Extracting clean fetal electrocardiogram (fECG) signals from non-invasive abdominal ECG recordings for monitoring the health of the fetus during pregnancy and labor remains a big challenge. The proposed system for facing extraction, processing and morphological feature estimation was implemented in LabVIEW 2013 with preinstalled Biosignal Filtering, Advanced Signal Processing and Digital Filter Design Toolboxes. The present approach is based on the using of FastICA algorithm for fECG extraction. In order to improve fECG extraction performance, it was applied here a combination of Undecimated Wavelet Transform (UWT) and Fast Fourier Transform (FFT) – Inverse Fast Fourier Transform (IFFT) algorithm as post-processing tool. Fetal ECG morphological indicators like heart rate, T/QRS ratio and QT interval could be estimated from fECG post-processed signals of two patients and some considerations regarding to the fetal stress during labor could be made in these two cases

The microporous layer (MPL) constitutes a critical component of the gas diffusion layer within the membrane electrode assembly (MEA) of a proton exchange membrane fuel cell (PEM FC). The MPL plays a fundamental role in various processes during FC operation: control of membrane humidification, heat distribution throughout the MEA, excess water removal from the cathode, and transportation of fuel to the reaction sites. Previously, we investigated the performance of a fuel cell unit employing an MPL based on laser-induced graphene (LIG) produced by the laser pyrolysis of polymeric (polyimide) substrates. The prototype LIG-based unit was tested over the typical range of relative humidity and temperature conditions. The polarization curves observed in that study displayed broad ohmic loss regions and high stability along the concentration loss regions, an interesting electrical behavior that justified developing the present voltage-current density study for the same FC prototype compared to one bearing a commercial pyrolytic carbon black MPL. The same operating conditions as in the first study were applied, in order to properly compare the performance efficiencies between the two systems; these are evaluated by considering the thermodynamic losses influence on the exergy efficiency, to exceed any limitations inherent in the classical energy efficiency analysis.

The efficient recovery of the waste heat from the industrial sector can represent an essential step in global energy saving, with the proper usage of other on-grid power resources available for specific high-energy consumers. A simple, low–cost energy conversion system was tested here to...

A hydrodynamic cavitation method was used to maximize the effect of destructuration of a honeycomb monolithic support of a spent Selective Catalyst Reduction (SCR) catalyst—V₂O₅-WO₃/TiO₂-type—for extracting crystalline titanium and tungsten oxides from the cordierite surface. A high relative inlet pressure of 40 MPa was applied to a divergent nozzle for obtaining high shear stresses of the submerged cavitating jets and intensive micro- and nano-jets and shock waves acting on the particle surface of the milled catalyst. Scanning Electron Microscopy (SEM) analysis indicated the compact morphology of the thin metal oxide layer at the surface of the cordierite support and the high content of Ti and W elements in the sample. Energy dispersive spectroscopy (EDAX) performed along with TEM investigations on different nano-zones from the sample established the elemental composition of WO₃-TiO₂ agglomerates separated after hydrodynamic cavitation processing and identified as independent nanocrystalline structures through Bright Field Transmission Electron Microscopy (BF-TEM) and High Resolution Transmission Electron Microscopy (HR-TEM) measurements. The tetragonal anatase phase of TiO₂ and cubic phase of WO₃ were established by both interplanar d spacing measurements and X-ray diffraction analysis. The photoelectrochemical results showed the possible second life application of automotive catalysts.

The flow field configuration in a bipolar plate represents an important factor for performance enhancement of Proton Exchange Membrane Fuel Cells (PEMFC). The sub-rib convection of reactant gases and pressure drop along the gas channel, which are affecting the oxygen supply at the catalyst electrode active area and the electrochemical reaction rate at cathode, are influenced by some geometrical flow field factors like channel/rib width and channel cross sectional area. In this study, the overall under-rib convection along the entire active area is quantified in the form of Peclet number for seven single serpentine – two channels flow field models, differing by their geometrical dimensions: channel width, height and length and distance between channels (rib width). The Finite Element Method (FEM) based Comsol Multiphysics software (vers. 5.2) is used here for numerically computing the convective type velocity field distribution along gas diffusion layer (GDL) and local current density distribution at oxygen reaction site boundary for all the models investigated. Pressure drop along the channel length, oxygen molar concentration and oxygen diffusive flux at the cathode boundary is also evaluated numerically.

The numerical model investigated in this paper was implemented with Finite Element Method (FEM) based Comsol Multiphysics software, starting from a real cross-flow micro heat exchanger manufactured from 50 stainless steel plates for cold and hot fluid transfer. Each plate (foil) had 34 microchannels with rectangular cross-section, at a depth of 100 μm and a width of 200 μm. The working fluids were water and Al₂O₃-water nanofluids with volumetric concentrations of 0.5%, 1% and 1.5% in the temperature domain of 293 – 333 K. The oxide-based nanofluids are widely investigated in thermal energy transfer applications due to an increased heat transfer performance by comparing with pure water as a cooling fluid. Analytical models for the physical properties of water and nanofluid, referring to density, viscosity, thermal conductivity and specific heat capacity were used here. Microchannel bulk temperature profiles for cold and hot plates of the model with 1% Al₂O₃-water nanofluid were presented here in order to examine the uniformity of temperature distribution in the channel flow field area. Simulation results indicated that the total heat flow rate in the heat exchanger models increased with the increase in volume concentration of the nanoparticles at mass flow rates of 41, 61, 81, 101 and 150 Kg/h, but with the expense of a bigger pressure drop (or Fanning friction factor) at an increased pumping power required to drive flow through the channels.