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Author Morhell, N.; Pastoriza, H. url  doi
openurl 
  Title Power law fluid viscometry through capillary filling in a closed microchannel Type Journal Article
  Year 2016 Publication Sensors and Actuators B: Chemical Abbreviated Journal  
  Volume 227 Issue Pages 24-28  
  Keywords Microviscometer; Closed channel; Power law fluid; Non-Newtonian viscosity  
  Abstract In this work we analyze the capillary filling dynamics of non-Newtonian fluids that can be modeled with a power law constitutive equation. We solve the Poiseuille equations for an hydrophilic closed channel where capillary pressures drives the fluid in until a rest position given by the barometric pressure is reached. We show that this dynamics can be used to measure both the coefficient k and exponent n, that describes the power law fluid viscosity and we ran tests on Soda Lime Glass microchannels. Using a simple experimental setup with a USB Microscope and a custom image processing software we were able to measure the power law parameters of whole blood, wall varnish and DI water. The exponents were also obtained from the velocity profiles inside the microchannel using a custom μPIV setup matching both results with those measured with a standard Brookfield Rotational Microviscometer.  
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  Series Volume Series Issue Edition  
  ISSN 0925-4005 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial (up) 723  
Permanent link to this record
 

 
Author Facio, J.I.; Betancourth, D.; Cejas Bolecek, N.R.; Jorge, G.A.; Pedrazzini, P.; Correa, V.F.; Cornaglia, P.S.; Vildosola, V.; García D.J. url  doi
openurl 
  Title Lattice specific heat for the RMIn5 (R=Gd, La,Y; M=Co, Rh) compounds: Non-magnetic contribution subtraction Type Journal Article
  Year 2016 Publication Journal of Magnetism and Magnetic Materials Abbreviated Journal J. Magn. Magn. Mater.  
  Volume 407 Issue Pages 406-4011  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial (up) 730  
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Author Salazar Alarcón, L. and Martínez,E. D. and Rodríguez, L. M. and Pastoriza, H. doi  openurl
  Title Topographical and Physicochemical Contrast in Photopatterned SU-8 Films for Microfabrication of Multilayer Structures Type Journal Article
  Year 2016 Publication Advances in Materials Science and Engineering Abbreviated Journal  
  Volume 2016 Issue Pages 5278102  
  Keywords  
  Abstract During SU-8 standard photolithography process, a patterned topography is formed with a characteristic height profile produced by the different shrinkage of the UV exposed and masked regions. We study the change of wettability, film solubility, and topographic modifications on SU-8 films of different thicknesses and show its relevance in the formation of spinning-flow arrays on top layers made from positive photoresists. Also, considerable contrast in film solubility and surface energy as observed from contact angle measurements is produced. Interface diffusion of the photoresists was also observed and followed by Rutherford Back Scattering. We discuss the derivations of the mentioned effects concerning the limitations to multilayered microfabrication processes and possibilities to take advantage of the surface profiles obtained.  
  Address  
  Corporate Author Thesis  
  Publisher Hindawi Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1687-8434 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial (up) 731  
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Author Correa, V.F.; Betancourth, D.; Sereni, J.G.; Caroca-Canales, N.; Geibel, C. url  doi
openurl 
  Title Remarkable magnetostructural coupling around the magnetic transition in CeCo0.85Fe0.15Si Type Journal Article
  Year 2016 Publication Journal of Physics: Condensed Matter Abbreviated Journal J. Phys.: Condens. Matter  
  Volume 28 Issue 34 Pages 346003  
  Keywords magnetostriction, cerium compounds, magnetism  
  Abstract We report a detailed study of the magnetic properties of CeCo0.85Fe0.15Si under high magnetic

fields (up to 16 Tesla) measuring different physical properties such as specific heat, magnetization,

electrical resistivity, thermal expansion and magnetostriction. CeCo0.85Fe0.15Si becomes

antiferromagnetic at TN 6.7 K. However, a broad tail (onset at TX 13 K) in the specific heat

precedes that second order transition. This tail is also observed in the temperature derivative of

the resistivity. However, it is particularly noticeable in the thermal expansion coefficient where it

takes the form of a large bump centered at TX. A high magnetic field practically washes out that tail

in the resistivity. But surprisingly, the bump in the thermal expansion coefficient becomes a well

pronounced peak fully split from the magnetic transition at TN. Concurrently, the magnetoresistance

also switches from negative to positive above TN. The magnetostriction is considerable and

irreversible at low temperature ( (16T)4×10− L

L

4 at 2 K) when the magnetic interactions

dominate. A broad jump in the field dependence of the magnetostriction observed at low T may be

the signature of a weak ongoing metamagnetic transition. Taking altogether the results indicate the

importance of the lattice effects on the development of the magnetic order in these alloys.
 
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  Notes Approved no  
  Call Number BT @ victor.correa @ Serial (up) 732  
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Author Martinez, E.D.; Lohr, J.H.; Sirena, M.; Sanchez, R.D.; Pastoriza, H. url  doi
openurl 
  Title Silver nanowires in poly(methyl methacrylate) as a conductive nanocomposite for microfabrication Type Journal Article
  Year 2016 Publication Flexible and Printed Electronics Abbreviated Journal  
  Volume 1 Issue 3 Pages 035003  
  Keywords  
  Abstract A novel nanocomposite resist is presented based on AgNWs dispersed in poly(methyl methacrylate). It is shown that this nanocomposite resist displays sheet resistances below 10 Ω sq −1 for concentrations of AgNWs higher than ##IMG## [http://ej.iop.org/images/2058-8585/1/3/035003/fpeaa3d4dieqn1.gif] {$4 \% {\rm{wt}}$} and can be used for a wide range of microfabrication techniques. The resist can act as a conductive ink that cures at room temperature, form thin films with low sheet resistances, and be used in fast replication methods derived from soft lithography. Furthermore, it can be applied for nano-scale fabrication via electron beam lithography (EBL) on different substrates, including flexible and insulating materials, providing a straightforward method to avoid charging effects. This, being the first report about a nanocomposite resist based on AgNWs for EBL, describes a simple procedure to account for suspended nanowires, forming bridges, nanocantilevers and more complex nanostructures. A wide range of opportunities opens for the single-step fabrication of electronic components in the nano and micro scale.  
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  Series Volume Series Issue Edition  
  ISSN 2058-8585 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial (up) 733  
Permanent link to this record
 

 
Author Cejas Bolecek, N.R.; Kolton, A.B.; Konczykowski, M.; Pastoriza, H.; Dominguez, D.; Fasano, Y. url  doi
openurl 
  Title Vortex matter freezing in Bi2Sr2CaCu28 samples with a very dense distribution of columnar defects Type Journal Article
  Year 2016 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 93 Issue 5 Pages 054505  
  Keywords  
  Abstract We show that the dynamical freezing of vortex structures nucleated at diluted densities in Bi2Sr2CaCu2O8 samples with a dense distribution of columnar defects, B∼10−2BΦ with BΦ=5kG, results in configurations with liquidlike correlations. We propose a freezing model considering a relaxation dynamics dominated by double-kink excitations driven by the local stresses obtained directly from experimental images. With this model we estimate the relaxation barrier and the freezing temperature. We argue that the low-field frozen vortex structures nucleated in a dense distribution of columnar defects thus correspond to an out-of-equilibrium nonentangled liquid with strongly reduced mobility rather than to a snapshot of a metastable state with divergent activation barriers as, for instance, expected for the Bose-glass phase at equilibrium.  
  Address  
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  Publisher American Physical Society Place of Publication Editor  
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  Notes Approved no  
  Call Number BT @ pedrazp @ 10.1103/PhysRevB.93.054505 Serial (up) 738  
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Author Sereni, J.G; Giovannini, M.; Gomez Berisso, M.; Gastaldo, F. url  doi
openurl 
  Title Competition between ferromagnetism and frustrated antiferromagnetism in quasi 2D Ce 2.15 (Pd 1− x Ag x ) 1.95 In 0.9 alloys Type Journal Article
  Year 2016 Publication Journal of Physics: Condensed Matter Abbreviated Journal J. Phys. : Condens. Matter  
  Volume 28 Issue 47 Pages 475601  
  Keywords  
  Abstract Low temperature thermal and magnetic measurements performed on ferro-magneticl (FM) alloys of composition Ce2.15(Pd1−x Ag x )1.95In0.9 are presented. Pd substitution by Ag depresses ${{T}{\text{C}}}(x)$ from 4.1 K down to 1.1 K for x  =  0.5, which is related to the increase of band electrons, with a critical concentration extrapolated to ${{x}{\text{cr}}}\approx 0.6$ . The ${{T}{\text{C}}}(x)$ decrease is accompanied by a weakening of the magnetization of the FM phase. At high temperature (T  >  30 K) the inverse magnetic susceptibility reveals the presence of robust magnetic moments ($2.56\geqslant ~{{\mu}{\text{eff}}}\geqslant 2.4$ ${{\mu}{\text{B}}}$ ), whereas the low value of the Curie–Weiss temperature ${{\theta}{P}}\approx -10$ K excludes any relevant effect from Kondo screening. The specific heat jump at ${{T}{\text{C}}}(x)$ decreases accordingly, while an anomaly emerges at a fixed temperature ${{T}^{\ast}}\approx 1$ K. This unexpected anomaly does not show any associated sign of magnetism checked by AC-susceptibility measurements. Since the total magnetic entropy (evaluated around $T={{T}{\text{C}}}(x=0)$ ) practically does not change with Ag concentration, the transference of degrees of freedom from the FM component to the non-magnetic T * anomaly is deduced. The origin of this anomaly is attributed to an arising magnetic frustration of the ground state and the consequent entropy bottleneck produced by the divergent increasing of density of excitations at low temperature.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-8984 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial (up) 740  
Permanent link to this record
 

 
Author Perez, M.; Lipovetzky, J.; Sofo Haro, M.; Sidelnik, I.; Blostein, J.J.; Alcalde Bessia, F.; Gomez Berisso, M. url  doi
openurl 
  Title Particle detection and classification using commercial off the shelf CMOS image sensors Type Journal Article
  Year 2016 Publication Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Abbreviated Journal Nucl. Instr. Meth. Phys. Res. A  
  Volume 827 Issue Pages 171-180  
  Keywords Radiation detectors; CMOS image sensors; Alpha Particles; Beta rays; Gamma rays; X-rays; Dosimetry  
  Abstract Abstract

In this paper we analyse the response of two different Commercial Off The shelf CMOS image sensors as particle detectors. Sensors were irradiated using X-ray photons, gamma photons, beta particles and alpha particles from diverse sources. The amount of charge produced by different particles, and the size of the spot registered on the sensor are compared, and analysed by an algorithm to classify them. For a known incident energy spectrum, the employed sensors provide a dose resolution lower than microGray, showing their potentials in radioprotection, area monitoring, or medical applications.
 
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial (up) 741  
Permanent link to this record
 

 
Author Franco, D.G.; Sarmiento-Chavez, A.; Schenone, N.; Allcca, A.E.L.; Berisso, M.G.; Fasano, Y.; Guimpel, J. url  doi
openurl 
  Title Characterization of the Nb-B Superlattice System Type Journal Article
  Year 2016 Publication Physica C: Superconductivity and its Applications Abbreviated Journal  
  Volume 531 Issue Pages 93-97  
  Keywords Superlattice; Superconductivity; Transition Edge Sensors  
  Abstract Abstract

We study the growth, stacking and superconducting properties of Nb and B thin films and superlattices. The interest in these resides in their possible use in transition edge neutron sensors. The samples were grown by magnetron sputtering over Si (100) substrates. The X-ray diffraction patterns for all Nb containing samples show a Nb (110) preferential orientation. From the low-angle X-ray reflectivity we obtain information on the superlattice structure. The superconducting transition temperatures of the superlattices, obtained from the temperature dependence of the magnetization, are higher than those of single Nb films of similar thickness. The temperature dependence of the perpendicular and parallel upper critical fields indicate that the superlattices behave as an array of decoupled superconducting Nb layers.
 
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0921-4534 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ jguimpel @ Serial (up) 743  
Permanent link to this record
 

 
Author del Corro, P. G.; Imboden, M.; Bishop, D. J.; Pastoriza, H. url  doi
openurl 
  Title Comb Drive Designs With Minimized Levitation Type Journal Article
  Year 2016 Publication Journal of Microelectromechanical Systems Abbreviated Journal Journal of Microelectromechanical Systems  
  Volume 25 Issue 6 Pages 1025-1032  
  Keywords driver circuits; electrostatic actuators; microfabrication; Mems; capacitive comb drive design; comb finger polarity; comb geometry optimization; control electrode; distance 3.6 mum; electric field; electrostatic actuation; levitation effect elimination; polyMUMP technology; vertical force suppression; voltage 80 V; Capacitance; Force; Levitation; Micromechanical devices; Mobile communication; Springs; Substrates; Mems; actuators; comb drives; levitation  
  Abstract This paper presents two capacitive comb drive

designs for electrostatic actuation of MEMS with the aim to

eliminate the levitation effect often observed in such systems.

By placing a shield over the comb drive fingers, it is possible

to balance the electric field and suppress vertical forces while

maintaining the desired lateral motion. By optimizing the comb

geometry, we demonstrate that our approach is able to reduce the

levitation by an order of magnitude and unwanted coupling of

motion from out-of-plane to in-plane by a factor of 7 compared

with standard comb architectures fabricated using PolyMUMPs

technology, without the need of alternating comb finger polarities

or additional control electrodes. Levitation was reduced to

160 nm, for 3.6-µm lateral displacement at a driving voltage

of 80 V.
 
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1057-7157 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial (up) 744  
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