Education: PhD in Physics, 1997,
University of Seville.
Doctoral thesis: Static and dynamics
of granular materials Xerographic.
Supervisor:
Antonio Castellanos Mata y Alberto T. Pérez Izquierdo.
Main scientific results:
Development of a powder
test, not only restricted to the diagnosis of fluidity,
but also a powerful instrument for investigating the
physical properties of cohesive fine powders.
The flow of coarse
granular materials is characterized by the transition from
plastic to inertial flow, while the flow of fine particles
at atmospheric pressure is characterized by the transition
from plastic to fluidized flow.
We have developed a
powder test, by which the relationship between effort of
consolidation, tensile strength and free volume of fine
powder, initialized in a reproducible state, is measured.
At low consolidations,
the adhesion force between the plastic particles
micrometer increase linearly with the load force between
particles, indicating the elasto-plastic behavior.
In consolidation
stresses greater than 200 Pa, the strength of adhesion
between the micrometric plastic particles increase
proportionally to the square of the root of the load force
between particles, since it corresponds completely to a
plastic behavior.
Two regimes have been
observed in a non-bubbling fluidised bed of powder Fine:
solid and fluidic.
Local measurements of
the optical probe show the existence of structures
pseudoturbulent mesoscale and short-lived voids in the
fluid regime, reminiscent of beds fluidized by liquid, and
responsible for rapid diffusive transport.
Fine particles aggregate
in DLA fractals aggregated in fluidization due to adhesive
forces between particles that exceed several orders of
magnitude the particle's weight.
The amount of particles
added decreases according to the proportion of force of
attraction between particles for the decreases in the
weight of the particles.
The range of fluidic
behavior in fluidized beds of fine powders decreases as
the number of aggregate particles decreases, and tends to
zero for particles that are neither coagulable nor
aggregated.
The vibration reduces
the amplitude of the range of fluidic behavior promoting
the rupture of aggregates, therefore the aggregation plays
a main role in the prevention of the growth of large
bubbles throughout the extended interval of fluid form.
In the transition from
fluid to solid, the fractal clusters agglomerate in a
metastable state in fractions of volume depending on the
attractive energy and close to the volume fraction of
unattractive hard spheres in jamming.
Near the phase
transition, the stress ratio (solid volume fraction) can
be adjusted to a critical functional form for a small
range of applied stresses, measured in foams, emulsions
and colloidal systems and predicted by numerical
simulations in hard spheres.
Above critical stress,
the volume-stress ratio of the solid volume passes to the
logarithmic law that is typically used to describe the
compaction behavior of soils and characterized by a
compression index parameter.
The increase of the
compression ratio with the proportion of the force of
attraction between particles and the weight of the
particle is consistent with the hypothesis that the
intra-cluster vacuum distribution effectively controls the
compaction process.
In the large limit of
compaction of our fine irregular particles produced by a
wear process reaches a narrow packed package at random
with a fraction of particle volume of about 0.54, which is
similar to that measured for large mechanically crushed
quasimonodisperse grains, such as rocks, of morphology
similar to our fine particles.
Avalanche fine cohesive
powders through internal sliding surfaces depending on the
cohesion of the powder and the boundary conditions, in
contrast to the behavior of non-cohesive grains, such as
dry sand, where the avalanches consist of surface layers
of about ten grains.
In a slowly rotated drum,
avalanche sizes, time interval between avalanches and
maximum stable angle do not follow a SOC behavior, but
scale with powder cohesion.
Avalanches of granular
materials of decreasing particle size in a slowly rotated
drum shows gradual transition from a coherent oscillation
to an irregular long-term correlated behavior reminiscent
of the transitional behavior observed in plasmas and
reproduced by modified models of cellular automata since
the parameter of Fluidization length is increased.
A common observation is
that an attractive interaction between particles improves
the formation of spatio-temporal structures and,
therefore, the memory and collective coherent behavior of
the system.
Main scientific publications:
Authors: Jose Manuel Valverde Millán, Antonio
Castellanos Mata, Antonio Ramos Reyes, Alberto Tomás Pérez
Izquierdo, M.A. Morgan and P. K. Watson.
Authors: Antonio Castellanos Mata, Jose Manuel
Valverde Millán, Alberto Tomás Pérez Izquierdo, Antonio
Ramos Reyes and P.K. Watson.
Authors: Jose Manuel Valverde Millán, Miguel Ángel
Sánchez Quintanilla, and Antonio Castellanos Mata.
Authors: Jose Manuel Valverde Millán, Miguel Ángel
Sánchez Quintanilla, and Antonio Castellanos Mata.
Authors: Jose Manuel Valverde Millán, Miguel Ángel
Sánchez Quintanilla, and Antonio Castellanos Mata.
Patents:
Popularization books:
High Solids Redispersion of Liquid Inks.
Authors: Valverde Millán, Jose Manuel y Castellanos
Mata, Antonio.
Powder Flow: the Shear Fracture of a Tilted Layer of
Xerographic Toner. 1997.
Authors: Ramos Reyes, Antonio; Valverde Millán, Jose
Manuel; Castellanos Mata, Antonio; Watson, P. Keith, Watson,
P. Keith, et. al.
Electromagnetic Waves in Anisotropic Dielectric
Media. University Editor Group. 2007. ISBN
97-8848-491-847-9.
Authors: Valverde Millán, Jose Manuel.
Granular Media Technology. Santander (SPAIN).
Secretariat of Publications of the University of Seville.
2008.
Authors: Valverde Millán, Jose Manuel; Castellanos
Mata, Antonio; Sánchez Quintanilla, Miguel Angel.
Springer Particle Technology Series. Sprin. 2012.
Authors: Valverde Millán, Jose Manuel.
Fluidization of Fine Powders: Cohesive versus
Dynamical Aggregation. Netherlands. Springer. 2013.
Authors: Valverde Millán, Jose Manuel.
Springer Particle Technology Series. Springer. 2012.
ISBN 1567-827X.
Authors: Valverde Millán, Jose Manuel.
Alternating Field Electronanofluidization. Vol.
1145. Pag. 97-100. En: Powders and Grains 2009:
Proceedings of the 6th International Conference on
Micromechanics. The American Institute of Physics. 2009.
ISBN 978-0-7354-0682-7.
Authors: Espín Milla, Manuel Jesús; Valverde Millán,
Jose Manuel; Sánchez Quintanilla, Miguel Angel; Castellanos
Mata, Antonio.
Magnetofluidization of Fine Magnetite Particles.
Vol. 1145. Pag. 119-122. En: Powders and Grains 2009:
Proceedings of the 6th International Conference on
Micromechanics. The American Institute of Physics. 2009.
ISBN 978-0-7354-0682-7.
Authors: Sánchez Quintanilla, Miguel Angel, Espín
Milla, Manuel Jesús; Valverde Millán, Jose Manuel;
Castellanos Mata, Antonio.
Particle Structuring and Yield Stress in
Magnetofluidized Beds. Vol. 1254. Pag. 33-38. En: Porous
Media and Its Applications in Science, Engineering, and
Industry: 3rd International. The American Institute of
Physics. 2010. ISBN 978-0-7354-0803-6.
Authors: Valverde Millán, Jose Manuel; Espín Milla,
Manuel Jesús; Sánchez Quintanilla, Miguel Angel; Castellanos
Mata, Antonio.
PhD supervisor:
Optimization of CO2 capture by fixed and fluidized
beds of calcium-based adsorbents at laboratory scale.
Doctoral Thesis 2016.
Author: Pérez Ebrí, Jose Manuel
For any questions or suggestions contact me through my
email.
