14,478 research outputs found
Two-state shear diagrams for complex fluids in shear flow
The possible "phase diagrams'' for shear-induced phase transitions between two phases are collected. We consider shear-thickening and shear-thinning fluids, under conditions of both common strain rate and common stress in the two phases, and present the four fundamental shear stress vs. strain rate curves and discuss their concentration dependence. We outline how to construct more complicated phase diagrams, discuss in which class various experimental systems fall, and sketch how to reconstruct the phase diagrams from rheological measurements
Overcoming losses with gain in a negative refractive index metamaterial
On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we
investigate the possibility of using gain to overcome losses in a negative
refractive index fishnet metamaterial. We show that appropriate placing of
optically pumped laser dyes (gain) into the metamaterial structure results in a
frequency band where the nonbianisotropic metamaterial becomes amplifying. In
that region both the real and the imaginary part of the effective refractive
index become simultaneously negative and the figure of merit diverges at two
distinct frequency points.Comment: 4 pages, 4 figure
JPL preferred parts list: Reliable electronic components
The JPL Preferred Parts List was prepared to provide a basis for selection of electronic parts for JPL spacecraft programs. Supporting tests for the listed parts were designed to comply with specific spacecraft environmental requirements. The list tabulates the electronic, magnetic, and electromechanical parts applicable to all JPL electronic equipment wherein reliability is a major concern. The parts listed are revelant to equipment supplied by subcontractors as well as fabricated at the laboratory
Democratic Spaces: How Teachers Establish and Sustain Democracy and Education in Their Classrooms
Democratic education focuses on developing students using democratic principles and processes in the classroom. In this study, we aim to understand how self-identified democratic educators practice democratic education in public-school classrooms. Nine participants, teachers in K12 schools, were interviewed for this qualitative study. In investigating how public-school teachers implemented and sustained democratic education in their classrooms, six themes emerged—fostering relationships, empowering students, and teaching and using democratic skills, democratic educative structure, democratic teacher praxis, and obstacles
Twenty Years in the Trenches: A Fight for Equitable and Adequate School Funding in Ohio
Abstract
This single case study examined the perceptions of William L. “Bill” Phillis, the Executive Director of the Ohio Coalition for Equity and Adequacy of School Funding, concerning an unconstitutional funding model, subsequent sociopolitical barriers, and their impact on students and school districts from underprivileged socioeconomic background within the context of the DeRolph v. State of Ohio legal battle. This research adds to the extant literature on the educational implications of the property tax and foundation model of school funding. As well, we discuss William’s insights regarding the politics, nature, and development of the current state of public school financing in Ohio. There were four emergent themes: sociopolitical sentiment and rhetoric, the plight of poorer districts, seeing a shared vision, and constitutional language and responsibility. Key findings from the study provide awareness to foster civic responsibility to effect change for inequitable and inadequate funding formulae, to encourage politicians to abandon political agendas over constitutional will, and for educators and students alike to continually advocate for a reformed system of school funding. These findings are especially relevant among under-resourced districts such as those in Appalachian Ohio.
Key words: advocacy, educational leadership, equity, foundation model, school funding, single-case stud
Low-lying Quasiparticle Excitations around a Vortex Core in Quantum Limit
Focusing on a quantum-limit behavior, we study a single vortex in a clean
s-wave type-II superconductor by self-consistently solving the Bogoliubov-de
Gennes equation. The discrete energy levels of the vortex bound states in the
quantum limit is discussed. The vortex core radius shrinks monotonically up to
an atomic-scale length on lowering the temperature T, and the shrinkage stops
to saturate at a lower T. The pair potential, supercurrent, and local density
of states around the vortex exhibit Friedel-like oscillations. The local
density of states has particle-hole asymmetry induced by the vortex. These are
potentially observed directly by STM.Comment: 4 pages, 6 figure
Multi-order interference is generally nonzero
It is demonstrated that the third-order interference, as obtained from
explicit solutions of Maxwell's equations for realistic models of three-slit
devices, including an idealized version of the three-slit device used in a
recent three-slit experiment with light (U. Sinha et al., Science 329, 418
(2010)), is generally nonzero. The hypothesis that the third-order interference
should be zero is shown to be fatally flawed because it requires dropping the
one-to-one correspondence between the symbols in the mathematical theory and
the different experimental configurations.Comment: Replaced Figs. 4,5 and caption of Fig.
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