12,689 research outputs found
A 3D Printed Toolbox for Opto-Mechanical Components
Nowadays is very common to find headlines in the media where it is stated
that 3D printing is a technology called to change our lives in the near future.
For many authors, we are living in times of a third industrial revolution.
Howerver, we are currently in a stage of development where the use of 3D
printing is advantageous over other manufacturing technologies only in rare
scenarios. Fortunately, scientific research is one of them. Here we present the
development of a set of opto-mechanical components that can be built easily
using a 3D printer based on Fused Filament Fabrication (FFF) and parts that can
be found on any hardware store. The components of the set presented here are
highly customizable, low-cost, require a short time to be fabricated and offer
a performance that compares favorably with respect to low-end commercial
alternatives.Comment: 9 pages, 9 figure
Phase transition in a super superspin glass
We here confirm the occurrence of spin glass phase transition and extract
estimates of associated critical exponents of a highly monodisperse and densely
compacted system of bare maghemite nanoparticles. This system has earlier been
found to behave like an archetypal spin glass, with e.g. a sharp transition
from paramagnetic to non-equilibrium behavior, suggesting that this system
undergoes a spin-glass phase transition at a relatively high temperature,
140 K.Comment: 4 pages, 3 figure
Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics
The first regular exact black hole solution in General Relativity is
presented. The source is a nonlinear electrodynamic field satisfying the weak
energy condition, which in the limit of weak field becomes the Maxwell field.
The solution corresponds to a charged black hole with |q| \leq 2 s_c m \approx
0.6 m, having the metric, the curvature invariants, and the electric field
regular everywhere.Comment: 5 pages, RevTex, 6 figure
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