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Determination of Catechol by Cetyltrimethylammonium Bromide Functionalized Graphene Modified Electrode
Get PDFA simple and sensitive electrochemical sensor was prepared by using electrodeposition of the cetyltrimethylammonium Bromide (CTMAB ) functionalized Graphene (GR) on the glassy carbon electrode (GCE) to determine Catechol (CC) in water. The performance of the CTMAB functionalized GR sensor was studied and the analysis conditions of the CC were optimized. The experimental results showed that, compared with bare GCE, the redox peak current of CC on the modified electrode was obviously enhanced. Under the optimized conditions, the oxidation and reduction peak current all showed a good linear relationship with the concentration of CC from 5μmol/L to 1000 μmol/L. The detection limit of oxidation peak is 2.92 μmol/L, and that of reduction peak is 2.44 μmol/L. The recovery was founded to be in the range of 92.70 %~101.80 %. Moreover, the sensor could be used for the determination of CC in real samples with satisfactory results. And the mechanism of the sensitization of CC detected by CTMAB-GR modified GCE was discussed preliminarily
Innovative Material Technology: Chaotic Motion of Single-Walled Carbon Nanotube with Linear and Nonlinear Damping
Get PDFIn the present study, the effects on chaotic behaviors of single-walled carbon nanotube (SWCNT) due to the linear and nonlinear damping are investigated. By using the Hamilton's principle, the nonlinear governing equation of the single-walled carbon nanotube embedded in a matrix is derived. The Galerkin's method is adopted to simplify the integro-partial differential equation into a nonlinear dimensionless governing equation for the SWCNT, which turns out to be a forced Duffing equation. The variations of the Lyapunov exponents of the SWCNT with damping and harmonic forcing amplitudes are investigated. Based on the computations of the top Lyapunov exponent, it is concluded that the chaotic motion of the SWCNT occurs when the amplitude of the periodic excitation exceeds certain value, besides, the chaotic motion of the SWCNT occurs with small linear damping and tiny nonlinear damping
Studying of the Polylactide or Polyglycylidactide Surface Layer Biodegradation in Neutral Media for the Subsequent Layered Composite Creation
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The processes of biodegradation in phosphate buffer with pH 7.4 and 0.9 wt.% NaCl of polymer polylactide or polyglycylidactide films for the subsequent creation of a layered composite with a biodegradable layer on the basis of a nickel-free shape memory alloy TiNbTaZr were studied. The structure of the samples was determined by SEM and an optical microscope. For polylactide films the rate of biodegradation did not depend on the mass of the film. A gradual decrease in the rate of biodegradation at any mass with a similar dependence on time is noted. With an increase in the mass of films based on poly(glycolide-lactide) the rate of biodegradation increased. And even at the initial stage the dissolution rate is 2-3 times higher than in pure polylactide. On day 180, complete dissolution of the polyglycolidelactide was observed (even a precipitate was not observed) and completely entire polylactide films, however, lost their transparency, was noted
Model Reduction of Structured Dynamical Systems by Projecting onto the Dominant Eigenspace of the Gramians
Get PDFThis paper studies the structure preserving (second-order to second-order) model order reduction of second-order systems applying the projection onto the dominant eigenspace of the Gramians of the systems. The projectors which create the reduced order model are generated cheaply from the low-rank Gramian factors. The low-rank Gramian factors are computed efficiently by solving the corresponding Lyapunov equations of the system using the rational Krylov subspace method. The efficiency of the theoretical results are then illustrated by numerical experiments
New Implementation of Residual Power Series for Solving Fuzzy Fractional Riccati Equation
Get PDFThis paper reveals a computational method using a Residual Power Series Method (RPSM) for the solution of fuzzy fractional riccati equation under caputo fractional differentiability. An analytical solution of fuzzy fractional riccati equation is obtained as a convergent fractional power series. The procedure produces solutions of high accuracy, and some illustrative examples are solved with a different value of orders to show the efficiency of the RPSM
On Simplifications in the Technical Vision Algorithm
Get PDFThe purpose of the work is creation of a new technology for recognition of transport infrastructure facilities, including simplifications of algorithm for operation of technical facilities from video fixing under changing environmental factors. In this work, we used methods for determining the volume of three-dimensional facilities from the data of photo and video recording of the surrounding situation. The novelty of the research is building of decision algorithms based on devices and sensors that recognize changing road conditions, namely, defects in coverage. We obtained the algorithm of technical vision, which is supposed to implement as a program on a mobile device for recognition of transport infrastructure facilities and their defects by means of stereometry. One could use the data obtained in the planning of road repairs, in the analysis of traffic accidents by road police, for processing road users' complaints, etc
Synthesis and Characterization of Phase Change Material Microcapsules Using Different Emulsifiers
Get PDFIn this study, a series of phase change material microcapsules (MicroPCMs) were synthesized by a core-shell-like emulsion polymerization method using different emulsifiers. The interactions between core material, shell material and dispersed medium were investigated in detail. The copolymer (PS-MAA) of styrene and methylacrylic acid and paraffin were used as wall materials and core materials respectively. High temperature interfacial tensiometer was employed to measure the interactions between different materials. Fourier transformed infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetry (TG), Differential scanning calorimeter (DSC) and laser particle size analyzer were used to characterize the chemical structure, morphology, thermal properties, particles size and size distribution of the MicroPCMs. The results indicated that alkylphenol polyoxyethylene (OP-10) is the optimal emulsifier in this method. The MicroPCMs prepared by using OP-10 as emulsifier displayed smooth and compact surface, the productivity was as high as 93.35%. The melting enthalpy and crystallization enthalpy were -84.6J/g and 83.5J/g, respectively. The mean particle size was 16.33μm
Preparation and Free Radical Detection of Doped ZnO Nanomaterials
Get PDFNanomaterials play an important role in the field of optics and medicine, and rare earth cerium can act as a catalyst and a dopant to increase improve its optical properties. Used nanometer zinc oxide as a carrier, the Ag-ZnO and Ag-Ce-ZnO samples were prepared with the sol-gel method and characterized by X-ray diffractometer. The nanometer zinc oxide materials can generate the free hydroxyl radicals, so the methylene blue solution (MB) was used as the capture agent, and the free radicals produced by the doped nanometer zinc oxide were detected by UV-spectrophotometry. The results showed that the preparation particle size of the Ag-ZnO sample was about 75nm, particle size of the Ag-Ce-ZnO sample was about 70nm. The concentration of two samples treated with the dispersant PAAS generated hydroxyl radicals is much larger than the two samples treated with the dispersant SDBS. The doping of Ce ions not only improved the optical activity of the samples, but also increased the content of hydroxyl radicals. Rare-earth doped effe ctively improved the optical properties of the ZnO nanoparticles, and the effect of sample Ag-Ce-ZnO was better than Ag-ZnO samples. Discussion and study on the nature of both the nanometer zinc oxide and doped nanometer zinc oxide, as well as the method of preparation and the theory of produce hydroxyl radicals. In the experiment, doped nano-ZnO was used as carrier and methylene blue (MB) as capture reagent. This study provided a new method for the detection of free radicals drugs
Effect of Inhomogeneous Distribution of Alloying Elements on Integrity of Al-2.1 wt.% Mg Alloy Tubes and Welds
Get PDFAl-2.1 wt.% Mg alloy is an important nuclear research reactor material. The tubular products of the alloy are usually made by port-hole die extrusion process and several quality control steps are involved during fabrication to assess the quality of the weld joint. The paper describe two cases of failures of the alloy during fabrication. In one case, a thin wall tube failed during hydro-test at the weld-line while in another, a through-wall crack is observed at the heat affected zone (HAZ) of the weld joint between the thin tube and the tie-plate. In both the cases, the fracture surfaces have the appearance of brittle failure without any gross plastic deformation. Visual inspection, liquid penetrant testing, optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), Electron back scattered diffraction (EBSD) and micro-hardness measurement have been carried out for root cause analysis of the failures. EDS analysis at low KV indicates high Magnesium (Mg) and Silicon (Si) content at the fracture surface in both the cases. In the first case, segregation of these alloying elements at the weld-line in the port hole extruded tube has been observed. In the second case, the microstructure at the HAZ location shows grain boundary precipitation of low melting phase containing Mg, Si and Fe. Presence of Mg and Si reduce the solidus temperature of the grain boundary phase, which is responsible for HAZ liquation leading to failure under tensile stress during cooling
3D Modeling Method of Whole Structure for Turbo-generator Based on PROE-ANSOFT Information Interaction
Get PDFIn this paper, a new method based on PROE-ANSOFT Information Interaction for building 3D model of turbo-generator structure is proposed, which can solve those problems such as low efficiency of surface modeling, the lack of physical connection relation for the automatic turbo-generator integral structure, the occurrence of insufficient memory and even crashes for imported PROE model. Taking the stator winding coil of a turbo-generator as an example, the establishment process of 3D solid model is given. On this basis, the overall structure of turbo-generator in the ANSOFT working platform is completed. And the advantages and disadvantages of five kinds of simulation models in ANSOFT working platform are compared and analyzed. The results show that the 3D simulation model drawn by this method can be no longer limited to the special solution environment of electromagnetic field symmetry. Meanwhile, this model can simulate the real physical connection relationship, and complete the division of the simulation model, which will be helpful for the further simulation analysis of the finite element software