Potential Boundary Conditions Research Articles

The impact of boundary conditions on calculated photovoltages and photocurrents at photocatalytic interfaces

Abstract

More is less: Learning but not relaxing buffers deviance under job stressors.

Workplace deviance harms the well-being of an organization and its members. Unfortunately, theory and prior research suggest that deviance is associated with job stressors, which are endemic to work organizations and often cannot be easily eliminated. To address this conundrum, we explore actions individuals can take at work that serve as buffering conditions for the positive relationship between job stressors and deviant behavior. Drawing upon conservation of resources theory, we examine a resource-building activity (i.e., learning something new at work) and a demand-shielding activity (i.e., taking time for relaxation at work) as potential boundary conditions. In 2 studies with employee samples using complementary designs, we find support for the buffering role of learning but not for relaxation. When employees learn new things at work, the relationship between hindrance stressors and deviance is weaker; as is the indirect relationship mediated by negative emotions. Taking time for relaxation at work did not show a moderating role in either study. Therefore, although relaxation is a response that individuals might be inclined to turn to for counteracting work stress, our findings suggest that, when it comes to addressing negative emotions and deviance in stressful work environments, building positive resources by learning something new at work could be more useful. In that way, doing more (i.e., learning, and not relaxing) is associated with less (deviance) in the face of job stressors. (PsycINFO Database Record

Electrostatic interactions between charged dielectric particles in an electrolyte solution: constant potential boundary conditions.

The problem of electrostatic interactions between colloidal particles in an electrolyte solution has been solved within the Debye-Hückel approximation using the boundary condition of constant potential. The model has been validated in two independent ways - by considering the limiting cases obtained from DLVO theory and comparison with the available experimental data. The presented methodology provides the final part of a complete theory of pairwise electrostatic interactions between spherical colloidal particles; one that embraces all possible chemical scenarios within the boundary conditions of constant potential and constant charge.

Analysis of the Mean Field Free Energy Functional of Electrolyte Solution with Nonhomogenous Boundary Conditions and the Generalized PB/PNP Equations with Inhomogeneous Dielectric Permittivity

The energy functional, the governing partial differential equation(s) (PDE), and the boundary conditions need to be consistent with each other in a modeling system. In electrolyte solution study, people usually use a free energy form of an infinite domain system (with vanishing potential boundary condition) and the derived PDE(s) for analysis and computing. However, in many real systems and/or numerical computing, the objective domain is bounded, and people still use the similar energy form, PDE(s), but with different boundary conditions, which may cause inconsistency. In this work, (1) we present a mean field free energy functional for the electrolyte solution within a bounded domain with either physical or numerically required artificial boundary. Apart from the conventional energy components (electrostatic potential energy, ideal gas entropy term, and chemical potential term), new boundary interaction terms are added for both Neumann and Dirichlet boundary conditions. These new terms count for physical...

Resonant Robin problems with indefinite and unbounded potential

AbstractWe consider semilinear elliptic problems with an indefinite and unbounded potential and Robin boundary condition. We prove existence and multiplicity theorems when resonance occurs with respect to the principal eigenvalue both from the left and from the right. We also investigate the case where we have resonance with respect to any nonprincipal eigenvalue and prove a multiplicity theorem under general conditions on the reaction term . Our approach uses variational methods, together with truncation and perturbation techniques and Morse theory.

Making connections among multiple visual representations: how do sense-making skills and perceptual fluency relate to learning of chemistry knowledge?

To learn content knowledge in science, technology, engineering, and math domains, students need to make connections among visual representations. This article considers two kinds of connection-making skills: (1) sense-making skills that allow students to verbally explain mappings among representations and (2) perceptual fluency in connection making that allows students to fast and effortlessly use perceptual features to make connections among representations. These different connection-making skills are acquired via different types of learning processes. Therefore, they require different types of instructional support: sense-making activities and fluency-building activities. Because separate lines of research have focused either on sense-making skills or on perceptual fluency, we know little about how these connection-making skills interact when students learn domain knowledge. This article describes two experiments that address this question in the context of undergraduate chemistry learning. In Experiment 1, 95 students were randomly assigned to four conditions that varied whether or not students received sense-making activities and fluency-building activities. In Experiment 2, 101 students were randomly assigned to five conditions that varied whether or not and in which sequence students received sense-making and fluency-building activities. Results show advantages for sense-making and fluency-building activities compared to the control condition only for students with high prior chemistry knowledge. These findings provide new insights into potential boundary conditions for the effectiveness of different types of instructional activities that support students in making connections among multiple visual representations.

NK model as a representation of innovative search

The process of innovation is frequently modeled as a bounded, iterative, trial-and-error search over a complex landscape using an NK model. An important question, however, is whether such theoretical approximation is consistent with empirical data. Prior work tested specific insights of the NK model while yielding mixed evidence. I examine how the full set of predictions generated by the NK model map onto observed empirical patterns while relying on commonly used patent-based measures of complexity. While the fit between the predictions and data is not perfect, I find that the ability of the NK model to capture innovative processes is better than previously thought. While doing so, I draw attention to potential boundary conditions for both the applicability of the model and usefulness of the measures. The study sheds new light on an important discussion within the field of innovation and technology management and helps to bridge the gap between the NK model and its empirical implementation.

Nonhomogeneous Hemivariational Inequalities with Indefinite Potential and Robin Boundary Condition

We consider a nonlinear, nonhomogeneous Robin problem with an indefinite potential and a nonsmooth primitive in the reaction term. In fact, the right-hand side of the problem (reaction term) is the Clarke subdifferential of a locally Lipschitz integrand. We assume that asymptotically this term is resonant with respect the principal eigenvalue (from the left). We prove the existence of three nontrivial smooth solutions, two of constant sign and the third nodal. We also show the existence of extremal constant sign solutions. The tools come from nonsmooth critical point theory and from global optimization (direct method).

Evaluating the heat-aggression hypothesis: The role of temporal and social factors in predicting baseball related aggression.

We examined the role that season progression and social threats play in the heat-aggression hypothesis within Major League Baseball put forward by Reifman, Larrick, and Fein (1991). Box score data from 38,870 Major League Baseball games between the years of 2000 and 2015 was used to test the heat-aggression relationship, while accounting for temporal and social factors that may be simultaneously exerting influence on player behavior. Controlling for a number of other variables, we observed that the effect of temperature on aggressive behavior is partially contingent on the point of the season in which the game took place. Aggressive behavior was also more likely to occur when teams played divisional (compared to league and inter-league) rivals, however this relationship was contingent on season progression. We provide potential boundary conditions relating to the heat-aggression relationship, indicating this may not be a ubiquitous phenomenon.

Nano- and Mesoscale Ion and Water Transport in Perfluorosulfonic-Acid Membranes

High performance of polymer-electrolyte fuel cells requires rapid cation conduction through perflurosulfonic-acid (PFSA) membranes. Consequently, understanding water and aqueous cation transport in aqueous nanoscale domains (nano length scale) and connectivity and tortuosity of the microscale domains (meso length scales) is critical to optimizing PFSA membrane design. Due to transport coupling, membrane ionic conduction depends not only on electrostatic potential gradients but also on water content gradients (i.e. electro-osmosis). In this work, we model coupled cation and water transport in PFSA membranes at the nano- and mesoscale and predict macroscopic properties. We adopt a mean-field local-density theory for cation and water chemical potentials to predict transport in the nanoscale PFSA aqueous domains. Cation-polymer electrostatic interactions and solvation energy are included. Concentrated solution transport theory (Stefan-Maxwell formulation) models diffusion and specifically accounts for dielectric friction induced by the strong electrostatic fields of charged polymer groups. To model the mesoscale, a resistor network that includes Stefan-Maxwell coupling quantifies transport along the segments of the collection of aqueous domains in PFSA membranes. The nanoscale model parameterizes the properties of each segment of the resistor network. With this methodology, we decouple the influences of nano- and mesoscale resistances on macroscopic water and cation transport and electro-osmosis. At the nanoscale there is coupling between water and cation transport from both diffusional drag and electrostatic-driven convection. Electrostatic and pressure forces on the membrane are countered by immobilization of the polymer matrix. The models show the nature of electro-osmosis depends on water content and the vapor and electrostatic potential boundary conditions of the membrane. This work provides a compelling approach to elucidate the multiscale resistances to water and cation transport in PFSA membranes.

Predicting developmental toxicity: Fishing with ‘Omics technology

The process of innovation is frequently modeled as a bounded, iterative, trial-and-error search over a complex landscape using an NK model. An important question, however, is whether such theoretical approximation is consistent with empirical data. Prior work tested specific insights of the NK model while yielding mixed evidence. I examine how the full set of predictions generated by the NK model map onto observed empirical patterns while relying on commonly used patent-based measures of complexity. While the fit between the predictions and data is not perfect, I find that the ability of the NK model to capture innovative processes is better than previously thought. While doing so, I draw attention to potential boundary conditions for both the applicability of the model and usefulness of the measures. The study sheds new light on an important discussion within the field of innovation and technology management and helps to bridge the gap between the NK model and its empirical implementation.

Empowering leadership: A meta‐analytic examination of incremental contribution, mediation, and moderation

SummaryThe concept of empowering leadership (EL) has seen increasing scholarly interest in recent years. This study reports a meta‐analysis investigating the effects of EL on employee work behavior. On the basis of data from 105 samples, we found evidence for the positive effects of EL on performance, organizational citizenship behavior, and creativity at both the individual and team levels. We further examined these relationships by exploring potential boundary conditions and the incremental contribution of EL over transformational leadership and leader–member exchange. Furthermore, at the individual level, both trust in leader and psychological empowerment mediated the relationships of EL with task performance, organizational citizenship behavior, and creativity. We also found evidence that leader–member exchange was a significant mediator between EL and task performance. At the team level, empowerment mediated the effects of EL on team performance, whereas knowledge sharing showed no significant indirect effect. Our results have important theoretical and practical implications and suggest some areas that require further research.

FDI Decisions of Chinese Privately-owned Firms: An Institutional Escapism Perspective

Home country governments influence outward foreign direct investment (OFDI) from emerging economies, but how? Governments can intervene actively and deliberately to support OFDI, but firms can also be driven to make OFDI in order to escape from the institutional constraints that result from government intervention. To address this debate on mechanisms, we leverage the difference between privately owned enterprises (POEs) and state-owned enterprises (SOEs) in China. POEs face strong domestic institutional discrimination, while SOEs are favored during times of institutional reform. We show that POEs perceive greater institutional discrimination in provinces with high levels of government intervention, leading to a greater propensity for OFDI. Furthermore, the effect of this perceived discrimination on OFDI is stronger when POEs have greater firm- specific assets, but formal political connections weaken the effect. These results illustrate how theories about the effect of domestic institutional environments on OFDI are conditional upon features such as the types of firms embedded in these institutional environments, among other potential boundary conditions.

Reconciling Identity Contradiction when Transitioning from Work to Retirement: A Theoretical Model

In an aging society, dealing with the absence of an occupational identity and the quality of retirement adjustment become major concerns for individuals, organizations, and governments. However, the processes through which retirement adjustment can be achieved and upon which conditions this depends are only partially understood. We propose that identity transition contradiction and the number of high quality exchange relationships represent key factors in explaining the diversity in retirement adjustment quality. Integrating identity and social relational perspectives, we develop and elaborate ten propositions to introduce a theoretical model that addresses the process of identity contradiction reconciliation during the work-to-retirement transition. We also discuss the potential boundary conditions of the model, outline directions for future research, and suggest practical implications for management and career counseling.

Towards an understanding of when non-climate frames can generate public support for climate change policy

There is a growing tendency for policy makers to frame climate change action in terms of non-climate benefits, raising important empirical questions regarding the utility of such approaches. Across three studies we explore whether (and when) non-climate frames can lead to greater support for climate policy relative to climate frames. In Study 1 we framed a car-use reduction policy in relation to climate change or public health and showed that non-climate frames can stimulate greater support for climate policy. Study 2 explored frame relevance as a potential boundary condition to the efficacy of non-climate frames. Study 3 found that attempts to frame climate policy in relation to non-climate issues that affect participants personally can fail if that issue is not seen as being sufficiently relevant. We suggest that non-climate frames can be an effective tool in stimulating support for climate policy, however greater consideration of the key mechanisms is required.

Consistent Belief in a Good True Self in Misanthropes and Three Interdependent Cultures.

People sometimes explain behavior by appealing to an essentialist concept of the self, often referred to as the true self. Existing studies suggest that people tend to believe that the true self is morally virtuous; that is deep inside, every person is motivated to behave in morally good ways. Is this belief particular to individuals with optimistic beliefs or people from Western cultures, or does it reflect a widely held cognitive bias in how people understand the self? To address this question, we tested the good true self theory against two potential boundary conditions that are known to elicit different beliefs about the self as a whole. Study 1 tested whether individual differences in misanthropy-the tendency to view humans negatively-predict beliefs about the good true self in an American sample. The results indicate a consistent belief in a good true self, even among individuals who have an explicitly pessimistic view of others. Study 2 compared true self-attributions across cultural groups, by comparing samples from an independent country (USA) and a diverse set of interdependent countries (Russia, Singapore, and Colombia). Results indicated that the direction and magnitude of the effect are comparable across all groups we tested. The belief in a good true self appears robust across groups varying in cultural orientation or misanthropy, suggesting a consistent psychological tendency to view the true self as morally good.

The optimum cut-off radius in Monte Carlo simulation of Yukawa potential point particles

In this paper, infinite systems of point particles with Yukawa potential and periodic boundary conditions are simulated using Monte Carlo technique in three dimensions. Because of the short range nature of the Yukawa potential, cut-off radius rcut is considered in calculations (i.e, for each particle i, the effect of the other particles on it inside a sphere of radius rcut is taken into account). The cut-off radius used in Monte Carlo simulation affects the physical behavior of the system being simulated. A sequence of rcut values are used. When the change in the total potential energy becomes negligible, the optimum value of the cut-off radius is determined. This value is found to be independent of density and temperature in the NVT-ensemble case.

Hydrodynamic force evaluation in lattice Boltzmann method

The lattice Boltzmann method is a mesoscopic numerical method originating from kinetic theory and the cellular automaton concept. It has been successfully used to simulate complex flows, especially particle suspensions and multiphase flows. In this paper, we review our recent work on fluid-structure interactions and nonideal force evaluations. We introduced the relative velocity into the treatment of fluid-structure interfacial dynamics and proposed a Galilean invariant momentum exchange method. The method is simple, accurate and efficient. It is independent of boundary geometries and only uses the local data, thus it is convenient to implement parallelization and 3D simulations. The numerical simulations are so vastly improved that the force fluctuations are very small and a time average procedure becomes unnecessary. To simulate phase separation and two-phase flow, we directly evaluated the nonideal force based on the free energy and proposed a multiphase flow model. Thermodynamic consistency and Galilean invariance of the model are theoretically satisfied and numerically verified. This model can be easily implemented and cooperated with various equations of state to simulate all kinds of the multiphase systems. Chemical potential is an effective way to drive phase transition or express surface wettability. In the further study, we proposed another multiphase flow model based on chemical potential. It is mathematically equivalent to the previous one, but is more computationally efficient owing to avoiding the calculations of pressure tensor and tensor divergence. Together with the chemical potential boundary condition, the model can effectively simulate wetting phenomena. The numerical results show that the contact angle can be linearly tuned by the surface chemical potential.

Positive solutions for perturbations of the Robin eigenvalue problem plus an indefinite potential

We study perturbations of the eigenvalue problem for the negative Laplacian plus an indefinite and unbounded potential and Robin boundary condition. First we consider the case of a sublinear perturbation and then of a superlinear perturbation. For the first case we show that for $\lambda<\widehat{\lambda}_{1}$ ($\widehat{\lambda}_{1}$ being the principal eigenvalue) there is one positive solution which is unique under additional conditions on the perturbation term. For $\lambda\geq\widehat{\lambda}_{1}$ there are no positive solutions. In the superlinear case, for $\lambda<\widehat{\lambda}_{1}$ we have at least two positive solutions and for $\lambda\geq\widehat{\lambda}_{1}$ there are no positive solutions. For both cases we establish the existence of a minimal positive solution $\bar{u}_{\lambda}$ and we investigate the properties of the map $\lambda\mapsto\bar{u}_{\lambda}$.

Heteroaggregation of oppositely charged particles in the presence of multivalent ions.

Time-resolved dynamic light scattering is used to measure absolute heteroaggregation rate coefficients and the corresponding stability ratios for heteroaggregation between amidine and sulfate latex particles. These measurements are complemented by the respective quantities for the homoaggregation of the two systems and electrophoresis. Based on the latter measurements, the stability ratios are calculated using Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. In monovalent salt solutions, the two types of particles investigated are oppositely charged. In the presence of multivalent ions, however, one particle type reverses its charge, while the charge of the other particle type is hardly affected. In this region, the heteroaggregation stability ratio goes through a pronounced maximum when plotted versus concentration. This region of slow aggregation is wider than the one observed in the corresponding homoaggregation process. One also finds that the onset of this region sensitively depends on the boundary conditions used to calculate the double layer force. The present results are more in line with constant potential boundary conditions.