Effect Of Various Distributions Research Articles

Heterogeneous contributions can jeopardize cooperation in the public goods game.

When studying social dilemma games, a crucial question arises regarding the impact of general heterogeneity on cooperation, which has been shown to have positive effects in numerous studies. Here, we demonstrate that heterogeneity in the contribution value for the focal public goods game can jeopardize cooperation. We show that there is an optimal contribution value in the homogeneous case that most benefits cooperation depending on the lattice. In a heterogeneous scenario, where strategy and contribution coevolve, cooperators making contributions higher than the optimal value end up harming those who contribute less. This effect is notably detrimental to cooperation in the square lattice with von Neumann neighborhood, while it can have no impact in other lattices. Furthermore, in parameter regions where a higher-contributing cooperator cannot normally survive alone, the exploitation of lower-value contribution cooperators allows their survival, resembling a parasitic behavior. To obtain these results, we examined the effect of various distributions for the contribution values in the initial condition and we conducted Monte Carlo simulations.

Analysis of wave propagation in functionally graded piezoelectric composite plates reinforced with graphene platelets

This paper presents a semi-analytical approach to investigate wave propagation characteristics in functionally graded graphene reinforced piezoelectric composite plates. Three patterns of graphene platelets (GPLs) describe the layer-wise variation of material properties in the thickness direction. Based on the Reissner-Mindlin plate theory and the isogeometric analysis, elastodynamic wave equation for the piezoelectric composite plate is derived by Hamilton’s principle and parameterized with the non-uniform rational B-splines (NURBS). The equation is transformed into a second-order polynomial eigenvalue problem with regard to wave dispersion. Then, the semi-analytical approach is validated by comparing with the existing results and the convergence on computing dispersion behaviors is also demonstrated. The effects of various distributions, volume fraction, size parameters and piezoelectricity of GPLs as well as different geometry parameters of the composite plate on dispersion characteristics are discussed in detail. The results show great potential of graphene reinforcements in design of smart composite structures and application for structural health monitoring.

Application of nonlocal strain gradient theory to size dependent bending analysis of a sandwich porous nanoplate integrated with piezomagnetic face-sheets

Bending analysis of a sandwich plate is studied in this paper based on first order shear deformation theory and nonlocal strain gradient theory. The sandwich nanoplate is including a porous core and two piezomagnetic facesheets. It is assumed that nanoplate is resting on Pasternak's foundation. Power law function is used to describe change of porosity along the thickness direction. To account size dependency, nonlocal strain gradient theory is employed to predict this behavior. The principle of virtual work is used to derive governing equations in terms of primary functions. A nonlocal parameter and a strain gradient parameter are employed to describe both stiffness reduction and stiffness enhancement of nanoplates. The analytical solution is presented to solve seven governing equation using Navier’s solution. The numerical results are presented to evaluate the effect of various distribution of porosities, porosity volume fraction, nonlocal and strain gradient parameter, electric and magnetic potentials, geometrical characteristics, and parameters of foundation on the results of problem.

Geographically isolated wetlands and watershed hydrology: A modified model analysis

Summary Geographically isolated wetlands (GIWs) are defined as wetlands that are completely surrounded by uplands. While GIWs are therefore spatially isolated, field-based studies have observed a continuum of hydrologic connections between these systems and other surface waters. Yet few studies have quantified the watershed-scale aggregate effects of GIWs on downstream hydrology. Further, existing modeling approaches to evaluate GIW effects at a watershed scale have utilized conceptual or spatially disaggregated wetland representations. Working towards wetland model representations that use spatially explicit approaches may improve current scientific understanding concerning GIW effects on the downstream hydrograph. The objective of this study was to quantify the watershed-scale aggregate effects of GIWs on downstream hydrology while emphasizing a spatially explicit representation of GIWs and GIW connectivity relationships. We constructed a hydrologic model for a ∼202 km2 watershed in the Coastal Plain of North Carolina, USA, a watershed with a substantial population of GIWs, using the Soil and Water Assessment Tool (SWAT). We applied a novel representation of GIWs within the model, facilitated by an alternative hydrologic response unit (HRU) definition and modifications to the SWAT source code that extended the model’s “pothole” representation. We then executed a series of scenarios to assess the downstream hydrologic effect of various distributions of GIWs within the watershed. Results suggest that: (1) GIWs have seasonally dependent effects on baseflow; (2) GIWs mitigate peak flows; and (3) The presence of GIWs on the landscape impacts the watershed water balance. This work demonstrates a means of GIW simulation with improved spatial detail while showing that GIWs, in-aggregate, have a substantial effect on downstream hydrology in the studied watershed.

Combinational effects of various distributions of charcoal and ectomycorrhiza in soil on the growth of Larix gmelinii. seedlings

Combinational effects of various distributions of charcoal and ectomycorrhiza in soil on the growth of Larix gmelinii. seedlings

Breakage and debonding of short brittle fibres among particulates in a metal matrix

Abstract The competition of failure by fibre cracking or decohesion of the fibre-matrix interface is analysed for aluminium reinforced by aligned, short SiC fibres. An axisymmetric unit-cell model containing a number of differently shaped fibres or particulates is used here to represent failure by debonding or fracture of a relatively long discontinuous fibre among particulates that do not fail. A cohesive zone model that accounts for normal separation as well as tangential separation is used to represent debonding, while fibre fracture is represented by a critical value of the average tensile stress on a cross-section. The effect of various distributions of different size fibres is investigated.

Grain-boundary-controlled impedances of electroceramics: Generalized effective-medium approach and brick-layer model

In every electroceramic there exist variations throughout the microstructure of both grain size (and shape) and electrical properties of individual grain boundaries. To calculate the effects of such microstructural variations on the frequency-dependent impedance/dielectric behavior, we describe a generalized statistical effective-medium approach based on effective-medium theory. To illustrate the predictions of the approach, the effect of various distributions in the grain boundary conductivity and the grain size, as well as the grain shape and porosity, are considered. The calculations show that such variations lead to depression of the boundary arc and deviations of the impedance spectra from the well-known brick-layer model with an idealized microstructure consisting of identical grains and grain boundaries.

Temporal Characteristics of NMR Signals from Spin 3/2 Nuclei of Incompletely Disordered Systems

Anisotropic nuclear quadrupole interactions can produce residual quadrupole splitting in the NMR spectra of rapidly moving quadrupolar nuclei in incompletely disordered aqueous heterogeneous systems. Such systems may include hydrated sodium nuclei in biological tissue and biopolymer gels. To describe the NMR signals from such samples, we use a domain model in which each domain is characterized by a quadrupole frequency and a residence time of the nucleus. We show that the signals from each domain after one pulse, the quadrupole echo sequence, and the various multiple quantum filters (MQFs) can be expressed as a linear combination of five different phase coherences. To simulate the effect of various distributions (Pake powder pattern, Gaussian, etc.) of quadrupole frequencies for different domains on the NMR signal, we have written the computer program CORVUS. CORVUS also includes the effects of exchange between different domains using diffusion and random jump models. The results of computer simulations show that the Gaussian and Pake powder pattern quadrupole frequency distributions produce very different phase coherences and observable NMR signals when the exchange rate (1/taue) between different domains is slow. When 1/taue is similar to the root mean square quadrupole frequency (final sigma), the signals from the two distributions are similar. When 1/taue is an order of magnitude greater than final sigma, there is no apparent evidence of quadrupole splitting in the shape of the signal following one pulse, but the residual effects of the quadrupole splitting make a significant contribution to the fast transverse relaxation rate. Therefore, in this case, it is inappropriate to use the observed biexponential relaxation rates to obtain a single correlation time. The quadrupole echo and the various MQF signals contain an echo from the satellite transitions in the presence of quadrupole splitting. The peak of this echo is very sensitive to 1/taue. The time domain analysis of these signals is more direct and less ambiguous than the frequency domain analysis because the echo does not occur at the beginning of data acquisition. The quadrupole echo pulse sequence is the most sensitive detector of residual quadrupole splitting and exchange of sodium ions between different domains. However, if the sample is compartmentalized so that only a fraction of the nuclei have quadrupole splitting, the double quantum magic angle filter (DQ-MA) is more suitable. This is because the DQ-MA signal contains only the contributions from satellite transitions. Use of simulations to analyze signals from various one-pulse, quadrupole echo, and multiple quantum filter pulse sequences can yield information on substrate order and aid in quantitation of multiple quantum filter signals.

Magnetic domains in amorphous metal ribbons (invited)

The results of various static and dynamic studies of domains in amorphous metals by SEM and Bitter techniques are reviewed. Observations include domain widths and orientations, wall mobility and pinning, domain-wall energy measurements, and the effects of various distributions of residual or applied stresses on domain patterns. Domain structures resulting from longitudinal, transverse, and perpendicular anisotropies are contrasted.

Three dimensional temperature and thermoelastic stress fields in a heat producing sphere due to arbitrary surface heat transfer

A method based on a truncated series of spherical harmonics is developed for the solutions of temperature and stress fields due to variable heat transfer over the surface of a sphere with a uniform heat source. The coefficients of the series are obtained by application of the least squares principle to the relevant boundary conditions. The method is applied to a number of heat transfer distributions of practical interest and results are plotted. Conclusions are drawn regarding the effect of various distributions on temperature and stresses and also regarding possible simplified treatment of complex distributions by consideration of the symmetry involved.

Temperature and thermoelastic stress fields in an infinite half-space due to axisymmetric surface heat transfer: Part I. Iterative perturbation solution of integral equation formulation

An iterative perturbation method is developed, based on an integral equation, for the solution of temperature and stress fields due to localised axisymmetric variation of the heat transfer coefficient over the surface of a heat producing infinite half-space. The method is applied to a number of heat transfer distributions of practical interest and results are plotted. Conclusions are drawn regarding the effect of various distributions on the temperatures and stresses.

Temperature and thermoelastic stress fields in a heat producing sphere due to axisymmetric surface heat transfer

An iterative-perturbation series method is developed for solution of temperature and stress fields due to axisymmetric heat transfer coefficient variation over the surface of a heat producing sphere. The method is applied to a number of heat transfer distributions of practical interest and results are plotted. Conclusions are drawn regarding the effect of various distributions and their amplitude variations on the temperatures and stresses.