Mg(OH)2 Nanorods Synthesized by A Facile Hydrothermal Method in the Presence of CTAB

Nano-Micro Letters - Magnesium hydroxide (Mg(OH)2) nanorods were synthesized by a simple and facile hydrothermal method in the presence of cetyltetramethylammonium bromide (CTAB) as a surfactant....     

Effect of PEG-400 on the morphology and electrical properties of ZnO nanoparticles application for gas sensor

ZnO nanostructures were obtained by thermal decomposition of zinc hydroxide and PEG-400 formed after precipitation of zinc acetate from aqueous solution. The synthesized nanoparticles are characterized for their phase and morphology by X-ray diffraction (XRD) scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–visible spectrophotometry techniques. These characterizations are performed with the aim of optimizing the experimental conditions which allow us to obtain ZnO nanostructures. Electrical properties of the synthesized nanoparticles are studied by AC impedance measurement. The gas sensing properties are studied by reducing methane gas at room temperature.     

Multiscale Observation of the Fatigue‐Induced Damage Mechanisms in Carbon‐Black Filled Styrene‐Butadiene Rubber

Filled rubber materials exhibit a complex macroresponse characterized by stress softening, hysteresis, and dissipative heating when they are cyclically loaded. The relationship of these inelastic features to the microstructure changes is far from being fully established. This paper deals with the damage mechanisms in sulfur‐vulcanized styrene‐butadiene rubber (SBR) specimens in the diablo form reinforced with carbon‐black (CB) and zinc‐oxide (ZnO) fillers, and submitted to tension cyclic loading at room temperature. The microstructure alteration is characterized at different relevant scales and at different zones of the diabolo specimen by means of various technologies in the aim to report valuable insights about the mechanisms responsible for the macroresponse of this rubber‐filler material system. IR absorption spectra reveal that increasing filler content induces more interfacial interaction between CB and SBR chains. The environmental scanning electron microscopy (ESEM) observations show relevant altered morphologies of elastomeric chains with a predominant effect of both CB and ZnO fillers. A mesoscale observation of material density variation is presented using X‐ray computed tomography and the results are compared with those issued from ESEM.     

Synthesis and electrical properties of co-doping with La3+, Nd3+, Y3+, and Eu3+ citric acid-nitrate prepared samarium-doped ceria ceramics

Fluorite oxides Ce_0.8Sm_0.1Ln_0.1O_1.9 (denoted as SDC for singular doping and LnSDC for Ln=La, Nd, Y and Eu), were prepared by the citric acid–nitrate combustion reaction to act as electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFC). The thermal decomposition, phase identification, morphology, density, particle size distribution and electrical properties of the samples were studied by TGA/TDA, XRD, SEM, the Archimedes method, a laser size analyzer and Impedance spectroscopy, respectively. All crystallite powders that calcined at 800 °C had a cubic fluorite structure; the average crystallite size was between 63 and 68.5 nm. The pellets were then sintered at 1400 °C in air for 7 h. The relative densities of these pellets were over 95%, which was in good agreement with the results of the SEM. The impedance measurements were performed in an open circuit using two electrode configurations. The results showed that Ce_0.8Sm_0.1La_0.1O_1.9 had the highest electrical conductivity, σ_700 °C, equal to 6.59×10^?2 S cm^?1 and the lowest activation energy equal to 0.85 eV. It was therefore concluded that co-doping with the appropriate rare-earth cations can further improve the electrical properties of ceria electrolytes.     

State feedback tracking control for indirect field-oriented induction motor using fuzzy approach

This paper deals with the synthesis of fuzzy controller applied to the induction motor with a guaranteed model reference tracking performance. First, the Takagi-Sugeno (T-S) fuzzy model is used to approximate the nonlinear system in the synchronous d-q frame rotating with field-oriented control strategy. Then, a fuzzy state feedback controller is designed to reduce the tracking error by minimizing the disturbance level. The proposed controller is based on a T-S reference model in which the desired trajectory has been specified. The inaccessible rotor flux is estimated by a T-S fuzzy observer. The developed approach for the controller design is based on the synthesis of an augmented fuzzy model which regroups the model of induction machine, fuzzy observer, and reference model. The gains of the observer and controller are obtained by solving a set of linear matrix inequalities (LMIs). Finally, simulation and experimental results are given to show the performance of the observer-based tracking controller.     

Tumor microvasculature observed using different contrast agents: a comparison between Gd-DTPA-Albumin and B-22956/1 in an experimental model of mammary carcinoma

OBJECTIVE: The aim of this study was to compare a pure macromolecular contrast agent (Gd-DTPA-albumin) with a new protein-binding blood pool contrast agent (B22956/1) in terms of their capacity to investigate the microvasculature in an experimental model of mammary carcinoma. MATERIALS AND METHODS: Tumors were induced by subcutaneous injection of 5 x 10(5) BB1 cells into the backs of 5-7 week-old female FVB/neuNT233 mice. The animals were observed using DCE-MRI when the longest diameter of the tumor was 10.2+/-2.0 mm. DCE-MRI experiments were carried out using B22956/1 and (24 h later) Gd-DTPA-albumin. RESULTS: DCE-MRI data showed that vasculature in the tumor rim was characterized by greater fractional plasma volume and transendothelial permeability than vasculature in the tumor core as measured by both contrast agents. Permeability to Gd-DTPA-albumin in the tumor core was hardly measurable while permeability to B22956/1 was substantial. Histologically the tumor core showed areas of well vascularized, viable tissue surrounded by necrotic regions. CONCLUSIONS: DCE-MRI experiments performed with B22956/1 are useful in the investigation of vasculature in those tumor regions that are characterized by low permeability to macromolecules.     

Performance Optimization of Water-Cooled Concentrated Photovoltaic System

In this paper, a three-dimensional computational fluid dynamics model is developed to predict the thermal and electrical performance of a water-cooled concentrated photovoltaic (CPV) system. Based on the good agreement between the numerical results and experimental data from literature, an attempt was made to improve this system performance. Indeed, as the developed model is able to predict the thermal behavior of the different system components, many hot spots were detected in the cell module. In order to avoid this disadvantage while promoting solar cell cooling, the number of water cooling pipes of the CPV module was first increased and then a rectangular channel was employed. Numerical simulation results indicate the potential of the different modified systems for reducing these hot spots and the CPV module temperature, thus providing increased electrical and thermal efficiencies. The optimum design, which presents a solar cell temperature of 315.15 K and respectively a thermal and combined (thermal plus electrical) efficiency of 74.2% and 83.5%, is also evaluated.     

Improvement of bread quality and bread shelf-life by Bacillus subtilis biosurfactant addition

The objective of the present work was to determine the effect of the addition of a microorganism derived emulsifier on the quality of bread. The effect of Bacillus subtilis SPB1 biosurfactant has been investigated in comparison to a commercial surfactant, the soya lecithin. Indeed, it led to a better shape and a greater specific volume and voided fraction of loaves. Also, results showed that SPB1 bioemulsifier addition improved considerably the texture profile of bread, mainly at a concentration of 0.075%(w/w). In fact, we showed a notable decrease of firmness, chewiness, and adhesion values with a slight increase of cohesion for bread added emulsifier. According to crumb texture evolution during storage, SPB1 biosurfactant exhibited a significant antistaling effect. Moreover, SPB1 biosurfactant addition reduced significantly bread susceptibility to microbial contamination. These results proved that SPB1 biosurfactant could be of a great interest in the bread-making industry.     

Color Edge Detection Using Multidirectional Sobel Filter and Fuzzy Fusion

A new model is proposed in this paper on color edge detection that uses the second derivative operators and data fusion mechanism. The second-order neighborhood shows the connection between the current pixel and the surroundings of this pixel. This connection is for each RGB component color of the input image. Once the image edges are detected for the three primary colors: red, green, and blue, these colors are merged using the combination rule. Then, the final decision is applied to obtain the segmentation. This process allows different data sources to be combined, which is essential to improve the image information quality and have an optimal image segmentation. Finally, the segmentation results of the proposed model are validated. Moreover, the classification accuracy of the tested data is assessed, and a comparison with other current models is conducted. The comparison results show that the proposed model outperforms the existing models in image segmentation.