scholarly journals Programmable droplet manipulation and wetting with soft magnetic carpets

2021 ◽  
Vol 118 (46) ◽  
pp. e2111291118
Author(s):  
Ahmet F. Demirörs ◽  
Sümeyye Aykut ◽  
Sophia Ganzeboom ◽  
Yuki A. Meier ◽  
Erik Poloni
Keyword(s):  
Magnetic Field ◽  
Contact Angle ◽  
Potential Method ◽  
Field Application ◽  
Small Scale ◽  
Soft Magnetic ◽  
Chemical Waste ◽  
Wetting Properties ◽  
Energy Applications ◽  
Droplet Manipulation

The ability to regulate interfacial and wetting properties is highly demanded in anti-icing, anti-biofouling, and medical and energy applications. Recent work on liquid-infused systems achieved switching wetting properties, which allow us to turn between slip and pin states. However, patterning the wetting of surfaces in a dynamic fashion still remains a challenge. In this work, we use programmable wetting to activate and propel droplets over large distances. We achieve this with liquid-infused soft magnetic carpets (SMCs) that consist of pillars that are responsive to external magnetic stimuli. Liquid-infused SMCs, which are sticky for a water droplet, become slippery upon application of a magnetic field. Application of a patterned magnetic field results in a patterned wetting on the SMC. A traveling magnetic field wave translates the patterned wetting on the substrate, which allows droplet manipulation. The droplet speed increases with an increased contact angle and with the droplet size, which offers a potential method to sort and separate droplets with respect to their contact angle or size. Furthermore, programmable control of the droplet allows us to conduct reactions by combining droplets loaded with reagents. Such an ability of conducting small-scale reactions on SMCs has the potential to be used for automated analytical testing, diagnostics, and screening, with a potential to reduce the chemical waste.

scholarly journals On the through-process texture evolution assessment in grain oriented Fe-3 wt% Si steel produced by a novel directional inoculation technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Snehashish Tripathy ◽  
Sandip Ghosh Chowdhury
Keyword(s):  
Magnetic Field ◽  
Hot Rolling ◽  
Texture Evolution ◽  
Lattice Parameter ◽  
Soft Magnetic ◽  
Oriented Growth ◽  
Inoculation Technique ◽  
Hot Band ◽  
Ebsd Technique ◽  
Cast Microstructure

AbstractA novel directional inoculation technique has been designed to cast thin slab ingots containing Goss (or near Goss) oriented components in the as cast microstructure under the combined effect of oriented nucleation and oriented growth. The same has been targeted so as to retain Goss orientations and simultaneously develop γ fiber components (ranging from {111}<$$1\overline{1}0$$ 1 1 ¯ 0 > to {111}<112>) during hot rolling. The designed scheme of directional inoculation achieved oriented nucleation by the effect of exogenously added soft magnetic inoculants under magnetic field and oriented growth by the effect of fast cooling rates prevailing in the mould. The choice of 65Fe–35Co (wt%) system as soft magnetic inoculants was made taking into account the similarity in crystal structure and lattice parameter. The chemically synthesized inoculants under the effect of external magnetic field during solidification were able to exhibit directional inoculation. Variation in the cast microstructure and microtexture by varying the extent of inoculant addition was studied by EBSD technique. The ingots cast under different conditions were subjected to a designed hot rolling schedule and the through process microstructural and microtextural evolution was assessed. It was observed that fine equiaxed grains with initial cube orientations in the as cast structure could lead to the most desirable microstructural as well as microtextural gradient in the hot band.

Experimental investigations on finishing of a brass specimen by magneto-rheological honing technique

2021 ◽  
pp. 251659842110157
Author(s):  
Chinu Kumari ◽  
Sanjay Kumar Chak
Keyword(s):  
Magnetic Field ◽  
Process Parameters ◽  
Surface Finish ◽  
Rotational Speed ◽  
Field Application ◽  
Surface Finishing ◽  
Experimental Investigations ◽  
Significant Parameter ◽  
Magnetizing Current ◽  
Magneto Rheological

Magneto-rheological abrasive honing (MRAH) is an unconventional surface finishing technique that relies on abrasives mixed with a unique finishing fluid, which changes its characteristics on magnetic field application. This process imparts nanometric-level surface finish with a significant amount of uniformity. Rotating motion of the workpiece and continuous reciprocation of the finishing fluid in the MRAH process are recognized as the major aspects for adopting this process in finishing non-magnetic materials. The finishing obtained through the MRAH process relies on the workpiece’s material properties and process parameters such as concentration of abrasives in finishing fluid, rotational speed of the workpiece, and magnetic field strength/magnetizing current. To study the efficacy of MRAH process, a parametric study was conducted by performing few experiments on a brass workpiece. Design of experiment approach was adopted to plan the experiments, and the effect of different values of magnetizing current, the concentration of abrasives, and rotational speed on the surface finish were analyzed through the application of analysis of variance (ANOVA). From ANOVA, the rotational speed was found as the most significant parameter with a contribution of 48.90% on % reduction in roughness value (%∇Ra). Around 57% of roughness reduction was obtained at the optimized value of process parameters.

scholarly journals The Evolution of the Solar Magnetic Field

2012 ◽  
Vol 10 (H16) ◽  
pp. 86-89 ◽  
Author(s):  
J. Todd Hoeksema
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Magnetic Field ◽  
Coronal Holes ◽  
Active Regions ◽  
Statistical Characteristics ◽  
Field Pattern ◽  
Small Scale ◽  
Polar Caps ◽  
Magnetic Elements

AbstractThe almost stately evolution of the global heliospheric magnetic field pattern during most of the solar cycle belies the intense dynamic interplay of photospheric and coronal flux concentrations on scales both large and small. The statistical characteristics of emerging bipoles and active regions lead to development of systematic magnetic patterns. Diffusion and flows impel features to interact constructively and destructively, and on longer time scales they may help drive the creation of new flux. Peculiar properties of the components in each solar cycle determine the specific details and provide additional clues about their sources. The interactions of complex developing features with the existing global magnetic environment drive impulsive events on all scales. Predominantly new-polarity surges originating in active regions at low latitudes can reach the poles in a year or two. Coronal holes and polar caps composed of short-lived, small-scale magnetic elements can persist for months and years. Advanced models coupled with comprehensive measurements of the visible solar surface, as well as the interior, corona, and heliosphere promise to revolutionize our understanding of the hierarchy we call the solar magnetic field.

Preparation and the Blood Compatibility of Titanium Oxide Nanorod Arrays

2011 ◽  
Vol 306-307 ◽  
pp. 25-30 ◽  
Author(s):  
Ping Luo ◽  
Zhan Yun Huang ◽  
Di Hu Chen
Keyword(s):  
Contact Angle ◽  
Surface Morphology ◽  
Titanium Oxide ◽  
Tin Oxide ◽  
Growth Parameters ◽  
Blood Compatibility ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Nanorod Arrays ◽  
Wetting Properties

In this work, titanium oxide nanorod arrays were fabricated by using the hydrothermal method on fluorine-doped tin oxide (FTO) coated glass. The diameter of the nanorods could be controlled from 150 nm to 30 nm by changing the growth parameters. The surface morphology and the structure of the samples were characterized by SEM and XRD. The wetting properties were identified by contact angle measurement. Platelet attachment was investigated to evaluate the blood compatibility of the samples with different nanoscale topographies. Results show that the nanotopographical surfaces perform outstanding blood compatibility, and the adhering platelet decreased with the increasing diameter of the nanorods.

scholarly journals On the origin of variable structures in the winds of hot luminous stars

2013 ◽  
Vol 440 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Yannick J. L. Michaux ◽  
Anthony F. J. Moffat ◽  
André-Nicolas Chené ◽  
Nicole St-Louis
Keyword(s):  
Magnetic Field ◽  
Empirical Evidence ◽  
Temporal Variability ◽  
Large Scale ◽  
Small Scale ◽  
Ionization Zone ◽  
Corotating Interaction Regions ◽  
Wind Variability ◽  
Global Magnetic Field ◽  
Interaction Regions

Abstract Examination of the temporal variability properties of several strong optical recombination lines in a large sample of Galactic Wolf–Rayet (WR) stars reveals possible trends, especially in the more homogeneous WC than the diverse WN subtypes, of increasing wind variability with cooler subtypes. This could imply that a serious contender for the driver of the variations is stochastic, magnetic subsurface convection associated with the 170 kK partial-ionization zone of iron, which should occupy a deeper and larger zone of greater mass in cooler WR subtypes. This empirical evidence suggests that the heretofore proposed ubiquitous driver of wind variability, radiative instabilities, may not be the only mechanism playing a role in the stochastic multiple small-scaled structures seen in the winds of hot luminous stars. In addition to small-scale stochastic behaviour, subsurface convection guided by a global magnetic field with localized emerging loops may also be at the origin of the large-scale corotating interaction regions as seen frequently in O stars and occasionally in the winds of their descendant WR stars.

MAGNETIC FIELD AMPLIFICATION BY RELATIVISTIC SHOCKS IN AN INHOMOGENEOUS MEDIUM

2012 ◽  
Vol 08 ◽  
pp. 364-367
Author(s):  
YOSUKE MIZUNO ◽  
MARTIN POHL ◽  
JACEK NIEMIEC ◽  
BING ZHANG ◽  
KEN-ICHI NISHIKAWA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Inhomogeneous Medium ◽  
Magnetic Energy ◽  
Small Scale ◽  
Two Dimensional ◽  
Filamentary Structure ◽  
Field Amplification ◽  
Relativistic Shocks ◽  
Field Lines ◽  
Magnetohydrodynamic Simulations

We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity, and the magnetic field is strongly amplified due to the stretching and folding of field lines in the turbulent velocity field. The amplified magnetic field evolves into a filamentary structure in two-dimensional simulations. The magnetic energy spectrum is flatter than the Kolmogorov spectrum and indicates that the so-called small-scale dynamo is occurring in the postshock region. We also find that the amplitude of magnetic-field amplification depends on the direction of the mean preshock magnetic field.

scholarly journals Numerical Simulation of the Time Evolution of Small-Scale Irregularities in the F-Layer Ionospheric Plasma

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
O. V. Mingalev ◽  
G. I. Mingaleva ◽  
M. N. Melnik ◽  
V. S. Mingalev
Keyword(s):  
Magnetic Field ◽  
Time Evolution ◽  
Ionospheric Plasma ◽  
Debye Length ◽  
Small Scale ◽  
System Of Equations ◽  
Applied Model ◽  
Positive Ions ◽  
F Region ◽  
Small Scale Irregularity

Dynamics of magnetic field-aligned small-scale irregularities in the electron concentration, existing in the F-layer ionospheric plasma, is investigated with the help of a mathematical model. The plasma is assumed to be a rarefied compound consisting of electrons and positive ions and being in a strong, external magnetic field. In the applied model, kinetic processes in the plasma are simulated by using the Vlasov-Poisson system of equations. The system of equations is numerically solved applying a macroparticle method. The time evolution of a plasma irregularity, having initial cross-section dimension commensurable with a Debye length, is simulated during the period sufficient for the irregularity to decay completely. The results of simulation indicate that the small-scale irregularity, created initially in the F-region ionosphere, decays accomplishing periodic damped vibrations, with the process being collisionless.

Long-period variations in the magnetic field of small-scale solar structures

2016 ◽  
Vol 56 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
P. V. Strekalova ◽  
Yu. A. Nagovitsyn ◽  
A. Riehokainen ◽  
V. V. Smirnova
Keyword(s):  
Magnetic Field ◽  
Small Scale ◽  
Long Period ◽  
Period Variations ◽  
The Magnetic Field

Initial Results On Medium Frequency Electromagnetic Field Penetration In Biological Soft Tissue

2012 ◽  
Author(s):  
Zulkarnay Zakaria ◽  
Mohd Fahajumi Jumaah ◽  
Mohd Saiful Badri Mansor ◽  
Khairi Mat Daud ◽  
Mohd Hafiz Fazalul Rahiman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Soft Tissue ◽  
Soft Tissues ◽  
Low Cost ◽  
The Body ◽  
Small Scale ◽  
Medium Frequency ◽  
Magnetic Field Penetration ◽  
Magnetic Induction Tomography ◽  
Field Penetration

Terapi merupakan antara teknik perubatan tertua dalam mengekalkan kesihatan badan terutama daripada aliran darah yang tidak baik, strok dan beberapa penyakit yang lain. Teknik ini termasuklah akupuntur, guasa dan juga urutan. Terdapat juga teknik terapi moden seperti terapi warna, terapi ozon, terapi dadah dan banyak lagi. Kertas kajian ini akan mengetengahkan penjana terapi elektromagnet, satu alat yang mempunyai potensi aplikasi terapi dalam bidang perubatan. Alat ini menghasilkan medan magnet berfrekuensi sederhana sebagai sumber terapi. Perkakasan yang berskala kecil berfrekuensi sederhana dan berkos rendah ini telah dibangunkan dan telah diuji pada tisu biologi bagi mengukur tahap ketembusan medan magnet. Ujian ini telah membuktikan bahawa medan magnet yang telah dihasilkan mampu menembusi tisu lembut bersaiz sehingga 2 cm dengan jarak 7 cm daripada sumber. Kebolehan penembusan sistem ini terhadap tisu lembut memberikan peluang yang cerah kepada kajian ini memandangkan medan magnet telah menunjukkan potensi sebagai sebahagian daripada terapi untuk memulihkan migraine, strok, kekejangan dan beberapa yang lain selain boleh diaplikasikan dalam pengimejan tomografi induksi magnet. Kata kunci: Terapi elektromagnet, medan magnet, penembusan, tisu lembut, aplikasi perubatan Therapy is among the oldest medication technique in maintaining the health of the body especially from bad blood circulation, stroke and several others. This technique includes acupuncture, guasa and also massage. There are also modern therapy techniques like colour therapy, water therapy, ozone therapy, drug therapy and others. This paper will highlight electromagnetic therapy generator, a device which has the potential of therapy application in medical field. This device produce medium frequency magnetic field as a therapy source. This small scale medium frequency and low cost hardware that has been developed was tested on the biological tissue for the purpose of measuring the magnetic field penetration. The testing has proven that the generated magnetic field is able to penetrate the soft tissue up to 2 cm with distance from the source up to 7 cm. The capability of the system penetrations through the soft tissues provide the bright future of this research since magnetic field have shown the potential as being part of the therapy for curing migraine, stroke, cramp and several others besides the application in the magnetic induction tomography imaging. Key words: Electromagnetic therapy, magnetic field, penetration, soft tissue; medical applications

Sign in / Sign up

Export Citation Format

Share Document