Fernando Pinho

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We study the flow of a Newtonian fluid through microfabricated hyperbolic contractions in detail. A set of planar converging geometries, with total Hencky strains ranging from 1 to 3.7, have been fabricated in order to produce a homogeneous extensional flow field within the contraction. The kinematics in the contraction region are investigated(More)
This paper reports the development and application of a finite-volume based methodology for the calculation of the flow of fluids which follow differential viscoelastic constitutive models. The novelty of the method lies on the use of the non-staggered grid arrangement, in which all dependent variables are located at the center of the control volumes, thus(More)
In this study, we show the importance of extensional rheology, in addition to the shear rheology, in the choice of blood analog solutions intended to be used in vitro for mimicking the microcirculatory system. For this purpose, we compare the flow of a Newtonian fluid and two well-established viscoelastic blood analog polymer solutions through microfluidic(More)
Most of the environments where mobile robots are deployed offer a comprehensive networking infrastructure. In order to take part of these environments, mobile robots must enhance not only their communication capabilities, but also their interaction capabilities. Current robotic frameworks are oriented to gather data from the robotic sensors and to act on(More)
The non-Newtonian properties of blood are of great importance since they are closely related with incident cardiovascular diseases. A good understanding of the hemodynamics through the main vessels of the human circulatory system is thus fundamental in the detection and especially in the treatment of these diseases. Very often such studies take place in(More)
As mobile robots become part of large networked infrastructures, concerns about the integration of robots into distributed applications arise. Due to the predominance of the Web protocols, it is natural mobile robots to employ such protocols for interacting over the network with other applications. Information transfer protocols such as HTTP and SOAP allow(More)
This paper presents an analytical model that describes a two-fluid electro-osmotic flow of stratified fluids with Newtonian or viscoelastic rheological behavior. This is the principle of operation of an electro-osmotic two-fluid pump as proposed by Brask et al. [Tech. Proc. Nanotech., 1, 190-193, 2003], in which an electrically non-conducting fluid is(More)
We present an experimental investigation of viscoelastic fluid flow in a cross-slot microgeometry under low Reynolds number flow conditions. By using several viscoelastic fluids, we investigate the effects of the microchannel bounding walls and the polymer solution concentration on the flow patterns. We demonstrate that for concentrated polymer solutions,(More)
The electro-osmotic flow of a viscoelastic fluid between parallel plates is investigated analytically. The rheology of the fluid is described by the Phan-Thien-Tanner model. This model uses the Gordon-Schowalter convected derivative, which leads to a non-zero second normal stress difference in pure shear flow. A nonlinear Poisson-Boltzmann equation(More)
In this work, a new experiment al device to visualize the filling of containers, under controlled and reproducible conditions, is described and employed to study the various phenomen a that occur during container filling with Newtonian fluids. The experimental results displayed a variety of flow patterns, including the phenomenon of jet buckling. The(More)