application of flux-cored wires could lead to cost savings in future applications, by reducing the laser power required to produce sound joints.

Traversable wormhole modelling with exponential and hyperbolic shape functions in F(R,T) framework

The concept of traversable wormhole, a hypothetical tunnel-like structure is initially proposed by Morris and Thorne (Am. J. Phys. 56, 395 (1988)) by using Einstein’s general relativity theory. Harko et al. (Phys. Rev. D 84, 024020 (2011)) defined [Formula: see text] gravity as an extended gravitational theory having terms [Formula: see text] and [Formula: see text] as Ricci scalar and trace of energy momentum respectively. In this article, we explore wormhole models for the framework of [Formula: see text] gravity by using two different shape functions. The first shape function is [Formula: see text], [Formula: see text] (proposed by Mishra and Sharma, arXiv:2003.00298v1 , 2020) and second is a hyperbolic shape function which is of the form [Formula: see text]. Geometrical behavior of wormholes are discussed in anisotropic scenario by using equation of state [Formula: see text]. The stability of models are analyzed by using equilibrium condition and determining gravitational force, anisotropic force, hydrostatic force and force due to modified gravity. For the validation of null energy condition and weak energy condition, significant role of shape function is illustrated for the presence of nonexotic matter.

Numerical-Computational Model for Nonlinear Analysis of Frames with Semirigid Connection

A numerical-computational model for static analysis of plane frames with semirigid connections and geometric nonlinear behavior is presented. The set of nonlinear equations governing the structural system is solved by the Potra–Pták method in an incremental procedure, with order of cubic convergence, combined with the linear arc-length path-following technique. The algorithm pseudo-code is presented, and the finite element corotational method is used for the discretization of the structures. The equilibrium paths with load and displacement limit points are obtained. The semirigidity is simulated by a linear connection element of null length, which considers the axial, tangential, and rotational stiffness. Nonlinear analyses of 2D frame structures are carried out with the free Scilab program. The results show that the Potra–Pták procedure can decrease the number of iterations and the computing time in comparison with the standard and modified Newton–Raphson iterative schemes. Also, the simulations show that the connection flexibility has a strong influence on the nonlinear behavior and stability of the structural systems.

Large-Amplitude Vibrations of Spider Web Structures

Spider silk, as a natural material, shows exceptional performance in its properties. The combination of the superior properties of spider silk and the geometry of spider structures make the spider web very resilient. A spider web structure can be considered as a cable-like structure with inappreciable torsional, bending and shear rigidities. An investigation emphasising on natural frequencies and corresponding mode shapes with and without the consideration of geometric nonlinearity is presented in this paper. This study is the world’s first discovery of large amplitude free vibration behaviours of spider web structures. Large deformable finite element 3D models of spider web structures have been developed and validated. By using the energy method, the variational model of the spider web structures have been established to further extend the finite element model, consisting of the strain energy due to axial deformation, kinetic energy due to the spider web movement and the virtual work caused by the self-weight per unit unstretched length. The emphasis of this study is placed on the linear and geometric nonlinear behaviour of the spider web structures considering different structural patterns and material properties. To determine the large-amplitude free vibrational behaviours, a series of pretension load is applied to the first step in Abaqus to initiate the nonlinear strain-displacement relationships enabling a precursor to free vibrations. The parametric studies stemming from structural patterns (the number of radial and capture threads), elastic modulus, density, and inertia moment have been highlighted. The insight will help engineers and scientists to adapt the concept of spider webs, their geometric properties, and damage patterns for the design of any structural membranes, preventing any failure from dynamic resonances and nonlinear phenomena.

Geometric Non-Linear Analysis of Auxetic Hybrid Laminated Beams Containing CNT Reinforced Composite Materials.

In the current work, a novel hybrid laminate with negative Poisson’s ratio (NPR) is developed by considering auxetic laminate which is composed of carbon nanotube-reinforced composite (CNTRC) and fiber-reinforced composite (FRC) materials. The maximum magnitude of out-of-plane NPR is identified in the case of (20 F/20 C/−20 C/20 C) S laminate as well. Meanwhile, a method for the geometric non-linear analysis of hybrid laminated beam with NPR including the non-linear bending, free, and forced vibrations is proposed. The beam deformation is modeled by combining higher-order shear-deformation theory (HSDT) and large deflection theory. Based on a two-step perturbation approach, the asymptotic solutions of the governing equations are obtained to capture the linear and non-linear frequencies and load-deflection curves. Moreover, a two-step perturbation methodology in conjunction with fourth-order Runge–Kutta method is employed to solve the forced-vibration problem. Several key factors, such as CNT distribution, variations in the elastic foundation, and thermal stress, are considered in the exhaustive analysis. Theoretical results for some particular cases are given to examine the geometric non-linearity behavior of hybrid beam with NPR as well as positive Poisson’s ratio (PPR).

Molecular dynamics simulation of laser-induced interconnections of silver nanowires

In this paper, the geometric deformation and atomic behavior evolution of silver nanowires subjected to laser are simulated by non-equilibrium molecular dynamics method. The simulation results show that due to the surface plasma resonance effect of the laser, significant atomic diffusion occurs in the contact area of the two silver nanowires. With the increase of the irradiation time of the laser, the atomic diffusion becomes more and more significant, and finally the two nanowires are connected. Because it is realized in plasma resonance under the action of the connection, and diffusion joint can produce stress due to atomic focus, the stress led to the nanowire outer atomic force by the inward contraction, completely different from the whole heating lead to the phenomenon of melting, diffusion, refactoring, produce similar to the form of cold welding joint, the joint can build complete face-centered cubic lattice structure, so the laser induced nanowires connect will complete nanowires of retention of the original structure and has superior properties of the nanowires interconnect technology will become the trend of The Times, It’s the most important piece of the puzzle for building the next generation of nanodevices.

Low-cost experimental apparatus for motion tracking based on image processing and camera calibration techniques

The present work focuses on the use of a low-cost equipment to monitor static and dynamic tests as an alternative to expensive commercial devices. First, we describe a procedure for cameras calibration and image processing in order to establish a less invasive (than other common instrumentation, such as strain gauges) and much cheaper motion capture method (than commercial tracking systems). Following, two cameras and one personal computer (with an image acquisition board) are used as the monitoring apparatus for tracking the movements of a flexible cable under harmonic excitation at its top end. The experimental results are then compared with numerical simulations, showing a fairly good agreement and the same level of precision as that obtained with one of the most used motion capture system in laboratories. The proposed experimental methodology correctly identifies the displacements, frequencies, and dynamic geometric behavior of the flexible model in all directions. Although commercial solutions are faster, since data processing and cameras calibration take place in real time, the acquisition cost of the suggested equipment is most affordable for small industries, educational institutions and projects with restrict budget on kinesiology, physiology, dentistry, facial recognition and mechanics, among others.

How Lanthanide Ions Affect the Addition-Elimination Step of Methanol Dehydrogenases.

The recently discovered methanol dehydrogenase, XoxF, is a widespread enzyme used by methylotrophic bacteria to oxidize methanol for carbon and energy, and requires lanthanide ions for its activity. This enzyme represents an essential component of methanol utilization by both methanol- and methane-utilizing bacteria. The present investigation looks on the electronic, energetic and geometrical behavior of the methanol dehydrogenase from Methylacidiphilum fumariolicum SolV, which is strictly dependent on early lanthanide metals with +3 oxidation states, by examining enzyme-substrate complexes of all the lanthanides. We focus on the catalytic reaction mechanism of two methanol dehydrogenases having as cofactor europium and ytterbium belonging to the mid- and later- series of lanthanides, in comparison with the methanol dehydrogenase containing the cerium, one early lanthanide. Our results provide evidence for the influence of the lanthanide contraction effect in all the elementary steps of the catalytic reaction mechanism. This indication may prove useful for developing new catalytic machineries of enzymes that adopt new-to-nature transformations.

A Comparative Study of the Pliability of Separate Auxetic Architectonic Structures by Means of CAD

If a lengthened structure gets fat in all directions and the same structure gets narrower when it is pressed, it is an auxetic structure. This happens because these kinds of structures have a negative Poisson's ratio (NPR). In this paper a comparative study of unity patterns of CAD auxetic geometries is presented. A Computer Aided Design library of auxetic geometries will be developed to apply them to architecture. The geometric behavior of the eighteen auxetic separate patterns is tested from the developed library in order to develop a systematic comparison, analyzing properties of these forms, such as their maximum achievable area reductions in relation with the total length of bars of the structure, in order to obtain a growth factor.

Computerized design, simulation of meshing and stress analysis of pure rolling cylindrical helical gear drives with variable helix angle

The geometric design, meshing performance, and mechanical behavior of pure rolling cylindrical helical gear drives with variable helix angle are preseted. This new type of pure rolling gear drives are based on the active design of the meshing line function. Seven types including linear, parabolic, and combined meshing line functions with variable helix angle and parametric equations for convex-to-convex meshing type are discussed. The contact patterns, loaded functions of transmission errors, and the evolution of contact and bending stresses along two pitch angles of rotation of the pinion being evaluated are compared to each other and to a pair of non-standard involute helical gears. Results show that one of the cases of design of pure rolling helical gears with variable helix angle reduces bending and contact stresses compared to the case of pure rolling helical gears with constant helix angle. Compared to involute helical gear drive, contact and bending stresses are increased. However, pure rolling cylindrical helical gears show potential for application as plastic gears in which their complex geometry can be reproduced with injection molding and the phenomenon of pure rolling meshing would contribute to a low heat generation and durability of the gears.

Process-independent construction stage analysis of self-anchored suspension bridges

The construction process of self-anchored suspension (SAS) bridges undergoes frequent system transformations and loadings, accompanied by complex strong geometric and contact nonlinear behaviours. The accurate state assessment of such a process generally requires the nonlinear finite element analysis (FEA) to perform a stage-by-stage forward, cumulative calculation based on the principle of incremental superposition. This sort of calculation means that the structural equilibrium of any intermediate state of the process, referred to as a construction stage, must be accumulated from its previous construction loading history, which is susceptible to computational effort and divergence limitations. This paper overcomes these limitations by proposing a direct and fast method that is independent of the cumulative calculation in the analysis of any specified construction stage, in favour of the construction optimization design and uncertainty analysis. The unstrained assembly formats for the typical construction process of SAS bridges are established, and the elements with constant physical quantities as the characteristic parameters are used to describe the various structures, boundaries, loads and their changes during the construction. On this basis, an interactive analysis framework integrating the numerical iteration with the FEA is established to achieve an accurate equilibrium for the construction stages. An enhanced interval-genetic algorithm (IGA) is employed as the optimization engine to smoothly accelerate global convergence. The proposed framework is applied to an SAS bridge under construction, and the validity and performance of this approach are demonstrated by considering the in-field test data.