Extraction of fetal electrocardiogram using adaptive neuro-fuzzy inference systems

In this paper, we investigate the use of adaptive neuro-fuzzy inference systems (ANFIS) for fetal electrocardiogram (FECG) extraction from two ECG signals recorded at the thoracic and abdominal areas of the mother's skin. The thoracic ECG is assumed to be almost completely maternal (MECG) while the abdominal ECG is considered to be composite as it contains both the mother's and the fetus' ECG signals. The maternal component in the abdominal ECG signal is a nonlinearly transformed version of the MECG. We use an ANFIS network to identify this nonlinear relationship, and to align the MECG signal with the maternal component in the abdominal ECG signal. Thus, we extract the FECG component by subtracting the aligned version of the MECG signal from the abdominal ECG signal. We validate our technique on both real and synthetic ECG signals. Our results demonstrate the effectiveness of the proposed technique in extracting the FECG component from abdominal signals of very low maternal to fetal signal-to-noise ratios. The results also show that the technique is capable of extracting the FECG even when it is totally embedded within the maternal QRS complex.     

THERMAL STRESSES FOR AN INFINITE BODY WITH A SPHERICAL CAVITY WITH TWO RELAXATION TIMES

Thermoelastic interactions caused in a homogeneous and isotropic infinite body with a spherical cavity are considered for the two different theories of generalized thermoelasticity, that is, Lord, and Shulman's theory and Green and Lindsay's theory. Analytical expressions for the temperature, displacement, and thermal stress fields are obtained; and the results are compared with the classical dynamical coupled theory.     

Efficient and High-quality Recommendations via Momentum-incorporated Parallel Stochastic Gradient Descent-Based Learning

A recommender system(RS)relying on latent factor analysis usually adopts stochastic gradient descent(SGD)as its learning algorithm.However,owing to its serial mechanism,an SGD algorithm suffers from low efficiency and scalability when handling large-scale industrial problems.Aiming at addressing this issue,this study proposes a momentum-incorporated parallel stochastic gradient descent(MPSGD)algorithm,whose main idea is two-fold:a)implementing parallelization via a novel datasplitting strategy,and b)accelerating convergence rate by integrating momentum effects into its training process.With it,an MPSGD-based latent factor(MLF)model is achieved,which is capable of performing efficient and high-quality recommendations.Experimental results on four high-dimensional and sparse matrices generated by industrial RS indicate that owing to an MPSGD algorithm,an MLF model outperforms the existing state-of-the-art ones in both computational efficiency and scalability.     

Proteolytic degradation of ewe milk proteins during fermentation of yoghurts and storage

Yoghurts are mostly produced from cow milk and to a very limited extent from ewe milk. The evolution of caseins and whey proteins in ovine milk submitted to different thermal treatments (63 degrees C/30 min; 73 degrees C/15 min; 85 degrees C/10 min or 96 degrees C/5 min) was followed during fermentation of yoghurts and during their storage up to 14 days, using two different sets of starters. One set of starter LAB was a "ropy" culture (YC-191), which is a well-defined mixed strain culture containing Streptococcus thermophilus ST-143 and Lactobacillus delbrueckii subsp. bulgaricus (LB-18 and LB-CH2). The other set of starter bacteria (YC-460) was a standard yoghurt culture("non-ropy") containing mixed strain culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Contents of free amino groups in produced yoghurts increased gradually during the fermentation, up to a maximal value obtained after 4 h fermentation, then they did not change significantly during storage of yoghurt produced with YC-191 starter. In contrary, a large drop in the amount of free amino groups was observed in the first 24 h of storage in the case of yoghurt made with YC-460 indicating that microorganisms continue still to grow in low temperatures. During fermentation and storage of both yoghurt types, alpha-lactalbumin was hydrolyzed to a slightly bigger extent than beta-lactoglobulin. During fermentation, beta-casein was slightly more degraded than alpha(s)-caseins; however, the opposite was observed during storage up to 14 days. Generally, a more intense heat pretreatment led to a higher degradation of whey proteins and caseins during fermentation and storage. Differences in proteolytic activity between the two starters used (whey proteins more degraded by YC-191; caseins more degraded by YC-460) may lead to improvement in production and formulation of yoghurts differing in their physicochemical and rheological properties.     

Grafting of vinyl acetate onto chitosan and biocidal activity of the graft copolymers

The reaction process of polycarbosilane (PCS) fiber cured by cyclohexene vapor has been studied and compared with that of PCS fiber cured by air. The influence of curing temperature on Si? H bond reaction degree and gel content, the structure and composition of PCS were investigated by FTIR, EA, TGA, NMR, and GC‐MS. The results showed that, Si? H bond in the molecular structure of PCS reacted during cyclohexene curing process and the reaction degree increased when the curing temperature increases. Simultaneously, gel content of PCS fiber rapidly increased till PCS fiber became infusible. Si? H radical and Si? CH₂ radicals formed Si? CH₂? Si crosslinking of PCS molecules through the agency of cyclohexene. Some cyclohexyls linked to principal chain of PCS, which was proven by ¹³C‐CPMAS‐NMR, and broke off, and cyclohexane and some monosilane are generated as byproducts when temperature increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Electrochemical and molecular dynamics simulation studies on the corrosion inhibition of aluminum in molar hydrochloric acid using some imidazole derivatives

The corrosion inhibition and adsorption characteristics of three selected imidazole derivatives namely, 2-amino-4,5-imidazoledicarbonitril (AID), 5-amino-4-imidazolecarboxamide (AIC) and imidazole (IM) on aluminum in 1.0 M HCl was investigated at 25 °C. Measurements were carried out under various experimental conditions using chemical (weight loss), and electrochemical (Tafel polarization and impedance) methods. Molecular dynamics (MD) method and density functional theory were also applied here for theoretical study. Results obtained showed that inhibition efficiency of these compounds increases with increase in their concentrations due to the formation of a surface film on the aluminum surface. Adsorption energy as well as hydrogen bond length calculations showed that AID was the best corrosion inhibitor among the tested imidazole derivatives. Polarization measurements reveal that the selected imidazole derivatives function mainly as cathodic-type inhibitors. Physisorption, followed by chemisorption was proposed as the mechanism for the inhibition process. Adsorption via H-bond formation was also considered here. Results obtained from theoretical study were found to confirm experimental findings.     

Microfluidic modeling and simulation of flow in membrane microreactors

We study the development of a mathematical model that describes isothermal microfluidic steady flow in a membrane microreactor, i.e., a silicon microreactor that houses a permeable membrane in one wall. The model employs the Navier-Stokes equation with appropriate boundary conditions for fluid permeation through the membrane and velocity slip at the walls to account for high Knudsen number. The model equations are solved analytically using finite Fourier transforms. The model solution is used to evaluate the effect of fluid permeation through the membrane and the Knudsen number on the velocity profile and pressure drop. For the simplified cases of no permeation and/or no slip, the derived solution is in excellent agreement with published experimental and theoretical results available in the literature. The utility of the model is illustrated by applying the results to a membrane microseparator used to separate hydrogen from the other effluents in a microreformer.     

Soft chemistry preparation of layered Al0.3V2O5·5H2O

A novel layered compound Al_0.3V₂O₅·5H₂O was successfully prepared and characterized using powder X-ray diffraction, Thermal analysis, scanning and transmission electron microscopes. The new layered Al_0.3V₂O₅·5H₂O has like-nanowires shape and the layered structure was stable until 400 °C. At higher temperature (500 °C), it decomposes to orthorhombic Al_xV₂O₅ and triclinic AlVO₄.