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1.
Sci Data ; 11(1): 621, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866794

RESUMO

This paper describes a comprehensive energy-related dataset, collected from residential electricity households within an energy community in Ireland, as part of StoreNet project. The data includes local weather parameters and per household power (W) and energy (Wh) components for various aspects such as active power consumption, PV generation, grid import and export, charging and discharging, and the state of charge of energy storage. Additionally, it provides weather data for the location at a 1-minute temporal resolution for the year 2020. The dataset has been validated by comparing measurements that should yield identical results to standard load profiles, with no significant inconsistencies discovered. Validation examples have also been given through the published articles where this dataset has been used to analyse peer-to-peer energy trading benefits for the energy community and decision-making support for aggregators. The dataset aids in understanding patterns in electrical load curves and the duty cycle of energy storage within an energy community. Furthermore, it can assist in comprehending the impact on distribution networks caused by distributed energy storage.

2.
Proc Natl Acad Sci U S A ; 120(23): e2210242120, 2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37256929

RESUMO

Directional solidification of aqueous solutions and slurries in a temperature gradient is widely used to produce cellular materials through a phase separation of solutes or suspended particles between growing ice lamellae. While this process has analogies to the directional solidification of metallurgical alloys, it forms very different hierarchical structures. The resulting honeycomb-like porosity of freeze-cast materials consists of regularly spaced, lamellar cell walls which frequently exhibit unilateral surface features of morphological complexity reminiscent of living forms, all of which are unknown in metallurgical structures. While the strong anisotropy of ice-crystal growth has been hypothesized to play a role in shaping those structures, the mechanism by which they form has remained elusive. By directionally freezing binary water mixtures containing small solutes obeying Fickian diffusion, and phase-field modeling of those experiments, we reveal how those structures form. We show that the flat side of lamellae forms because of slow faceted ice-crystal growth along the c-axis, while weakly anisotropic fast growth in other directions, including the basal plane, is responsible for the unilateral features. Diffusion-controlled morphological primary instabilities on the solid-liquid interface form a cellular structure on the atomically rough side of the lamellae, which template regularly spaced "ridges" while secondary instabilities of this structure are responsible for the more complex features. Collating the results, we obtain a scaling law for the lamellar spacing,  [Formula: see text] , where [Formula: see text] and [Formula: see text] are the local growth rate and temperature gradient, respectively.

3.
Nat Commun ; 14(1): 2244, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37076477

RESUMO

Spatially extended cellular and dendritic array structures forming during solidification processes such as casting, welding, or additive manufacturing are generally polycrystalline. Both the array structure within each grain and the larger scale grain structure determine the performance of many structural alloys. How those two structures coevolve during solidification remains poorly understood. By in situ observations of microgravity alloy solidification experiments onboard the International Space Station, we have discovered that individual cells from one grain can unexpectedly invade a nearby grain of different misorientation, either as a solitary cell or as rows of cells. This invasion process causes grains to interpenetrate each other and hence grain boundaries to adopt highly convoluted shapes. Those observations are reproduced by phase-field simulations further demonstrating that invasion occurs for a wide range of misorientations. Those results fundamentally change the traditional conceptualization of grains as distinct regions embedded in three-dimensional space.

4.
Phys Rev E ; 102(3-1): 032803, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33075956

RESUMO

The oscillatory behavior of cellular patterns produced by directional solidification of a transparent alloy under microgravity conditions was recently observed to depend on the misorientation of the main crystal axis with respect to the direction of the imposed thermal gradient [Pereda et al., Phys. Rev. E 95, 012803 (2017)2470-004510.1103/PhysRevE.95.012803]. To characterize the oscillatory-nonoscillatory transition resulting from the variations of the crystal misorientation, new experiments performed in DECLIC-DSI onboard the International Space Station and phase-field simulations are analyzed and combined in the present study. Experimental results are extracted from movies showing regions that extend on both sides of a boundary between two grains with respective misorientations of roughly 3 and 7 degrees. A set of tools are developed to analyze the experimental data and the same analysis is reproduced for the numerical data. A number of points are addressed in the simulations, like the effects of the system dimensions. The oscillatory state is found to be favored by the increase of the geometrical degrees of freedom. In bulk samples, a good agreement is found between the experimental and the numerical oscillatory-nonoscillatory threshold given by the ratio of the drift time to the oscillation period at the transition. The existence and the origin of bursts of localized groups of oscillating cells within a globally nonoscillatory pattern are characterized. A qualitative description of the physical mechanism that governs the oscillatory-nonoscillatory transition is provided.

5.
Cyberpsychol Behav Soc Netw ; 20(3): 180-186, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28263680

RESUMO

Flow experience has been widely investigated in experiential activities such as sports, the performing arts, gaming, and Internet usage. Most studies focus on the positive aspects of flow experience and its effect on performance. In stark contrast, gambling research focusing on the negative side of addiction lacks an in-depth investigation of gamblers' (positive) flow encounters. This separation of research lines seems out of place given that recent research indicates connections between flow and addiction. Joining both constructs in a causal-effects model helps one gain a better understanding of their relationship and its contingencies. This article empirically investigates whether and how it is possible to observe a "Janus face" of flow with its various sub-dimensions in online gambling. Empirical data were collected from 500 online gamblers by applying a structured questionnaire with established scales. The data were analyzed with a confirmatory factor analysis and a double-hurdle model to separate casual gamblers who are unsusceptible to any addiction issues from gamblers affected by initiatory addiction issues. The findings indicate that online gambling addiction is negatively influenced by two sub-dimensions of flow experience, namely a sense of control and concentration on the task at hand, whereas it is enhanced by a transformation of time and autotelic experience.


Assuntos
Comportamento Aditivo/psicologia , Jogo de Azar/psicologia , Internet/estatística & dados numéricos , Adulto , Comportamento Aditivo/epidemiologia , Feminino , Jogo de Azar/epidemiologia , Humanos , Masculino
6.
Environ Sci Pollut Res Int ; 21(5): 3880-90, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24293301

RESUMO

The concentration of selected heavy metals, like As, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn as well as B, was measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) in groundwater samples from various locations in the Gulf of Khambhat (GoK), an inlet of the Arabian Sea in the state of Gujarat, India, during post-monsoon, winter, and pre-monsoon seasons in a year. Most heavy elements are characterized by low mobility under slightly alkaline and reducing conditions; concentrations in confined aquifers are smaller than the maximum permissible values for drinking water. The temporal changes indicate that a majority of metals is entering the aquifer during monsoon. Principle component analysis of the heavy metal data suggests that Co, Cu, Cd, and Zn are interrelated with each other and derived significantly from anthropogenic route, while input of Pb and Cr may be due to atmospheric deposition in the study area. Both weathering of rocks and anthropogenic input were found to be main sources of elements in the groundwater. The heavy metal levels in groundwaters of the GoK region in comparison with some of the European and Asian sites were higher; however, these metal levels were found to be comparable with few urban sites in the world.


Assuntos
Arsênio/análise , Boro/análise , Água Subterrânea/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/estatística & dados numéricos , Concentração de Íons de Hidrogênio , Índia , Metais/análise , Análise de Componente Principal , Estações do Ano
7.
Phys Rev E Stat Nonlin Soft Matter Phys ; 81(1 Pt 1): 011603, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20365380

RESUMO

We use a quantitative phase-field approach to study directional solidification in various three-dimensional geometries for realistic parameters of a transparent binary alloy. The geometries are designed to study the steady-state growth of spatially extended hexagonal arrays, linear arrays in thin samples, and axisymmetric shapes constrained in a tube. As a basis to address issues of dynamical pattern selection, the phase-field simulations are specifically geared to identify ranges of primary spacings for the formation of the classically observed "fingers" (deep cells) with blunt tips and "needles" with parabolic tips. Three distinct growth regimes are identified that include a low-velocity regime with only fingers forming, a second intermediate-velocity regime characterized by coexistence of fingers and needles that exist on separate branches of steady-state growth solutions for small and large spacings, respectively, and a third high-velocity regime where those two branches merge into a single one. Along the latter, the growth shape changes continuously from fingerlike to needlelike with increasing spacing. These regimes are strongly influenced by crystalline anisotropy with the third regime extending to lower velocity for larger anisotropy. Remarkably, however, steady-state shapes and tip undercoolings are only weakly dependent on the growth geometry. Those results are used to test existing theories of directional finger growth as well as to interpret the hysteretic nature of the cell-to-dendrite transition.

8.
Nat Mater ; 1(3): 157-9, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12618802

RESUMO

The problem of interface pattern selection in nonlinear dissipative systems is critical in many fields of science, occurring in physical, chemical and biological systems. One of the simplest pattern formations is the Saffman-Taylor finger pattern that forms when a viscous fluid is displaced by a less viscous fluid. Such finger-shaped patterns have been observed in distinctly different fields of science (hydrodynamics, combustion and crystal growth) and this has led to a search for a unified concept of pattern formation, as first proposed by the classic work of D'arcy Thomson. Two-dimensional finger-shaped patterns, observed in flame fronts and the ensembled average shape of the diffusion-limited aggregation pattern, have been shown to be similar to Saffman-Taylor finger shapes. Here we present experimental studies that establish that the cell shapes formed during directional solidification of alloys can be described by the form of the Saffman-Taylor finger shape equation when a second phase is present in the intercellular region.


Assuntos
Ligas/química , Cânfora/química , Teste de Materiais/métodos , Nitrilas/química , Dinâmica não Linear , Reologia/métodos , Modelos Teóricos , Sensibilidade e Especificidade , Propriedades de Superfície , Viscosidade
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