Modelling Dynamically Re-sizeable Electrodes (DRE) for Targeted Transcutaneous Measurements in Impedance Plethysmography

Impedance plethysmography of extremities typically uses band electrodes around limbs to monitor changes in blood volume. This often causes monitored blood variations to only generate minuscule impedance values relative to the measured baseline, attributed to the tissue surrounding the artery or vein of interest. Smaller, ECG type electrodes can provide a larger signal, however their output is very easily affected by the placement of the electrodes relative to the targeted vasculature. This paper presents a novel method to adjust the active surface of electrodes, introducing Dynamically Re-sizeable Electrodes (DRE), to only target the exact area of interest, forming localised electrodes, without having to manually re-position them. Elongated rectangular electrodes were partitioned into smaller electrode segments, interconnected through custom circuitry. For the development and assessment of the DRE system, work was carried out both experimentally in-vitro on gelatine phantoms using custom switching circuits and through finite element modelling (FEM) simulations in COMSOL. A scanning sequence made use of DRE in single segment variable tetra-pole (SSVT) mode proved capable to identify the transcutaneous location of the blood vessel of interest and the specific electrode segments located in its vicinity. Impedance measurements were then taken using these segments connected to form localised electrodes only placed over the targeted vessel. The resulting localised electrodes exhibited up to 28% increased sensitivity to blood variations relative to larger electrodes

Epitaxial growth of Cu (001) on Si (001): Mechanisms of orientation development and defect morphology

We describe the evolution of microstructure during ultrahigh vacuum ion beam sputter deposition of Cu (001) at room temperature on hydrogen-terminated Si (001). In situ reflection high energy electron diffraction indicates growth of an epitaxial Cu (001) film on Si (001) with the intensity of the Bragg rods sharpening during 5–20 nm of Cu film growth. Post-growth x-ray diffraction indicates the Cu film has a mosaic spread of (001) textures of about ±2° and that a small fraction (0.001–0.01) is of (111) textures. High-resolution transmission electron microscopy shows an abrupt Cu/Si interface with no interfacial silicide, and reveals an evolution in texture with Cu thickness so as to reduce the mosaic spread about (001). Moiré contrast suggests a nearly periodic elastic strain field extending into the Cu and Si at the interface. Other aspects of film growth which are critical to epitaxy are also discussed

Experimental and numerical investigation on micro deep drawing process of stainless steel 304 foil using flexible tools

Flexible forming technology provides significant application potential in various areas of manufacturing, particularly at a miniaturized level. Simplicity, versatility of process and feasibility of prototyping makes forming techniques by using flexible tools suitable for micro sheet metal forming. This paper reports the results of FE simulation and experimental research on micro deep drawing processes of stainless steel 304 sheets utilising a flexible die. The study presents a novel technique in which an initial gap (positive or negative) is adopted between an adjustment ring and a blank holder employed in the developed forming system. The blank holder is moveable part and supported by a particular spring that provides the required holding force. The forming parameters (anisotropy of SS 304 material, initial gap, friction conditions at various contact interfaces and initial sheet thickness) related with the forming process are in details investigated. The FE models are built using the commercial code Abaqus/Standard. The numerical predictions reveal the capability of the proposed technique on producing micro metallic cups with high quality and large aspect ratio. To verify these results, number of micro deep drawing experiments is conducted using a special set up developed for this purpose. As providing a fundamental understanding is required for the commercial development of this novel forming technique, hence the optimization of the initial gap in accordance with each sheet thickness, thickness distribution and punch force/stroke relationship are detected

Analytical solution for cauchy reaction-diffusion problems by homotopy perturbation method

In this paper, the homotopy-perturbation method (HPM) is applied to obtain approximate analytical solutions for the Cauchy reaction-diffusion problems. HPM yields solutions in convergent series forms with easily computable terms. The HPM is tested for several examples. Comparisons of the results obtained by the HPM with that obtained by the Adomian decomposition method (ADM), homotopy analysis method (HAM) and the exact solutions show the efficiency of HPM

Evolution of structural and magnetic properties in Ta/Ni_81Fe_(19) multilayer thin films

The interdiffusion kinetics in short period (12.8 nm) Ta/Ni81Fe19 polycrystalline multilayer films has been investigated and related to the evolution of soft magnetic properties upon thermal annealing in the temperature range 300-600-degrees-C. Small angle x-ray diffraction and transmission electron microscopy were used to estimate the multilayer period. Interdiffusion in the multilayers was directly computed from the decay of the satellites near (000) in a small angle x-ray diffraction spectrum. A kinetic analysis of interdiffusion suggests that grain growth is concurrent with grain boundary diffusion of Ta in Ni81Fe19. The evolution of soft magnetic properties of Ni81Fe19, i.e., lowering of 4piM(s) and increase in coercivity H(c), also lend support to the above analysis

Variable viscosity and thermophoresis effects on Darcy mixed convective heat and mass transfer past a porous wedge in the presence of chemical reaction

An analysis is presented to investigate the effect of thermophoresis particle deposition and variable viscosity on Darcy mixed convective heat and mass transfer of a viscous, incompressible fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform Darcian porous medium in order to allow for possible fluid wall suction or injection. The viscosity of the fluid is assumed to be a inverse linear function of temperature. The results are analyzed for the effect of different physical parameters, such as variable viscosity, magnetic, chemical reaction and thermophoresis parameters, on the flow, the heat and mass transfer characteristics

Inclined Magnetic Field Effects on Chaotic Convection for Moderate Prandtl Number

Using the theory of dynamical systems, this study investigated the effects of the inclined magnetic field on chaotic behaviour in a fluid layer heated from below for moderate Prandtl number. A low-dimensional, Lorenz-like model was obtained using the Galerkin truncated approximation. The fourth-order Runge-Kutta method was employed to solve the nonlinear system. The solution shows that it is possible to delay the chaotic convection depending on the Hartmann number

Assessment 0f Proximate, Mineral Elements and Amino Acids Profile of Weaning Food Formulated From a Local Variety of Pennisetum Glaucum, Roasted Sesanum Indicum and Euastacus Spp

Sprouted cereal and legume complementary weaning food were prepared from a local variety of Millet, Sesame seed and crayfish, the complementary flour blends were mixed into various ratios 60:20:20 as MSC (60 parts of millet: 20 parts of sesame and 20 parts of crayfish), 65:35 as MS (65 parts of millet and 35 parts sesame) and 75:25 MC (75 parts of millet, and 25 parts of crayfish) respectively, hence compared with commercial weaning food celarac Cl. A standard methods were used for the analysis .Crude protein, crude fat, crude fiber of the formulation increase significantly (p≤0.05) which ranged from 20.10±0.15, 17.52±0.02 and 9.22±0.06 compared to the reference value of 18.50±0.34, 8.31±0.30 and 0.11±0.01 respectively. Moisture and ash content values were higher compared to the reference values as 8.25±0.025 and 4.78±0.08 to 5.58±0.01 and 1.94±0.01. Elements composition of sodium 114.71±1.33, iron 4.72±0.05, calcium 389.14±0.03 and zinc 3.03±0.03 were significantly higher than the reference value 15.86±0.08, 1.62±0.01, 110.62±0.39 and 1.28±0.01 respectively. While the values of Magnesium, Phosphorous, and potassium are lower compared to the reference value. Amino acids content showed a significant increase in the contents of lysine 3.95±0.01, methionine 2.43±0.01 and tryptophan 3.75±0.02 to that of the reference value 2.70±0.0.01, 1.24±0.01 and 2.27±0.01. Functional properties with WSI and FC are significantly low compared to the formulated diets as 288.00±1.00 and 360.00±1.00 to 391.00±1.00 and 502.00±1.00 respectively. Key words: Sprouted, formulation, weaning food, millet, sesame and crayfish. DOI: 10.7176/JNSR/13-18-07 Publication date: December 31st 202