Localized states in the conserved Swift-Hohenberg equation with cubic nonlinearity

The conserved Swift-Hohenberg equation with cubic nonlinearity provides the simplest microscopic description of the thermodynamic transition from a fluid state to a crystalline state. The resulting phase field crystal model describes a variety of spatially localized structures, in addition to different spatially extended periodic structures. The location of these structures in the temperature versus mean order parameter plane is determined using a combination of numerical continuation in one dimension and direct numerical simulation in two and three dimensions. Localized states are found in the region of thermodynamic coexistence between the homogeneous and structured phases, and may lie outside of the binodal for these states. The results are related to the phenomenon of slanted snaking but take the form of standard homoclinic snaking when the mean order parameter is plotted as a function of the chemical potential, and are expected to carry over to related models with a conserved order parameter.Comment: 40 pages, 13 figure

Online Estimation of Dynamic Capacity of VSC-HVdc Systems –Power System Use Cases

The dynamic capacity describes the capability of high voltage direct current (HVdc) systems to operate temporarily beyond their guaranteed active and reactive power (P/Q) limitations under specific conditions. In this work, the dynamic capacity is intended to be applied in various power system use cases to ensure a more efficient and secure grid operation. In contrast to previous works, the dynamic capacity is considered with a holistic view on the HVdc system’s components. Moreover, to overcome existing limitations considering only the HVdc system design, it is introduced to estimate the dynamic capacity based on real-time operational data. In principle, dynamic capacity could help for any power system use case where temporarily additional capacity is required. The article details five use cases, including congestion management, voltage support, frequency response, offshore wind overplanting and grid planning to be of high interest for such a feature. The main HVdc applications, embedded systems, interconnectors and offshore grid connection, and anticipated time frames for dynamic capacity are highlighted from power system perspective. Also, the time-criticality of the remedial actions is outlined

Dynamical density functional theory for the dewetting of evaporating thin films of nanoparticle suspensions exhibiting pattern formation

Recent experiments have shown that the striking structure formation in dewetting films of evaporating colloidal nanoparticle suspensions occurs in an ultrathin “postcursor” layer that is left behind by a mesoscopic dewetting front. Various phase change and transport processes occur in the postcursor layer that may lead to nanoparticle deposits in the form of labyrinthine, network, or strongly branched “finger” structures. We develop a versatile dynamical density functional theory to model this system which captures all these structures and may be employed to investigate the influence of evaporation or condensation, nanoparticle transport, and solute transport in a differentiated way. We highlight, in particular, the influence of the subtle interplay of decomposition in the layer and contact line motion on the observed particle-induced transverse instability of the dewetting front

Modeling the structure of liquids and crystals using one- and two-component modified phase-field crystal models

A modified phase-field crystal model in which the free energy may be minimized by an order parameter profile having isolated bumps is investigated. The phase diagram is calculated in one and two dimensions and we locate the regions where modulated and uniform phases are formed and also regions where localized states are formed. We investigate the effectiveness of the phase-field crystal model for describing fluids and crystals with defects.We further consider a two-component model and elucidate how the structure transforms from hexagonal crystalline ordering to square ordering as the concentration changes. Our conclusion contains a discussion of possible interpretations of the order parameter field

The effects of self-efficacy, perceptions of ethical misconduct, and guilt-proneness on CWBs

This study examined the relationship between generalized self-efficacy, perceptions of ethical misconduct, guilt-proneness, and counterproductive work behaviors. We first hypothesized that self-efficacy would be negatively related to counterproductive work behaviors. Secondly, we hypothesized that perceptions of ethical misconduct and levels of guilt-proneness would mediate the negative relationship between generalized self-efficacy and counterproductive work behaviors. We surveyed 190 undergraduate students. To test our hypotheses, we used serial mediation (self-efficacy perceptions of ethical misconduct Guilt CWBs). Results supported our first hypothesis. However, we did not find support for the mediated relationship proposed in our second hypothesis

Employee characteristics: resilience and self-efficacy as protective factors

This study will explore the relationship between self-efficacy and resilience as they affect stress-related outcomes in the workplace. The study will first measure all participant’s self-efficacy and resilience. The experimental group will then receive feedback mirroring that of a negative performance appraisal. The feedback will suggest the participant performed below average on a trivia test. Participants in the control group will receive neutral feedback on the same trivia test. Lastly, all participant’s resilience will be measured a second time. This study will seek to recruit students from a local South-Eastern university. The results of this study will further clarify the relationship that exists between self-efficacy and resilience as well as further demonstrating the value of resilience as a protective factor

On the Modeling of Bearing Voltage and Current in PWM Converter-Fed Electric Machines Using Electromagnetic Finite Element Analysis

Bearing voltages and resulting currents in electric machines driven by PWM converters with fast switching and high dv/dt can cause premature bearing failures. With the transition from conventional Si devices to wide bandgap (WBG) devices and increase in switching frequency, bearing voltages and currents become more significant and need to be addressed from the early design stage. This paper proposes to use coupled field-circuit electromagnetic finite element analysis (FEA) to model bearing voltage and current in electric machines, which takes into account the influence of distributed winding conductors and frequency-dependent winding RL parameters. The three known bearing current types are explained and modeled in a unified way by using the proposed approach with simple calculation examples. Potential bearing current issues in axial-flux machines, and possibilities of computation time reduction, are also discussed

Single atom trapping in a metasurface lens optical tweezer

Optical metasurfaces of sub-wavelength pillars have provided new capabilities for the versatile definition of the amplitude, phase, and polarization of light. In this work we demonstrate that an efficient dielectric metasurface lens can be used to trap and image single neutral atoms. We characterize the high numerical aperture optical tweezers using the trapped atoms and compare to numerical computations of the metasurface lens performance. We predict future metasurfaces for atom trapping can leverage multiple ongoing developments in metasurface design and enable multifunctional control in complex experiments with neutral-atoms arrays.Comment: 9 pages, 5 figure