In questa sezione troverete i lavori presentati alle Conferenze mondiali COMSOL. Le presentazioni descrivono ricerche e prodotti innovativi progettati con COMSOL Multiphysics da colleghi di tutto il mondo. I temi delle ricerche presentate abbracciano un'ampia gamma di settori produttivi e aree applicative, in ambito elettrico, meccanico, fluidodinamico e chimico. Lo strumento di Ricerca Rapida vi permetterà di trovare le presentazioni che si riferiscono all'area di vostro interesse.

Sample Preconcentration in Channels with Nonuniform Surface Charge and Thick Electric Double Layers

A. Eden [1], C. McCallum [1], B. Storey [2], C. D. Meinhart [1], S. Pennathur [1],
[1] University of California Santa Barbara, Santa Barbara, CA, USA
[2] Olin College, Needham, MA, USA

We present a novel method for concentrating and focusing small analytes by taking advantage of the nonuniform ion distributions produced by thick electric double layers (EDLs) in nanochannels with heterogeneous surface charge. Specifically, we apply a voltage bias to a gate electrode embedded within the channel wall, tuning the surface charge in a region of the channel and subsequently altering ...

Secondary Flow of Liquid-liquid Two-Phase Fluids in a Pipe Bend

M. Ayala [1], P. Santos [2], G. Hamester [2], O. Ayala [3],
[1] Department of Mechanical Engineering, Universidad de Oriente, Puerto La Cruz, Venezuela
[2] Brazil Scientific Mobility Program, CAPES, Brasilia DF, Brazil
[3] Department of Engineering Technology, Old Dominion University, Norfolk, VA, USA

As the flow passed through the pipe, and entered the bend, various vortical structures appear, meaning that there is a secondary flow emerging. Also while the flow is in the bend gravity forces affect distinctively its behavior as long as the centrifugal force is not greater. From this study, it appears that the fluid behavior on the pipe bend is strongly related to gravitational and ...

Numerical Analysis of the Effect of Surface Active Elements on Marangoni Flow in a Melt Pool

K. Yadav [1], A. Mishra [1],
[1] IIT Kanpur, Kanpur, Uttar Pradesh, India

Marangoni flow affects the heat and mass transfer occurring in the molten metal regions in welding and additive manufacturing processes. It originates from the surface tension gradient (∂γ/∂T) induced at the melt pool surface due to the temperature difference. The flow pattern within melt pool affects the segregation and melt-pool shape and size. The flow pattern and therefore the melt pool ...

Multiphysical Modeling of Calcium Carbonate Transportation in UV Disinfection in Water Treatment

E. R. Blatchley[1], and B.Z. Sun[1]
[1]Department of Civil Engineering, Purdue University, West Lafayette, IN, USA

Mineral precipitation on to the quartz surface of the lamp jackets in UV disinfection process (fouling) has been recognized as a major problem for UV radiation delivery during disinfection operation. Fouling behavior was observed to be induced thermally and influenced by hydraulic character of the UV disinfection configuration. Fouling process involves momentum, heat, and mass transport within ...

Study of Artificial Molecular Engines Action Through COMSOL Multiphysics® Program

L. Moro[1], F. Lugli[1], and F. Zerbetto[1]

[1]Department of Chemistry “G. Ciamician”, Università di Bologna, Bologna, Italy

Rotaxanes are a class of molecules recently developed in laboratory that have been heralded as possible molecular motors. The motor is constituted by a linear molecule (thread) and a ring-shaped molecule (macrocycle), which is free to move along the thread, switching between two, or more, energetically stable interaction points (stations). Molecular motors start their functioning far from ...

Laminar Thermal Mixing in Coating Flows

A. Haas[1], M. Scholle[1], A. Aksel[1], H.M. Thompson[2], R.W. Hewson[2], and P.H. Gaskell[2]

[1]Department of Applied Mechanics and Fluid Dynamics, University of Bayreuth, Bayreuth, Germany
[2]School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom

Heat transfer in a plane shear flow configuration consisting of two infinitely long parallel plates is considered. In laminar flows over undulated substrates eddies can be generated due to the kinematical constraints. A closed form analytical solution for the velocity field, based on lubrication theory as well as a semi-analytic solution for the temperature field is derived for the creeping ...

Large Scale 3D Flow Distribution Analysis in HTPEM Fuel Cells

C. Siegel[1][2], G. Bandlamudi[1][2], N. van der Schoot[1], and A. Heinzel[1][2]
[1]Zentrum für BrennstoffzellenTechnik GmbH, Duisburg, Germany
[2]Institut für Energie- und Umweltverfahrenstechnik, University of Duisburg-Essen, Duisburg, Germany

Accurate bipolar-plate and flow-field layout is one crucial task for optimizing fuel cells. These cell components perform several functions, including charge transport or gas and water transport throughout the cell just to name a few. Overall, the design depends on the fuel cell application or the geometrical size of the assembly. The requirements for a flow-field used in a high temperature ...

Modeling of Nerve Stimulation Thresholds and Their Dependence on Electrical Impedance with COMSOL

P. Krastev[1], and B. Tracey[1]
[1]Neurometrix, Inc., Waltham, Massachusetts, USA

Nerve localization is important for applications in regional anesthesia. Localization is achieved by stimulating the nerve with an electric field produced by a current from a needle inserted into the body of the patient, close to the target nerve.  Modeling of the electric field in close proximity to the nerve may help to explain observed variations in threshold currents and can help to ...

Periodic Near-field Enhancement on Metal-Dielectric Interfacial Gratings at Optimized Azimuthal Orientation

M. Csete[1,2], X. Hu[1], A. Sipos[2], A. Szalai[2], A. Mathesz[2], and K. Berggren[1]

[1]Research Laboratory of Electronics, Nanostructures Laboratory, Massachusetts Institute of Technology, Massachusetts, USA
[2]Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary

The effect of plasmon-wavelength scaled gratings on the surface plasmon resonance is studied experimentally and theoretically. The model samples are multi-layers containing laser fabricated gratings at bimetal-polymer interfaces. Dual-angle dependent surface plasmon resonance measurements are performed illuminating the samples by monochromatic light in Kretschmann arrangement. The double ...

COMSOL Implementation of Valet-Fert Model for CPP GMR devices

T. Xu[1], C.K.A. Mewes[1], S. Gupta[2], and W.H. Butler[1]
[1]Department of Physics and Astronomy and Center for Materials for Information Technology, University of Alabama, Tuscaloosa, Alabama, USA
[2]Department of Metallurgical and Materials Engineering and Center for Materials for Information Technology, University of Alabama, Tuscaloosa, Alabama, USA

The Giant Magneto Resistance (GMR) effect is a quantum mechanical effect which can be observed in systems consisting of thin alternating ferromagnetic and non-ferromagnetic layers. Simulation using COMSOL allows the evaluation of the magneto-resistance ratio and the electrical resistances of realistic CPP-GMR devices and opens the possibility to study new device materials and designs.

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