
显示样式: 排序: IF: - GO 导出
-
On non-autonomous differential-difference AKP, BKP and CKP equations Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 Wei Fu; Frank W. Nijhoff
Based on the direct linearization framework of the discrete Kadomtsev–Petviashvili-type equations presented in the work of Fu & Nijhoff (Fu W, Nijhoff FW. 2017 Direct linearizing transform for three-dimensional discrete integrable systems: the lattice AKP, BKP and CKP equations. Proc. R. Soc. A473, 20160915 (doi:10.1098/rspa.2016.0915)), six novel non-autonomous differential-difference equations are
-
Granular size segregation in silos with and without inserts Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 A. Cliff; L. A. Fullard; E. C. P. Breard; J. Dufek; C. E. Davies
The storage of granular materials is a critical process in industry, which has driven research into flow in silos. Varying material properties, such as particle size, can cause segregation of mixtures. This work seeks to elucidate the effects of size differences and determine how using a flow-correcting insert mitigates segregation during silo discharge. A rotating table was used to collect mustard
-
Elastic multi-blisters induced by geometric constraints Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 D. De Tommasi; G. Devillanova; F. Maddalena; G. Napoli; G. Puglisi
We study a prototypical system describing instability effects due to geometric constraints in the framework of nonlinear elasticity. By considering the equilibrium configurations of an elastic ring constrained inside a rigid circle with smaller radius, we analytically determine different possible shapes, reproducing well-known physical phenomena. As we show, both single- (with different complexity)
-
Complementary roles of mechanotransduction and inflammation in vascular homeostasis Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 Marcos Latorre; Bart Spronck; Jay D. Humphrey
Arteries are exposed to relentless pulsatile haemodynamic loads, but via mechanical homeostasis they tend to maintain near optimal structure, properties and function over long periods in maturity in health. Numerous insults can compromise such homeostatic tendencies, however, resulting in maladaptations or disease. Chronic inflammation can be counted among the detrimental insults experienced by arteries
-
Breakdown of similarity solutions: a perturbation approach for front propagation during foam-improved oil recovery Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 Carlos Torres-Ulloa; Paul Grassia
The pressure-driven growth model has been employed to study a propagating foam front in the foam-improved oil recovery process. A first-order solution of the model proves the existence of a concave corner on the front, which initially migrates downwards at a well defined speed that differs from the speed of front material points. At later times, however, it remains unclear how the concave corner moves
-
Tunable mechanical diode of nonlinear elastic metamaterials induced by imperfect interface Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 Zhen-Ni Li; Yi-Ze Wang; Yue-Sheng Wang
In this investigation, the non-reciprocal transmission in a nonlinear elastic metamaterial with imperfect interfaces is studied. Based on the Bloch theorem and stiffness matrix method, the band gaps and transmission coefficients with imperfect interfaces are obtained for the fundamental and double frequency cases. The interfacial influences on the transmission behaviour are discussed for both the nonlinear
-
Evolution of spray and aerosol from respiratory releases: theoretical estimates for insight on viral transmission Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 P. M. de Oliveira; L. C. C. Mesquita; S. Gkantonas; A. Giusti; E. Mastorakos
By modelling the evaporation and settling of droplets emitted during respiratory releases and using previous measurements of droplet size distributions and SARS-CoV-2 viral load, estimates of the evolution of the liquid mass and the number of viral copies suspended were performed as a function of time from the release. The settling times of a droplet cloud and its suspended viral dose are significantly
-
Wireless power distributions in multi-cavity systems at high frequencies Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-20 Farasatul Adnan; Valon Blakaj; Sendy Phang; Thomas M. Antonsen; Stephen C. Creagh; Gabriele Gradoni; Gregor Tanner
The next generations of wireless networks will work in frequency bands ranging from sub-6 GHz up to 100 GHz. Radio signal propagation differs here in several critical aspects from the behaviour in the microwave frequencies currently used. With wavelengths in the millimetre range (mmWave), both penetration loss and free-space path loss increase, while specular reflection will dominate over diffraction
-
Understanding the role of urban design in disease spreading Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-13 Noel G. Brizuela; Nstor Garca-Chan; Humberto Gutirrez Pulido; Gerardo Chowell
Cities are complex systems whose characteristics impact the health of people who live in them. Nonetheless, urban determinants of health often vary within spatial scales smaller than the resolution of epidemiological datasets. Thus, as cities expand and their inequalities grow, the development of theoretical frameworks that explain health at the neighbourhood level is becoming increasingly critical
-
Revisiting imperfect interface laws for two-dimensional elastodynamics Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-13 Kim Pham; Agns Maurel; Jean-Jacques Marigo
We study the interaction of in-plane elastic waves with imperfect interfaces composed of a periodic array of voids or cracks. An effective model is derived from high-order asymptotic analysis based on two-scale homogenization and matched asymptotic technique. In two-dimensional elasticity, we obtain jump conditions set on the in-plane displacements and normal stresses; the jumps involve in addition
-
High-resolution thickness maps of corrosion using SH1 guided wave tomography Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-13 Andreas A. E. Zimmermann; Peter Huthwaite; Brian Pavlakovic
Quantifying corrosion damage is vital for the petrochemical industry, and guided wave tomography can provide thickness maps of such regions by transmitting guided waves through these areas and capturing the scattering information using arrays. The dispersive nature of the guided waves enables a reconstruction of wave velocity to be converted into thickness. However, existing approaches have been shown
-
Numerical calculation of N-periodic wave solutions to coupled KdVToda-type equations Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-13 Yingnan Zhang; Xingbiao Hu; Jianqing Sun
In this paper, we study the N-periodic wave solutions of coupled Korteweg–de Vries (KdV)–Toda-type equations. We present a numerical process to calculate the N-periodic waves based on the direct method of calculating periodic wave solutions proposed by Akira Nakamura. Particularly, in the case of N = 3, we give some detailed examples to show the N-periodic wave solutions to the coupled Ramani equation
-
The mathematical foundations of anelasticity: existence of smooth global intermediate configurations Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Christian Goodbrake; Alain Goriely; Arash Yavari
A central tool of nonlinear anelasticity is the multiplicative decomposition of the deformation tensor that assumes that the deformation gradient can be decomposed as a product of an elastic and an anelastic tensor. It is usually justified by the existence of an intermediate configuration. Yet, this configuration cannot exist in Euclidean space, in general, and the mathematical basis for this assumption
-
Topological charges and conservation laws involving an arbitrary function of time for dynamical PDEs Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Stephen C. Anco; Elena Recio
Dynamical PDEs that have a spatial divergence form possess conservation laws that involve an arbitrary function of time. In one spatial dimension, such conservation laws are shown to describe the presence of an x-independent source/sink; in two and more spatial dimensions, they are shown to produce a topological charge. Two applications are demonstrated. First, a topological charge gives rise to an
-
First-order convergence of Milstein schemes for McKeanVlasov equations and interacting particle systems Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Jianhai Bao; Christoph Reisinger; Panpan Ren; Wolfgang Stockinger
In this paper, we derive fully implementable first-order time-stepping schemes for McKean–Vlasov stochastic differential equations, allowing for a drift term with super-linear growth in the state component. We propose Milstein schemes for a time-discretized interacting particle system associated with the McKean–Vlasov equation and prove strong convergence of order 1 and moment stability, taming the
-
A new approach to integrable evolution equations on the circle Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 A. S. Fokas; J. Lenells
We propose a new approach for the solution of initial value problems for integrable evolution equations in the periodic setting based on the unified transform. Using the nonlinear Schrödinger equation as a model example, we show that the solution of the initial value problem on the circle can be expressed in terms of the solution of a Riemann–Hilbert problem whose formulation involves quantities which
-
Using adjoint-based optimization to enhance ignition in non-premixed jets Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Ubaid Ali Qadri; Luca Magri; Matthias Ihme; Peter J. Schmid
Gradient-based optimization is used to reliably and optimally induce ignition in three examples of laminar non-premixed mixture configurations. Using time-integrated heat release as a cost functional, the non-convex optimization problem identified optimal energy source locations that coincide with the stoichiometric local mixture fraction surface for short optimization horizons, while for longer horizons
-
An agent-based model of the interrelation between the COVID-19 outbreak and economic activities Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Takeshi Kano; Kotaro Yasui; Taishi Mikami; Munehiro Asally; Akio Ishiguro
As of July 2020, COVID-19 caused by SARS-COV-2 is spreading worldwide, causing severe economic damage. While minimizing human contact is effective in managing outbreaks, it causes severe economic losses. Strategies to solve this dilemma by considering the interrelation between the spread of the virus and economic activities are urgently needed to mitigate the health and economic damage. Here, we propose
-
Psychophysical study of the moon illusion in paintings and landscape photos Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Zoltn Kovcs; Zoltn Udvarnoki; Eszter Papp; Gbor Horvth
The moon illusion is a visual deception when people perceive the angular diameter of the Moon/Sun near the horizon larger than that of the one higher in the sky. Some theories have been proposed to explain this illusion, but not any is generally accepted. Although several psychophysical experiments have been performed to study different aspects of the moon illusion, their results have sometimes contradicted
-
M-theory, black holes and cosmology Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Renata Kallosh
This paper is dedicated to Michael J. Duff on the occasion of his 70th birthday. I discuss some issues of M-theory/string theory/supergravity closely related to Mike’s interests. I describe a relation between STU black hole entropy, the Cayley hyperdeterminant, the Bhargava cube and a three-qubit Alice–Bob–Charlie triality symmetry. I shortly describe my recent work with Gunaydin, Linde and Yamada
-
Analytical continuation of two-dimensional wave fields Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2021-01-06 Raphal C. Assier; Andrey V. Shanin
Wave fields obeying the two-dimensional Helmholtz equation on branched surfaces (Sommerfeld surfaces) are studied. Such surfaces appear naturally as a result of applying the reflection method to diffraction problems with straight scatterers bearing ideal boundary conditions. This is for example the case for the classical canonical problems of diffraction by a half-line or a segment. In the present
-
Heavy-tailed distributions, correlations, kurtosis and Taylors Law of fluctuation scaling Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Joel E. Cohen; Richard A. Davis; Gennady Samorodnitsky
Pillai & Meng (Pillai & Meng 2016 Ann. Stat.44, 2089–2097; p. 2091) speculated that ‘the dependence among [random variables, rvs] can be overwhelmed by the heaviness of their marginal tails ·· ·’. We give examples of statistical models that support this speculation. While under natural conditions the sample correlation of regularly varying (RV) rvs converges to a generally random limit, this limit
-
A statistical theory of the strength of epidemics: an application to the Italian COVID-19 case Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Gabriele Pisano; Gianni Royer-Carfagni
The proposed theory defines a relative index of epidemic lethality that compares any two configurations in different observation periods, preferably one in the acute and the other in a mild epidemic phase. Raw mortality data represent the input, with no need to recognize the cause of death. Data are categorized according to the victims’ age, which must be renormalized because older people have a greater
-
Response theory and phase transitions for the thermodynamic limit of interacting identical systems Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Valerio Lucarini; Grigorios A. Pavliotis; Niccol Zagli
We study the response to perturbations in the thermodynamic limit of a network of coupled identical agents undergoing a stochastic evolution which, in general, describes non-equilibrium conditions. All systems are nudged towards the common centre of mass. We derive Kramers–Kronig relations and sum rules for the linear susceptibilities obtained through mean field Fokker–Planck equations and then propose
-
Three-phase flow displacement dynamics and Haines jumps in a hydrophobic porous medium Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Abdulla Alhosani; Alessio Scanziani; Qingyang Lin; Ahmed Selem; Ziqing Pan; Martin J. Blunt; Branko Bijeljic
We use synchrotron X-ray micro-tomography to investigate the displacement dynamics during three-phase—oil, water and gas—flow in a hydrophobic porous medium. We observe a distinct gas invasion pattern, where gas progresses through the pore space in the form of disconnected clusters mediated by double and multiple displacement events. Gas advances in a process we name three-phase Haines jumps, during
-
Violations of the ClausiusDuhem inequality in Couette flows of granular media Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Martin Ostoja-Starzewski; Rossella Laudani
Spontaneous violations of the Clausius–Duhem (CD) inequality in Couette-type collisional flows of model granular media are studied. Planar systems of monosized circular discs (with disc numbers from 10 to 204, and disc diameters from 0.001 m to 1 m) with frictional-Hookean contacts are simulated under periodic boundary conditions by a molecular dynamics. The scale-dependent homogenization of micropolar
-
Absence of diagonal force constants in cubic Coulomb crystals Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Bartholomew Andrews; Gareth Conduit
The quasi-harmonic model proposes that a crystal can be modelled as atoms connected by springs. We demonstrate how this viewpoint can be misleading: a simple application of Gauss’s law shows that the ion–ion potential for a cubic Coulomb system can have no diagonal harmonic contribution and so cannot necessarily be modelled by springs. We investigate the repercussions of this observation by examining
-
Capillary transport in paper porous materials at low saturation levels: normal, fast or superfast? Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Alex V. Lukyanov; Vladimir V. Mitkin; Tristan Pryer; Penpark Sirimark; Theo G. Theofanous
The problem of capillary transport in fibrous porous materials at low levels of liquid saturation has been addressed. It has been demonstrated that the process of liquid spreading in this type of porous material at low saturation can be described macroscopically by a similar super-fast, nonlinear diffusion model to that which had been previously identified in experiments and simulations in particulate
-
Diffusion in arrays of obstacles: beyond homogenization Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Yahya Farah; Daniel Loghin; Alexandra Tzella; Jacques Vanneste
We revisit the classical problem of diffusion of a scalar (or heat) released in a two-dimensional medium with an embedded periodic array of impermeable obstacles such as perforations. Homogenization theory provides a coarse-grained description of the scalar at large times and predicts that it diffuses with a certain effective diffusivity, so the concentration is approximately Gaussian. We improve on
-
Radio-frequency chain selection for energy and spectral efficiency maximization in hybrid beamforming under hardware imperfections Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Evangelos Vlachos; John Thompson; Aryan Kaushik; Christos Masouros
The next-generation wireless communications require reduced energy consumption, increased data rates and better signal coverage. The millimetre-wave frequency spectrum above 30 GHz can help fulfil the performance requirements of the next-generation mobile broadband systems. Multiple-input multiple-output technology can provide performance gains to help mitigate the increased path loss experienced at
-
Matrix models and deformations of JT gravity Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-23 Edward Witten
Recently, it has been found that Jackiw-Teitelboim (JT) gravity, which is a two-dimensional theory with bulk action −1/2∫d2xgϕ(R+2), is dual to a matrix model, that is, a random ensemble of quantum systems rather than a specific quantum mechanical system. In this article, we argue that a deformation of JT gravity with bulk action −1/2∫d2xg(ϕR+W(ϕ)) is likewise dual to a matrix model. With a specific
-
Modelling foam improved oil recovery: towards a formulation of pressure-driven growth with flow reversal Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 M. Eneotu; P. Grassia
The pressure-driven growth model that describes the two-dimensional (2-D) propagation of a foam through an oil reservoir is considered as a model for surfactant-alternating-gas improved oil recovery. The model assumes a region of low mobility, finely textured foam at the foam front where injected gas meets liquid. The net pressure driving the foam is assumed to reduce suddenly at a specific time. Parts
-
Overcoming the curse of dimensionality in the numerical approximation of semilinear parabolic partial differential equations Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Martin Hutzenthaler; Arnulf Jentzen; Thomas Kruse; Tuan Anh Nguyen; Philippe von Wurstemberger
For a long time it has been well-known that high-dimensional linear parabolic partial differential equations (PDEs) can be approximated by Monte Carlo methods with a computational effort which grows polynomially both in the dimension and in the reciprocal of the prescribed accuracy. In other words, linear PDEs do not suffer from the curse of dimensionality. For general semilinear PDEs with Lipschitz
-
The Born rule as a statistics of quantum micro-events Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Yurii V. Brezhnev
We deduce the Born rule from a purely statistical take on quantum theory within minimalistic math-setup. No use is required of quantum postulates. One exploits only rudimentary quantum mathematics—a linear, not Hilbert’, vector space—and empirical notion of the Statistical Length of a state. Its statistical nature comes from the lab micro-events (detector-clicks) being formalized into the C-coefficients
-
High-frequency homogenization in periodic media with imperfect interfaces Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Raphal C. Assier; Marie Touboul; Bruno Lombard; Cdric Bellis
In this work, the concept of high-frequency homogenization is extended to the case of one-dimensional periodic media with imperfect interfaces of the spring-mass type. In other words, when considering the propagation of elastic waves in such media, displacement and stress discontinuities are allowed across the borders of the periodic cell. As is customary in high-frequency homogenization, the homogenization
-
Control of connectivity and rigidity in prismatic assemblies Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Gary P. T. Choi; Siheng Chen; Lakshminarayanan Mahadevan
How can we manipulate the topological connectivity of a three-dimensional prismatic assembly to control the number of internal degrees of freedom and the number of connected components in it? To answer this question in a deterministic setting, we use ideas from elementary number theory to provide a hierarchical deterministic protocol for the control of rigidity and connectivity. We then show that it
-
Plasmonic modes in cylindrical nanoparticles and dimers Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Charles A. Downing; Guillaume Weick
We present analytical expressions for the resonance frequencies of the plasmonic modes hosted in a cylindrical nanoparticle within the quasi-static approximation. Our theoretical model gives us access to both the longitudinally and transversally polarized dipolar modes for a metallic cylinder with an arbitrary aspect ratio, which allows us to capture the physics of both plasmonic nanodisks and nanowires
-
Nonlinear generalized functions on manifolds Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 E. A. Nigsch; J. A. Vickers
In this work, we adopt a new approach to the construction of a global theory of algebras of generalized functions on manifolds based on the concept of smoothing operators. This produces a generalization of previous theories in a form which is suitable for applications to differential geometry. The generalized Lie derivative is introduced and shown to extend the Lie derivative of Schwartz distributions
-
A nonlinear theory of distributional geometry Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 E. A. Nigsch; J. A. Vickers
This paper builds on the theory of nonlinear generalized functions begun in Nigsch & Vickers (Nigsch, Vickers 2021 Proc. R. Soc. A 20200640 (doi:10.1098/rspa.2020.0640)) and extends this to a diffeomorphism-invariant nonlinear theory of generalized tensor fields with the sheaf property. The generalized Lie derivative is introduced and shown to commute with the embedding of distributional tensor fields
-
Fibrous gels modelled as fluid-filled continua with double-well energy landscape Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Chuanpeng Sun; Irina N. Chernysh; John W. Weisel; Prashant K. Purohit
Several biological materials are fibre networks infused with fluid, often referred to as fibrous gels. An important feature of these gels is that the fibres buckle under compression, causing a densification of the network that is accompanied by a reduction in volume and release of fluid. Displacement-controlled compression of fibrous gels has shown that the network can exist in a rarefied and a densified
-
A duality between scattering poles and transmission eigenvalues in scattering theory Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-16 Fioralba Cakoni; David Colton; Houssem Haddar
In this paper, we develop a conceptually unified approach for characterizing and determining scattering poles and interior eigenvalues for a given scattering problem. Our approach explores a duality stemming from interchanging the roles of incident and scattered fields in our analysis. Both sets are related to the kernel of the relative scattering operator mapping incident fields to scattered fields
-
Macroscopic permeability of doubly porous solids with spheroidal macropores: closed-form approximate solutions of the longitudinal permeability Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-09 Vincent monchiet
The presence of macropores and fractures significantly affects the effective transport properties of porous solids such as concrete and rocks. The dimensions of the fractures are generally large behind that of the initial porosity, so that the problem contains two porosities. The influence of the macroporosity is studied in the homogenization framework by solving at the intermediate scale, that of
-
Dynamics of a waveboard simplified Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-09 Anirvan DasGupta
A study of dynamics of a waveboard is presented. The equations of motion are derived and analysed to understand the intriguing propulsion mechanism. A reduced order model is obtained, and the contributions of different terms are clearly brought out. The geometry of the castor wheels is found to play a key role in the conversion of the twisting oscillatory motion of the rider to the forward translational
-
A revisit of the tonal noise of small rotors Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-09 Siyang Zhong; Peng Zhou; Ryu Fattah; Xin Zhang
In this study, asymptotic analysis of the frequency-domain formulation to compute the tonal noise of the small rotors in the now ubiquitously multi-rotor powered drones is conducted. Simple scaling laws are proposed to evaluate the impacts of the influential parameters such as blade number, flow speed, rotation speed, unsteady motion, thrust and observer angle on the tonal noise. The rate of noise
-
Non-reciprocal acoustics in a viscous environment Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-09 Hyeonu Heo; Ezekiel Walker; Yurii Zubov; Dmitrii Shymkiv; Dylan Wages; Arkadii Krokhin; Tae-Youl Choi; Arup Neogi
It is demonstrated that acoustic transmission through a phononic crystal with anisotropic solid scatterers becomes non-reciprocal if the background fluid is viscous. In an ideal (inviscid) fluid, the transmission along the direction of broken P symmetry is asymmetric. This asymmetry is compatible with reciprocity since time-reversal symmetry (T symmetry) holds. Viscous losses break T symmetry, adding
-
Maxwell's quasi-demon as a property of an ideal gas in the equilibrium state Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-12-02 Andrey V. Semikolenov
The paper shows that for the case of an ideal gas in the equilibrium state there exists a method for splitting it into portions with different temperatures without energy transfer to or from the environment and without work being done. Compared with the thought experiment known as ‘Maxwell's demon’, in which such splitting is based on sorting specific molecules according to their energy levels, the
-
Superdeterministic hidden-variables models II: conspiracy Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Indrajit Sen; Antony Valentini
We prove that superdeterministic models of quantum mechanics are conspiratorial in a mathematically well-defined sense, by further development of the ideas presented in a previous article A. We consider a Bell scenario where, in each run and at each wing, the experimenter chooses one of N devices to determine the local measurement setting. We prove, without assuming any features of quantum statistics
-
Analysis of node2vec random walks on networks Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Lingqi Meng; Naoki Masuda
Random walks have been proven to be useful for constructing various algorithms to gain information on networks. Algorithm node2vec employs biased random walks to realize embeddings of nodes into low-dimensional spaces, which can then be used for tasks such as multi-label classification and link prediction. The performance of the node2vec algorithm in these applications is considered to depend on properties
-
Environmental sustainability of biofuels: a review Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Harish K. Jeswani; Andrew Chilvers; Adisa Azapagic
Biofuels are being promoted as a low-carbon alternative to fossil fuels as they could help to reduce greenhouse gas (GHG) emissions and the related climate change impact from transport. However, there are also concerns that their wider deployment could lead to unintended environmental consequences. Numerous life cycle assessment (LCA) studies have considered the climate change and other environmental
-
Oscillatory dynamics in the dilemma of social distancing Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Alina Glaubitz; Feng Fu
Social distancing as one of the main non-pharmaceutical interventions can help slow down the spread of diseases, like in the COVID-19 pandemic. Effective social distancing, unless enforced as drastic lockdowns and mandatory cordon sanitaire, requires consistent strict collective adherence. However, it remains unknown what the determinants for the resultant compliance of social distancing and their
-
Electrocharged facepiece respirator fabrics using common materials Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 M. M. Bandi
Face masks in general, and N95 filtering facepiece respirators (FRs) that protect against SARS-Cov-2 virion in particular, have become scarce during the ongoing COVID-19 global pandemic. This work presents practical design principles for the fabrication of electrocharged filtration layers employed in N95 FRs using commonly available materials and easily replicable methods. The input polymer is polypropylene
-
An improved statistical approach for reconstructing past climates from biotic assemblages Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Mengmeng Liu; Iain Colin Prentice; Cajo J. F. ter Braak; Sandy P. Harrison
Quantitative reconstructions of past climates are an important resource for evaluating how well climate models reproduce climate changes. One widely used statistical approach for making such reconstructions from fossil biotic assemblages is weighted averaging partial least-squares regression (WA-PLS). There is however a known tendency for WA-PLS to yield reconstructions compressed towards the centre
-
Diffraction by a rigid strip in a plate modelled by Mindlin theory Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Ian Thompson
We consider a plane flexural wave incident on a semi-infinite rigid strip in a Mindlin plate. The boundary conditions on the strip lead to three Wiener–Hopf equations, one of which decouples, leaving a scalar problem and a 2 × 2 matrix problem. The latter is solved using a simple method based on quadrature. The far-field diffraction coefficient is calculated and some numerical results are presented
-
On the accuracy and applicability of a new implicit Taylor method and the high-order spectral method on steady nonlinear waves Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Mathias Klahn; Per A. Madsen; David R. Fuhrman
This paper presents an investigation and discussion of the accuracy and applicability of an implicit Taylor (IT) method versus the classical higher-order spectral (HOS) method when used to simulate two-dimensional regular waves. This comparison is relevant, because the HOS method is in fact an explicit perturbation solution of the IT formulation. First, we consider the Dirichlet–Neumann problem of
-
Mixed-precision iterative refinement using tensor cores on GPUs to accelerate solution of linear systems Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Azzam Haidar; Harun Bayraktar; Stanimire Tomov; Jack Dongarra; Nicholas J. Higham
Double-precision floating-point arithmetic (FP64) has been the de facto standard for engineering and scientific simulations for several decades. Problem complexity and the sheer volume of data coming from various instruments and sensors motivate researchers to mix and match various approaches to optimize compute resources, including different levels of floating-point precision. In recent years, machine
-
A fundamental class of stress elements in lower bound limit analysis Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Athanasios Makrodimopoulos
There is a major restriction in the formulation of rigorous lower bound limit analysis by means of the finite-element method. Once the stress field has been discretized, the yield criterion and the equilibrium conditions must be applied at a finite number of points so that they are satisfied everywhere throughout the discretized structure. Until now, only the linear stress elements fulfil this requirement
-
On relativistic gasdynamics: invariance under a class of reciprocal-type transformations and integrable Heisenberg spin connections Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 C. Rogers; T. Ruggeri; W. K. Schief
A classical system of conservation laws descriptive of relativistic gasdynamics is examined. In the two-dimensional stationary case, the system is shown to be invariant under a novel multi-parameter class of reciprocal transformations. The class of invariant transformations originally obtained by Bateman in non-relativistic gasdynamics in connection with lift and drag phenomena is retrieved as a reduction
-
Shearlets as feature extractor for semantic edge detection: the model-based and data-driven realm Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Hctor Andrade-Loarca; Gitta Kutyniok; Ozan ktem
Semantic edge detection has recently gained a lot of attention as an image-processing task, mainly because of its wide range of real-world applications. This is based on the fact that edges in images contain most of the semantic information. Semantic edge detection involves two tasks, namely pure edge detection and edge classification. Those are in fact fundamentally distinct in terms of the level
-
Analytic and numerical solutions to the seismic wave equation in continuous media Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 S. J. Walters; L. K. Forbes; A. M. Reading
This paper presents two approaches to mathematical modelling of a synthetic seismic pulse, and a comparison between them. First, a new analytical model is developed in two-dimensional Cartesian coordinates. Combined with an initial condition of sufficient symmetry, this provides a valuable check for the validity of the numerical method that follows. A particular initial condition is found which allows
-
Bayesian differential programming for robust systems identification under uncertainty Proc. Royal Soc. A: Math. Phys. Eng. Sci. (IF 2.741) Pub Date : 2020-11-25 Yibo Yang; Mohamed Aziz Bhouri; Paris Perdikaris
This paper presents a machine learning framework for Bayesian systems identification from noisy, sparse and irregular observations of nonlinear dynamical systems. The proposed method takes advantage of recent developments in differentiable programming to propagate gradient information through ordinary differential equation solvers and perform Bayesian inference with respect to unknown model parameters