Performance improvement of an AC electroosmotic micropump by hydrophobic surface modification

This paper describes the improvement of bi-directional micropump velocity by deposition of a hydrophobic nanocomposite monolayer. A polymer base nanocomposite coating consisting of a homogeneous mixture of silicon nanoparticles in polydimethylsiloxane (PDMS) is used to improve the hydrophobicity of the micropump surfaces. For hydrophobic nature of PDMS and the monolayer coating with nanoscale surface roughness, the hydrophilic surface of a biased AC electroosmotic micropump will transform to a hydrophobic surface. In our previous research the applied AC voltage, frequency, channel dimension, and electrode width were optimized (Islam and Reyna, Electrophoresis 33(7), 2012). Based on the prior results obtained for the biased AC electroosmotic micropump, the pumping velocity was 300 micron/s in 100-μm channel thickness for applied voltage of 4.4 V at 1 kHz frequency. Here in this work, improvement of the micropump velocity is investigated through a surface modification process. The highest velocity of 450 micron/s is observed by modifying the surface characteristics. This paper will also discuss the synthesis process and characteristics of the polymer base nanocomposite monolayer. In addition to hydrophobicity improvement, adding a thin nanocomposite monolayer will physically separate the electrodes from the pumping liquid, thus eliminating their reaction, which is usually observed due to the application of voltage. As a result, higher voltages can be applied to the electrodes and higher pumping rates are achievable.     

Estimation of the evacuation time in an emergency situation in hospitals

In this paper, a prediction model is presented that estimates the evacuation time in an emergency situation for hospitals. The model is generic enough to be used in various hospital settings. This model can provide incident managers with estimates of the evacuation times of different types of patients and can offer support to the managers with their resource allocation decisions in emergency situations. The major advantage of the prediction model is that the computation time is very short and the model does not need a lengthy and costly design. The model was applied for several different evacuation scenarios and the results were compared with those of a simulation model which had already been designed for use by the hospital. The comparison shows that the prediction model can provide estimates of the evacuation time that are similar to the results found by using costly and time-consuming simulation models.     

Thermal Integration of Sulfuric Acid and Continuous Catalyst Regeneration of Naphtha Reforming Plants

An optimal reactor design is proposed that simultaneously improves the naphtha reforming reactor performance and increases sulfur trioxide production. In this new configuration, the naphtha reforming process as an endothermic reaction is coupled with the oxidation reaction of sulfur dioxide, which is an exothermic reaction. The differential evolution optimization technique is applied to maximize the produced amounts and yields of aromatics and hydrogen. The results obtained with the optimized thermally coupled reactor are compared with those of the conventional and thermally coupled reactors, proving the superiority of the proposed configuration.     

Audio-visual emotion recognition using FCBF feature selection method and particle swarm optimization for fuzzy ARTMAP neural networks

Multimedia Tools and Applications - Humans use many modalities such as face, speech and body gesture to express their feeling. So, to make emotional computers and make the human-computer...     

Effects of the porous medium and water-silver biological nanofluid on the performance of a newly designed heat sink by using first and second laws of thermodynamics

The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink (HS) filled with porous foam (PHS) using first and second laws of thermodynamics. The impacts of inlet velocity (V = 0.5–3 m·s⁻¹) and volume fraction of nanofluid (φ = 0–1%) on the performance metrics of HS are assessed and the outcomes are compared with those of the non-porous HS (NHS). The outcomes revealed that for both the PHS and NHS, the increase of V causes an intensification in convection coefficient, pumping power, and entropy generation due to fluid friction, while the maximum CPU temperature, thermal resistance, and entropy generation due to the heat transfer reduces by boosting V. Also, it was found that the augmentation of V results in intensification in convection coefficient, pumping power, overall hydrothermal performance, and frictional entropy generation, while the opposite is true for maximum CPU temperature, thermal resistance, and thermal entropy generation. Furthermore, it was reported that, except for φ = 0.5%, the overall hydrothermal performance of NHS is better than that of PHS, while PHS has better second-law performance than NHS in all the studied cases. Also, it can be concluded that the best hydrothermal performance for PHS belongs to φ = 1% and V = 0.5 m·s⁻¹, while for NHS, these values are 1% and 2 m·s⁻¹.     

Effect of the Geometry of a Swirl Generator on Energy Loss and Shockwave Position in Arina Nozzle

To investigate the effect of the swirl generator (SG) on shockwave position and pressure drop, 3D simulation is conducted and validated by Arina's study. An increase of the blade number, height, and end angle leads to shockwave displacement toward the nozzle outlet. The maximum increment of the shockwave displacement, which is due to enlarging the angle of the blade end, is about 47 %. For this case, the pressure drop share of the SG is nearly half of the total pressure drop, while the residence time of particles is prolonged by about 51 %. As a general finding, increasing the swirl intensity provides a longer residence time to separate adequately the liquid from the gas. However, a higher energy loss is not desirable for the high-pressure process at the downstream of the 3S separator.     

Modeling of naphtha reforming unit applying detailed description of kinetic in continuous catalytic regeneration process

Naphtha reforming is one of the most important processes in refineries in which high value-added reformate for gasoline pool and aromatics such as benzene, toluene, and xylene are produced. It is necessary to establish new naphtha reforming units and develop the traditional units to increase the efficiency of the processes. In this study, according to the recent progresses in the naphtha reforming technology, mathematical modeling of this process in continuous catalyst regeneration mode of operation is accomplished in two dimensions (radial and axial) by considering cross flow pattern. In addition, a new catalyst deactivation model has been proposed and a new reaction network model based on 32 pseudo-components with 84 reactions is investigated. Then, this model has been validated by comparing with industrial data, and its results have acceptable agreement.     

Preparation and photocatalytic study of CoFe2O4/TiO2/Au nanocomposites and their applications in organic pollutant degradation and modeling by an artificial neural network (ANN)

Journal of Materials Science: Materials in Electronics - Due to the increase of environmental pollution by various industries in recent decades, preparing drinking water has become one of the most...     

Effects of the trench geometry on vibration mitigation level in high-speed railway tracks

Train-induced ground vibration is numerically analyzed using the finite element method (FEM) in this paper. Varieties of open trenches including partial and full length systems with different geometries are employed as the vibration mitigation strategies. Ground is modeled by multiple soil layers and the train load pattern is simulated by series of successive moving loads. A parametric study is then carried out after verification of the numerical model. Effects of different parameters including the trench type, size and geometry and the train speed on the vibration mitigation level are investigated. The operational speeds are set to be in vicinity of the Rayleigh wave propagation velocity. Two types of active and passive trenches are considered with three different geometries consisting of rectangular, triangular (wedge) and circular cross sections.     

What is this page known for? Computing Web page reputations

The textual content of the Web enriched with the hyperlink structure surrounding it can be a useful source of information for querying and searching. This paper presents a search process where the input is the URL of a page, and the output is a ranked set of topics on which the page has a reputation. For example, if the input is www.gamelan.com, then a possible output is ‘Java'. We propose several algorithmic formulations of the notion of reputation using simple random walk models of Web-browsing behavior. We give preliminary test results on the effectiveness of these algorithms.