16,221 research outputs found
Solitonic Phase in Manganites
Whenever a symmetry in the ground state of a system is broken, topological
defects will exist. These defects are essential for understanding phase
transitions in low dimensional systems[1]. Excitingly in some unique condensed
matter systems the defects are also the low energy electric charge excitations.
This is the case of skyrmions in quantum Hall ferromagnets[2] and solitons in
polymers[3]. Orbital order present in several transitions metal compounds[4-6]
could give rise to topological defects. Here we argue that the topological
defects in orbital ordered half doped manganites are orbital solitons.
Surprisingly, these solitons carry a fractional charge of e/2, and
whenever extra charge is added to the system an array of solitons is formed and
an incommensurate solitonic phase occurs. The striking experimental asymmetry
in the phase diagram as electrons or holes are added to half doped
manganites[7-12], is explained by the energy difference between positive and
negative charged solitons. Contrary to existent models that explain coexistence
between phases in manganites as an extrinsic effect[13-14], the presence of
inhomogeneities is naturally explained by the existence of solitonic phases.
The occurrence and relevance of orbital solitons might be a general phenomena
in strongly correlated systems.Comment: 10 pages, 5 figures include
Gainsharing and Mutual Monitoring: A Combined Agency-Procedural Justice Interpretation
This study examines the behavioral consequences of gainsharing using a combined theoretical framework that includes elements of agency and procedural justice theory. The hypothesis tested is that gainsharing as a collective form of incentive alignment results in increased mutual monitoring among agents (employees) when the plan is perceived to be procedurally fair. The hypothesis was supported in two separate firms using a quasi-experimental field study. The implications of the study for future extensions of agency theory to examine intraorganizational phenomena are discussed
An extended solution space for Chern-Simons gravity: the slowly rotating Kerr black hole
In the Einstein-Cartan formulation, an iterative procedure to find solutions
in non-dynamical Chern-Simons (CS) gravity in vacuum is proposed. The
iterations, in powers of a small parameter which codifies the CS
coupling, start from an arbitrary torsionless solution of Einstein equations.
With Schwarzschild as the zeroth-order choice, we derive a second-order
differential equation for the corrections to the metric,
for an arbitrary zeroth-order embedding parameter. In particular, the slowly
rotating Kerr metric is an solution in either the
canonical or the axial embeddings.Comment: 5 pages, PRD accepte
Flow Blurring-Enabled Production of Polymer Filaments from Poly(ethylene oxide) Solutions
Flow blurring (FB) atomizers are relatively
simple yet robust devices used for the generation of sprays
from solutions of a wide range of viscosities. In this work, we
have demonstrated that FB devices may also be applied for
massive production of liquid filaments from polymeric
solutions. They can later be transformed into solid filaments
and fibers, leading to the production of so-called fiber mats.
The liquid precursors consisted of poly(ethylene oxide)
(PEO) solutions of varying molecular weights (105 [100k]
to 4 × 106 g/mol [4M]) and concentrations. The FB device
was operated in the gas pressure range of 3−6 bar. Except for
solutions of PEO 100k, all solutions exhibited a shear thinning
behavior. For massive filament production, a threshold
polymer concentration (ct) was identified for each molecular
weight. Below such concentration, the atomization resulted in droplets (the classical FB functioning mode). Such a threshold
value decreased as the PEO molecular weight increased, and it coincides with the polymer coil overlap concentration, c*. The
viscoelastic nature of the solutions was also observed to increase with the molecular weight. A 3.2 dependency of the zero-shear
rate viscosity on a so-called Bueche parameter was found for filament production, whereas a nearly linear dependency was found
for droplet production. In general, the mean diameter of the filaments decreased as they traveled downstream from the
atomization point. Furthermore, at a given distance from the atomizer outlet and gas pressure, the mean filament diameter
slightly shifted toward larger sizes with increasing PEO molecular weight. The tendency agrees well with the calculated
filaments’ Deborah number, which increases with PEO molecular weight. The approach presented herein describes a highthroughput
and efficient method for the massive production of viscous filaments. These may be transformed into fibers by an
on-line drying step.Ministerio de Economía y Competitividad DPI2016-78887-C3-1-
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